CA1319958C - Portable radio apparatus having battery saved channel scanning function - Google Patents
Portable radio apparatus having battery saved channel scanning functionInfo
- Publication number
- CA1319958C CA1319958C CA000559465A CA559465A CA1319958C CA 1319958 C CA1319958 C CA 1319958C CA 000559465 A CA000559465 A CA 000559465A CA 559465 A CA559465 A CA 559465A CA 1319958 C CA1319958 C CA 1319958C
- Authority
- CA
- Canada
- Prior art keywords
- channels
- channel
- scanning
- signal
- data
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W48/00—Access restriction; Network selection; Access point selection
- H04W48/16—Discovering, processing access restriction or access information
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/02—Power saving arrangements
- H04W52/0209—Power saving arrangements in terminal devices
- H04W52/0225—Power saving arrangements in terminal devices using monitoring of external events, e.g. the presence of a signal
- H04W52/0245—Power saving arrangements in terminal devices using monitoring of external events, e.g. the presence of a signal according to signal strength
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
Abstract of the Disclosure A portable radio apparatus comprises a receiving section capable of being tuned to any of a plurality of channels, a switch circuit for controlling supply of power from ? battery to the receiving section and a detector circuit for detecting strength of electric fields which are developed on said channels. A control section is connected to said receiving section and the switch circuit and constructed such that, in response to an output of said detector circuit, the control section executes channel scanning for tuning the receiving section sequentially to the channels while, at this instant, controlling said switch circuit to feed power continuously to the receiving section and, when no data has appeared on said channels within a first predetermined period of time during the channel scanning, executes saving scanning for repeating a cycle in which said channels are sequentially scanned by one round and, then, the scanning is interrupted for a second predetermined period of time while, at this instant, controlling the switch circuit to feed power to the receiving section in synchronism with the saving scanning.
Description
1319~38 The present invention relates to a portable radio apparatus for a vehicle telephone system or the like, and, more particularly, to a portable radio apparatus having a channel scanning function.
In a vehicle telephone system, for example, there are provided control channels and audio channels, and a mobile subscriber receiver is tuned to any of the control channels in a waiting condition. While an electric field is not developed on the control channel to which the receiver is tuned, the receiver performs channel scanning repeatedly until it finds a control channel with an electric field. A receiver with an implementation for saving power while data reception is under way with an electric field developed is disclosed in Japanese Laid-Open Patent Publication (Kokai) No.
15 98030/1986, or Patent Application No. 219231/1979, which is assigned to the applicant of the instant application and laid open May 16, lg86.
Specifically, the above-mentioned receiver is constructed such that a serially received data stream is converted into parallel data by a serial-to-parallel converter and, only when parallel outputs of the converter are received, a microprocessor is operated intermittently. Such intermittent operation of the microprocessor is successful in reducing power which is consumed by the entire receiver. This prior art receiver, however, suffers from a drawback that battery saving is not guaranteed while received data is absent under a no-field condition, although it is achievable during data reception. More specifically, in a no-field condition, the receiver performs channels scanning continuously in order to acquire a channel on which an electric field is developed, causing a receiving section thereof to consume power without cease.
It is, therefore, an object of the present invention to provide a portable radio apparatus which successfully implements a battery saving function during channel scanning.
_, , ,, 2 1319~8 It is another object of the present invention to provide a portable radio apparatus with a battery saving function which hardly causes data reception to fail while channel scanning is under way.
It is a further object of the present invention to provide a portable radio apparatus which allows a call to be originated at any desired time even during battery saved channel scanning.
Accordingly, one aspect of the invention provides a portable radio apparatus comprising: a receiving section capable of being tuned to any of a plurality of channels; a switch circuit for controlling supply of power from a battery to said receiving section: a detector circuit for detecting strength of electric fields which are developed on said channels; and a control section connected to said receiving section and said switch circuit and constructed such that, in response to an output of said detector circuit, said control section executes channel scanning for tuning said receiving section sequentially to said channels while, at this instant, controlling said switch circuit to feed power continuously to said receiving section and, when no data has appeared on said channels within a first predetermined period of time during said channel scanning, executes saving scanning for repeating a cycle in which said channels are sequentially scanned by one round and, then the scanning is interrupted for a second predetermined period of time while, at this instant, controlling said switch circuit to feed power to said receiving section in synchronism with said saving scanning.
Another aspect of the invention provides a portable radio apparatus having an intermittent scanning function, comprising: a radio section capable of being tuned to any of a plurality of channels; a power switch for establishing and interrupting supply of power to said radio section; means for, in a waiting condition, controlling said radio section to sequentially scan control channels while measuring reception levels on said respective control channels, tuning ~,-3 13lg9~8 sai.d radio section to one of said control channels which has the! highest reception level and, if necessary, to another of said control channels which has the second highest reception level, repeating said channel scanning when no data is received, and interrupting supply of power to corresponding portions except for said radio section and a timer section by controlling said power switch when data is not received for a predetermined period of time; means for resuming said channel scanning ~)y feeding power to said portions, which have been disconnected from said radio section, at predetermined time intervals after the interruption of the power supply: and means for interrupting said saving scanning and executing said channel scanning instead, when a predetermined condition is reached.
A further aspect of the invention provides a portable radio apparatus comprising: receiving means capable of being tuned to any of a plurality of channels in response to any of a plurality of channels designating signals which are individually associated with said channels; power switch means responsive to a control signal for feeding power to said receiving means; decision means for deciding whether or not data is present on any of said channels to which said receiving means is tuned; first means for, when an output of said decision means is indicative of absence of data on said channels, feeding said channel designating signals to said receiving means while switching said channel designating signals cyclically and sequentially; second means for, when said first means has operated continuously for more than a predetermined period of time, feeding said channel designating signals to said receiving means cyclically and intermittently;
and third means for feeding said control signal to said power switch means in synchronism with operation timings of said first and second means.
A still further aspect of the invention provides a method of scanning channels of a portable radio apparatus, comprising the steps of: tuning a receiving section to any .~
In a vehicle telephone system, for example, there are provided control channels and audio channels, and a mobile subscriber receiver is tuned to any of the control channels in a waiting condition. While an electric field is not developed on the control channel to which the receiver is tuned, the receiver performs channel scanning repeatedly until it finds a control channel with an electric field. A receiver with an implementation for saving power while data reception is under way with an electric field developed is disclosed in Japanese Laid-Open Patent Publication (Kokai) No.
15 98030/1986, or Patent Application No. 219231/1979, which is assigned to the applicant of the instant application and laid open May 16, lg86.
Specifically, the above-mentioned receiver is constructed such that a serially received data stream is converted into parallel data by a serial-to-parallel converter and, only when parallel outputs of the converter are received, a microprocessor is operated intermittently. Such intermittent operation of the microprocessor is successful in reducing power which is consumed by the entire receiver. This prior art receiver, however, suffers from a drawback that battery saving is not guaranteed while received data is absent under a no-field condition, although it is achievable during data reception. More specifically, in a no-field condition, the receiver performs channels scanning continuously in order to acquire a channel on which an electric field is developed, causing a receiving section thereof to consume power without cease.
It is, therefore, an object of the present invention to provide a portable radio apparatus which successfully implements a battery saving function during channel scanning.
_, , ,, 2 1319~8 It is another object of the present invention to provide a portable radio apparatus with a battery saving function which hardly causes data reception to fail while channel scanning is under way.
It is a further object of the present invention to provide a portable radio apparatus which allows a call to be originated at any desired time even during battery saved channel scanning.
Accordingly, one aspect of the invention provides a portable radio apparatus comprising: a receiving section capable of being tuned to any of a plurality of channels; a switch circuit for controlling supply of power from a battery to said receiving section: a detector circuit for detecting strength of electric fields which are developed on said channels; and a control section connected to said receiving section and said switch circuit and constructed such that, in response to an output of said detector circuit, said control section executes channel scanning for tuning said receiving section sequentially to said channels while, at this instant, controlling said switch circuit to feed power continuously to said receiving section and, when no data has appeared on said channels within a first predetermined period of time during said channel scanning, executes saving scanning for repeating a cycle in which said channels are sequentially scanned by one round and, then the scanning is interrupted for a second predetermined period of time while, at this instant, controlling said switch circuit to feed power to said receiving section in synchronism with said saving scanning.
Another aspect of the invention provides a portable radio apparatus having an intermittent scanning function, comprising: a radio section capable of being tuned to any of a plurality of channels; a power switch for establishing and interrupting supply of power to said radio section; means for, in a waiting condition, controlling said radio section to sequentially scan control channels while measuring reception levels on said respective control channels, tuning ~,-3 13lg9~8 sai.d radio section to one of said control channels which has the! highest reception level and, if necessary, to another of said control channels which has the second highest reception level, repeating said channel scanning when no data is received, and interrupting supply of power to corresponding portions except for said radio section and a timer section by controlling said power switch when data is not received for a predetermined period of time; means for resuming said channel scanning ~)y feeding power to said portions, which have been disconnected from said radio section, at predetermined time intervals after the interruption of the power supply: and means for interrupting said saving scanning and executing said channel scanning instead, when a predetermined condition is reached.
A further aspect of the invention provides a portable radio apparatus comprising: receiving means capable of being tuned to any of a plurality of channels in response to any of a plurality of channels designating signals which are individually associated with said channels; power switch means responsive to a control signal for feeding power to said receiving means; decision means for deciding whether or not data is present on any of said channels to which said receiving means is tuned; first means for, when an output of said decision means is indicative of absence of data on said channels, feeding said channel designating signals to said receiving means while switching said channel designating signals cyclically and sequentially; second means for, when said first means has operated continuously for more than a predetermined period of time, feeding said channel designating signals to said receiving means cyclically and intermittently;
and third means for feeding said control signal to said power switch means in synchronism with operation timings of said first and second means.
A still further aspect of the invention provides a method of scanning channels of a portable radio apparatus, comprising the steps of: tuning a receiving section to any .~
4 1319~8 of a plurality of channels; feeding power to said receiving section in response to a control signal; deciding whether or not data is present on said channel to which said receiving section is tuned; when data is not present on said channels, tuning said receiving section to said respective channels cyclically and continuously: when said cyclic and continuous tuning operation has continued for more than a predetermined period of time, tuning said receiving section to said respective channels cyclically and intermittently; and feeding power to said receiving section continuously during said continuous tuning operation and intermittently during said intermittent tuning operation.
Thus, the portable radio apparatus of the present invention includes a receiving section which is selectively tuned to a plurality of channels, a switch circuit for controlling the supply of power to the receiving section, a detecting circuit responsive to the strength of electric fields which may be developed on the respective channels, and a control section for controlling channel scanning performed by the -eceiving section as well as opening and closing of the switch circuit. As indicated, the control section so controls the switch circuit as to feed power to the receiving section continuously during channel scanning. When channel scanning has continued for more than a predetermined period of time, the control section starts on saving scanning in which the channel scanning occurs intermittently. During such saving scanning, power is fed to the receiving section timed to the saving scanning. The saving scanning successfully implements battery saving in the event of channel scanning.
Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a schematic block diagram showing a portable radio apparatus embodying the present invention;
Figure 2 is a flowchart demonstrating a channel scanning routine as performed by the apparatus of Figure l;
, ,......
1319 ~ ~ ~
4a Figure 3 is a chart schematically showing a channel arrangement which the apparatus of Figure l uses;
Figures 4A and 4B are timing charts showing a transition from usual channel scanning to battery saved channel scanning (hereinafter referred to as saving scanning for simplicity) which occurs in the apparatus of Figure l;
Figures 5A and 5B are timing charts representative of a condition in which the apparatus of Figure l is performing the saving scanning;
Figures 6A and 6B are timing charts showing a condition in which data is received while the apparatus of Figure 1 is performing the saving scanning;
Figures 7A and. 7B are timing charts showing a condition in which data is keyed in while the apparatus of Figure 1 is effecting the saving scanning;
Figure 8 is a schematic block diagram showing a specific construction of a receive frequency synthesizer which is included in the apparatus of Figure 1;
Figure 9 is a diagram showing a power switch circuit also included in the apparatus of Figure 1; and Figure lO is a schematic block diagram of a receiver which is shown in Figure l and includes a field strength detector.
Referring to Figure l, a portable vehicle-mounted telephone to which the present invention is applied is . .
~3~ 8 shown and generally designated by reference numeral 100.
The telepnone 100 is representative of one'subscriber telephone which is included in a vehi-le telephone system and connected to an ordinary public telephone network via a central station, not shown. Specifically, the telephone 100 is capable of communicating with ordinary subscriber telephones and other vehicle-mounted telephones by way of the central station and public telephone network.
A signal picked up by an antenna 1, e.g., a frequency modulated (FM) signal is fed via an antenna duplexer 2 to a receiver 31 which is included in a receiving (RX) section 3. Demodulating the received FM signal, the receiver 31 delivers an audio signal to a speaker 6 and a control signal and other data to a central processing unit (CPU) 5. On the other hand, an audio signal entered through a microphone 7 and data from the CPU 5 are applied to a transmitter 41 which is built in a transmitting (TX) section 4. The transmitter 41 subjects the incoming signal to, for example, frequency modulation and, then, applies the resulting signal to the antenna 1 via the antenna duplexer 2. This signal is sent from the antenna 1 to the central station.
The CPU 5 controls the entire telephone 100. To tune the receiver 31 and transmitter 41 to a given channel, the CPU 5 delivers a channel designating signal to a receive and a transmit frequency synthesizer 32 and 42, respectively.
- 6 - 13`~9~g In response, the synthesizers 32 and 42 apply to, respectively, the receiver 31 and transmit~er 41 signals each having an oscillation frequency which is associated with the channel designating signal. The CPU 5 receives a call originating signal, a dial signal and others from a keyboard 8 as well. Further, the CPU 5 controls a RX
power switch circuit 9 for controlling the supply of power from a battery 11 to the RX section 3, and it also controls a TX power switch circuit 10 for controlling the supply of power from the battery 11 to the TX section 4. The CPU 5 is constantly powered so long as a power switch 12 is closed.
The TX power switch circuit 10 is so controlled as to interrupt the power supply in a waiting condition and to establish it during the transmission of control data and during communication. In the case of a voice-operated transmitter (VOX), the circuit 10 may be controlled such that power is fed only when an audio signal is present during communication. The RX power switch circuit 9 is controlled to perform a battery saving operation during channel scanning, and the present invention is deeply concerned with this control. More specifically, when a predetermined period of time such as 60 seconds expires bèfore any data appears on any of the control channels during channel scanning, a battery saving mode is initiated in which power is intermittently supplied to _ 7 _ 13199~8 the transmitter 31. In the battery saving mode, power is supplied for a period of time which allows' all the control channels to be scanned by one cycle and, then, it is interrupted upon the lapse of a predetermined period of time such as 9 seconds. This manner of channel scanning is referred to as saving scanning in this specification.
As soon as any data is detected on any of the con~trol channels during saving scanning, power is continuously applied to the RX section 3 to allow the latter to receive the following data. On the other hand, when data is keyed in on the keyboard 8, the supply of power of the RX section 3 begins at that instant.
Referring to Fig. 2, a channel scanning routine of the apparatus is shown. Upon the start of channel scanning (step S0), whether the system status is A or B is dete~mined in step Sl. The system status will be briefly described with reference to Fig. 3. This system has 1,000 channels in total, i.e., audio channels (V-CH) #1 to #22, #44 to #322 and #344 to #1,000 and control channels (C-CH) #23 to #43 and #323 to #343. In each receiver included in the system, a status A or a status B is written as a system status in a read only memory which stores an identification (ID) nulTIber assigned to the own station (ID-ROM). If it i`s the status A that is written in the ID-ROM, the receiver scans the control channels #23 to #43 first and, then, the control channels #323 to #343. If the status B is written - 8 - ~ 8 in the ID-ROM, the receiver scans the control channels #323 to #343 and, then, the control channels #23 to #43.
This is to prevent particular control channels from being overloaded.
In Fig. 2, if the status is A as decided in step Sl, the control channels #23 to #43 are scanned as stated above so as to store the numbers assigned to those channels which have the strongest and the second strongest field strength, respectively (steps S2A and S3A). Then, in step S4A, whether or not data is present on the channel having the strongest field strength is determined and, if it is present, the program advances to step S7 for taking in that data. If data is not present on that channel, step S5A is executed to see if data is present on the channel having the second strongest field strength. If data is present on that channel, the program advances to step S7 to take it in while, if it is absent, the operation is transferred to step S2B by way of step S6A.
If the status is B as determined in step Sl, the control channels #323 to #343 are sequentially scanned at step S2B so that those channels having the strongest and second strongest field strength are stored in step S3B.
These steps S3B to S5B are exactly the same in operation as the previously mentioned steps S3A to S5A. If no data is found on the channel having the second strongest field strength as decided in step S5B, the program returns to step S2A through step S6B.
131~8 Each of the steps S6A and S6B is adapted to see if all the forty two control channels have been scanned.
If they have not been fully scanned, steps S6A and S6B
are followed by, respectively, steps S2B and S2A to scan all of them. As all the forty two control channels are scanned, the channel scanning routine is once terminated.
However, even after the termination of the channel scanning routine, the program returns to the start (step S0) while channel scanning is executed in the ordinary mode which is distinguished from the saving scan mode, as described in detail later.
A reference will be made to Figs. 4A, 4B, 5A, 5B, 6A, 6B, 7A and 7B for explaining the saving scanning which is the characteristic operation in accordance with the present invention. When the apparatus is powered at a time tO or a ce~tain control channel is turned from a data present state to a data absent, or no-data state at the time tO, the channel scanning operation previously stated with reference to Fig. 2 is initiated. Since the system status of the radio apparatus is assumed to be A, the apparatus scans the control channels #23 to #43 from the time tO to a time tl and, then, the control channels #323 to #343 from the time tl to a time t2. This scanning procedure is repeated thereafter. The period of time necessary for scanning one channel is about 40 milliseconds and, there-fore, about 1.7 seconds are needed to scan the forty two - lo - ~13~9~8 control channels by one round. When any data is not found on any of the channels upon the lapse of a,predetermined period of time, e.g., 60 seconds after the channel scanning has been started at the time tO, the saving scanning is S initiated. The supply of power to the RX section 3, Fig. 1, is interrupted at a time t5 and onward.
What occurs during the saving scanning is shown in Figs. 5A and 5B. As shown, at a time t6, power supply to the RX section 3 begins while, at the same time, channel scanning begins. When any data is not found on any of the control channels #23 to #43 and #323 to #343 by one checking cycle, the power supply is interrupted at a time t7 so as to start a saving mode. In the saving mode, the power supply and the channel scanning are each stopped for a predetermined period of time such as 9 seconds. Then, at a time t8, the saving mode is replaced with the channel scanning mode again. During the interval between times t8 and t9, the same operation as that performed during the interval between the times t6 and t7 is performed.
Figs. 6A and 6B are representative of an exemplary condition wherein data is found on the control channel #30 during the saving scanning. In Fig. 6B, the saving scanning operation shown in Figs. 5A to 5B is performed from a time tlO to a time tl2. When data is detected on the control ~5 channel #30 while the control channels #23 to #43 are sequentially scanned during the interval between times tl2 3 ~ 8 and tl3, the saving scanning is interrupted at the time tl3 while, at the same time, the channel is fixed to #30 so as to start taking in the data.
Figs. 7~ and 7B show another exemplar~ condition in which data is keyed in while the saving scanning is under way. During the interval between times tl4 and tl5, channel scanning is performed. Assuming that a key input occurs at a time tl6 while the power supply is interrupted, the saving scanning is immediately stopped and replaced with an ordinary continuous scanning mode. It is to be noted that the words "key input" mentioned above applies to any of the keys which are provided on the keyboard 8, Fig. 1, and may be operated as desired. This is because, whatever the key operated may be, it is decided that the subscriber has intended to take some action such as origination of a call. Further, a key input is validated at any time during the saving scanning so that usual channel scanning is resumed.
Referring to Fig. 8, a specific construction of the receive frequency synthesizer 32 is shown and includes a reference oscillator 81. The reference oscillator 81 generates a reference oscillation signal while a reference divider 82 divides the reference oscillation signal by a predetermined number. The output of the reference divider 82 is fed to one input terminal of a phase comparator 83 to the other input terminal of which an output of a - 12 - 13199a8 programmable counter 89 is applied. Comparing the two input signals with respect to phase, the phase comparator 83 produces a phase error signal and delivers it to a charge pump 84. In response, the charge pump 84 drives a loop filter 85 by supplying it with a current which is associated with the phase error signal. The low-pass output of the filter 85 is fed to a voltage controlled oscillator (VC0) 86 as an oscillation control signal.
The output of VC0 86 is coupled, through a buffer amplifier 87, to a variable prescaler 88 which is adapted for predetermined division. The output of the prescaler 88 is further divided by the programmable counter 89 and, then, routed to the phase comparator 83. The division ratio of the prescaler 88 has two different stages which are selectively set up by a control counter 90.
A channel designating signal is fed from the CPU 5, Fig. 1, to a serial-to-parallel converter 91 to be thereby converted into parallel signals, the parallel signals being applied to the counters 89 and 90. Each of the counters 89 and 90, therefore, is loaded with a particular division ratio which is associated with the channel designating signal. Since the elements 81 to 91 constitute in combination a programmable phase locked loop (PLL), a signal whose frequency is associated with the channel designating signal which is applied the serial-to-parallel converter 91 appears on the output of VC0 86. The output -- 13 - ~31~9~8 of VCO 86 is also applied to a frequency multiplier 91.
The output of multiplier 92 is routed to the receiver 31, Fig. 1, through a buffer amplifier 93 and a band-pass filter 94.
The supply of power to the reference oscillator 81, charge pump 84, VCO 86, buffer amplifier 87, prescaler 88, multiplier 92 and buffer amplifier 93 is controlled by the ~X power switch circuit 9, Fig. 1. It is to be noted that a block demarcated by a dashed line in Fig. 8 and designated by the reference numeral 95 is implemented with a one-chip complementary metal oxide semiconductor (CMOS~.
Referring to Fig. 9, a specific construction of the RX power switch circuit 9 is shown. As shown, a PNP
transistor 91 has an emitter E and a collector C which are connected to the power switch 12 and the RX section 3, respectively. The base B of transistor 91 is connected to the CPU 5 via a resistor 93 and to the emitter E via a resistor 92. When the CPU 5 delivers a low level signal, the transistor 91 is rendered conductive resulting that power is fed to the RX section 3. Conversely, when the CPU 5 delivers a high level signal, the transistor 91 is turned off to interrupt the supply of power to the RX
section 3.
` Fig. 10 is a block diagram showing the receiver 31 which includes a field strength detector 60. The receiver is of a double superheterodyne type which per se is well i3~9~8 known in the art and, therefore, it will be briefly ~escribed hereinafter. A received signal coming in through the antenna duplexer 2 is applied to a first mixer 51 to be mixed down into a first intermediate frequency (IF) signal.
A local oscillation signal is fed to the mixer 51 from the receive frequency synthesizer 32, Fig. 1. The first IF
signal is propagated through a first IF ~and-pass filter 52 to a second mixer 53 which then mixes the input IF signal with a local oscillation signal fed from a local oscillator 54 so as to mix it down into a second IF signal. This second IF signal is passed through a second IF band-pass filter 55, then amplified by an IF amplifier 56, and then limited in amplitude by a limiter 57.
The output of limiter 57 is routed to a frequency discriminator 58 on one hand and to the field strength detector 60 on the other hand. The frequency discriminator 58 demodulates the second IF signal to produce an audio frequency (AF) signal which is applied to an AF circuit 59.
The AF circuit 59 includes an AF amplifier, a low pass filter (LPF) and others and delivers its output to the speaker 6 and CPU 5.
The field strength detector 60 includes an envelope detector 61 which is adapted to detect the envelope of the outputs of the limiter 51 by detecting those outputs. An analog-to-digital (A/D) converter 62 converts the levels of the envelope detected and feeds the resulting digital signal to the CPU 5.
- 15 - 131~
The supply of power to the first and second mixers 51 and 53, local oscillator 59, IF amplifier 56, limiter 57, frequency discriminator 58, AF circuit 59 and field strength detector 60 is controlled by the RX power swltch circuit 9.
In summary, it will be seen that the present invention realizes a vehicle-mounted telephone which is usable over a long time with a minimum of current consumption. This is because channel scanning is effected intermittently to search for a channel with an electric field even when the telephone is left in poor electric field environments, the power consumption thus being suppressed. Another advantage attainable with the present invention is that, since the intermittent channel scanning operation is interrupted for a predetermined period of time after the reception of data, there occurs no delay in response due to the intermittent operation even in those environments which suffer from sharp changes in electric field.
Further, the delay in response to an operator due to the intermittent operation is eliminated because, after any data has been keyed in, the intermittent operation is not performed until a predetermined period of time expires.
Thus, the portable radio apparatus of the present invention includes a receiving section which is selectively tuned to a plurality of channels, a switch circuit for controlling the supply of power to the receiving section, a detecting circuit responsive to the strength of electric fields which may be developed on the respective channels, and a control section for controlling channel scanning performed by the -eceiving section as well as opening and closing of the switch circuit. As indicated, the control section so controls the switch circuit as to feed power to the receiving section continuously during channel scanning. When channel scanning has continued for more than a predetermined period of time, the control section starts on saving scanning in which the channel scanning occurs intermittently. During such saving scanning, power is fed to the receiving section timed to the saving scanning. The saving scanning successfully implements battery saving in the event of channel scanning.
Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a schematic block diagram showing a portable radio apparatus embodying the present invention;
Figure 2 is a flowchart demonstrating a channel scanning routine as performed by the apparatus of Figure l;
, ,......
1319 ~ ~ ~
4a Figure 3 is a chart schematically showing a channel arrangement which the apparatus of Figure l uses;
Figures 4A and 4B are timing charts showing a transition from usual channel scanning to battery saved channel scanning (hereinafter referred to as saving scanning for simplicity) which occurs in the apparatus of Figure l;
Figures 5A and 5B are timing charts representative of a condition in which the apparatus of Figure l is performing the saving scanning;
Figures 6A and 6B are timing charts showing a condition in which data is received while the apparatus of Figure 1 is performing the saving scanning;
Figures 7A and. 7B are timing charts showing a condition in which data is keyed in while the apparatus of Figure 1 is effecting the saving scanning;
Figure 8 is a schematic block diagram showing a specific construction of a receive frequency synthesizer which is included in the apparatus of Figure 1;
Figure 9 is a diagram showing a power switch circuit also included in the apparatus of Figure 1; and Figure lO is a schematic block diagram of a receiver which is shown in Figure l and includes a field strength detector.
Referring to Figure l, a portable vehicle-mounted telephone to which the present invention is applied is . .
~3~ 8 shown and generally designated by reference numeral 100.
The telepnone 100 is representative of one'subscriber telephone which is included in a vehi-le telephone system and connected to an ordinary public telephone network via a central station, not shown. Specifically, the telephone 100 is capable of communicating with ordinary subscriber telephones and other vehicle-mounted telephones by way of the central station and public telephone network.
A signal picked up by an antenna 1, e.g., a frequency modulated (FM) signal is fed via an antenna duplexer 2 to a receiver 31 which is included in a receiving (RX) section 3. Demodulating the received FM signal, the receiver 31 delivers an audio signal to a speaker 6 and a control signal and other data to a central processing unit (CPU) 5. On the other hand, an audio signal entered through a microphone 7 and data from the CPU 5 are applied to a transmitter 41 which is built in a transmitting (TX) section 4. The transmitter 41 subjects the incoming signal to, for example, frequency modulation and, then, applies the resulting signal to the antenna 1 via the antenna duplexer 2. This signal is sent from the antenna 1 to the central station.
The CPU 5 controls the entire telephone 100. To tune the receiver 31 and transmitter 41 to a given channel, the CPU 5 delivers a channel designating signal to a receive and a transmit frequency synthesizer 32 and 42, respectively.
- 6 - 13`~9~g In response, the synthesizers 32 and 42 apply to, respectively, the receiver 31 and transmit~er 41 signals each having an oscillation frequency which is associated with the channel designating signal. The CPU 5 receives a call originating signal, a dial signal and others from a keyboard 8 as well. Further, the CPU 5 controls a RX
power switch circuit 9 for controlling the supply of power from a battery 11 to the RX section 3, and it also controls a TX power switch circuit 10 for controlling the supply of power from the battery 11 to the TX section 4. The CPU 5 is constantly powered so long as a power switch 12 is closed.
The TX power switch circuit 10 is so controlled as to interrupt the power supply in a waiting condition and to establish it during the transmission of control data and during communication. In the case of a voice-operated transmitter (VOX), the circuit 10 may be controlled such that power is fed only when an audio signal is present during communication. The RX power switch circuit 9 is controlled to perform a battery saving operation during channel scanning, and the present invention is deeply concerned with this control. More specifically, when a predetermined period of time such as 60 seconds expires bèfore any data appears on any of the control channels during channel scanning, a battery saving mode is initiated in which power is intermittently supplied to _ 7 _ 13199~8 the transmitter 31. In the battery saving mode, power is supplied for a period of time which allows' all the control channels to be scanned by one cycle and, then, it is interrupted upon the lapse of a predetermined period of time such as 9 seconds. This manner of channel scanning is referred to as saving scanning in this specification.
As soon as any data is detected on any of the con~trol channels during saving scanning, power is continuously applied to the RX section 3 to allow the latter to receive the following data. On the other hand, when data is keyed in on the keyboard 8, the supply of power of the RX section 3 begins at that instant.
Referring to Fig. 2, a channel scanning routine of the apparatus is shown. Upon the start of channel scanning (step S0), whether the system status is A or B is dete~mined in step Sl. The system status will be briefly described with reference to Fig. 3. This system has 1,000 channels in total, i.e., audio channels (V-CH) #1 to #22, #44 to #322 and #344 to #1,000 and control channels (C-CH) #23 to #43 and #323 to #343. In each receiver included in the system, a status A or a status B is written as a system status in a read only memory which stores an identification (ID) nulTIber assigned to the own station (ID-ROM). If it i`s the status A that is written in the ID-ROM, the receiver scans the control channels #23 to #43 first and, then, the control channels #323 to #343. If the status B is written - 8 - ~ 8 in the ID-ROM, the receiver scans the control channels #323 to #343 and, then, the control channels #23 to #43.
This is to prevent particular control channels from being overloaded.
In Fig. 2, if the status is A as decided in step Sl, the control channels #23 to #43 are scanned as stated above so as to store the numbers assigned to those channels which have the strongest and the second strongest field strength, respectively (steps S2A and S3A). Then, in step S4A, whether or not data is present on the channel having the strongest field strength is determined and, if it is present, the program advances to step S7 for taking in that data. If data is not present on that channel, step S5A is executed to see if data is present on the channel having the second strongest field strength. If data is present on that channel, the program advances to step S7 to take it in while, if it is absent, the operation is transferred to step S2B by way of step S6A.
If the status is B as determined in step Sl, the control channels #323 to #343 are sequentially scanned at step S2B so that those channels having the strongest and second strongest field strength are stored in step S3B.
These steps S3B to S5B are exactly the same in operation as the previously mentioned steps S3A to S5A. If no data is found on the channel having the second strongest field strength as decided in step S5B, the program returns to step S2A through step S6B.
131~8 Each of the steps S6A and S6B is adapted to see if all the forty two control channels have been scanned.
If they have not been fully scanned, steps S6A and S6B
are followed by, respectively, steps S2B and S2A to scan all of them. As all the forty two control channels are scanned, the channel scanning routine is once terminated.
However, even after the termination of the channel scanning routine, the program returns to the start (step S0) while channel scanning is executed in the ordinary mode which is distinguished from the saving scan mode, as described in detail later.
A reference will be made to Figs. 4A, 4B, 5A, 5B, 6A, 6B, 7A and 7B for explaining the saving scanning which is the characteristic operation in accordance with the present invention. When the apparatus is powered at a time tO or a ce~tain control channel is turned from a data present state to a data absent, or no-data state at the time tO, the channel scanning operation previously stated with reference to Fig. 2 is initiated. Since the system status of the radio apparatus is assumed to be A, the apparatus scans the control channels #23 to #43 from the time tO to a time tl and, then, the control channels #323 to #343 from the time tl to a time t2. This scanning procedure is repeated thereafter. The period of time necessary for scanning one channel is about 40 milliseconds and, there-fore, about 1.7 seconds are needed to scan the forty two - lo - ~13~9~8 control channels by one round. When any data is not found on any of the channels upon the lapse of a,predetermined period of time, e.g., 60 seconds after the channel scanning has been started at the time tO, the saving scanning is S initiated. The supply of power to the RX section 3, Fig. 1, is interrupted at a time t5 and onward.
What occurs during the saving scanning is shown in Figs. 5A and 5B. As shown, at a time t6, power supply to the RX section 3 begins while, at the same time, channel scanning begins. When any data is not found on any of the control channels #23 to #43 and #323 to #343 by one checking cycle, the power supply is interrupted at a time t7 so as to start a saving mode. In the saving mode, the power supply and the channel scanning are each stopped for a predetermined period of time such as 9 seconds. Then, at a time t8, the saving mode is replaced with the channel scanning mode again. During the interval between times t8 and t9, the same operation as that performed during the interval between the times t6 and t7 is performed.
Figs. 6A and 6B are representative of an exemplary condition wherein data is found on the control channel #30 during the saving scanning. In Fig. 6B, the saving scanning operation shown in Figs. 5A to 5B is performed from a time tlO to a time tl2. When data is detected on the control ~5 channel #30 while the control channels #23 to #43 are sequentially scanned during the interval between times tl2 3 ~ 8 and tl3, the saving scanning is interrupted at the time tl3 while, at the same time, the channel is fixed to #30 so as to start taking in the data.
Figs. 7~ and 7B show another exemplar~ condition in which data is keyed in while the saving scanning is under way. During the interval between times tl4 and tl5, channel scanning is performed. Assuming that a key input occurs at a time tl6 while the power supply is interrupted, the saving scanning is immediately stopped and replaced with an ordinary continuous scanning mode. It is to be noted that the words "key input" mentioned above applies to any of the keys which are provided on the keyboard 8, Fig. 1, and may be operated as desired. This is because, whatever the key operated may be, it is decided that the subscriber has intended to take some action such as origination of a call. Further, a key input is validated at any time during the saving scanning so that usual channel scanning is resumed.
Referring to Fig. 8, a specific construction of the receive frequency synthesizer 32 is shown and includes a reference oscillator 81. The reference oscillator 81 generates a reference oscillation signal while a reference divider 82 divides the reference oscillation signal by a predetermined number. The output of the reference divider 82 is fed to one input terminal of a phase comparator 83 to the other input terminal of which an output of a - 12 - 13199a8 programmable counter 89 is applied. Comparing the two input signals with respect to phase, the phase comparator 83 produces a phase error signal and delivers it to a charge pump 84. In response, the charge pump 84 drives a loop filter 85 by supplying it with a current which is associated with the phase error signal. The low-pass output of the filter 85 is fed to a voltage controlled oscillator (VC0) 86 as an oscillation control signal.
The output of VC0 86 is coupled, through a buffer amplifier 87, to a variable prescaler 88 which is adapted for predetermined division. The output of the prescaler 88 is further divided by the programmable counter 89 and, then, routed to the phase comparator 83. The division ratio of the prescaler 88 has two different stages which are selectively set up by a control counter 90.
A channel designating signal is fed from the CPU 5, Fig. 1, to a serial-to-parallel converter 91 to be thereby converted into parallel signals, the parallel signals being applied to the counters 89 and 90. Each of the counters 89 and 90, therefore, is loaded with a particular division ratio which is associated with the channel designating signal. Since the elements 81 to 91 constitute in combination a programmable phase locked loop (PLL), a signal whose frequency is associated with the channel designating signal which is applied the serial-to-parallel converter 91 appears on the output of VC0 86. The output -- 13 - ~31~9~8 of VCO 86 is also applied to a frequency multiplier 91.
The output of multiplier 92 is routed to the receiver 31, Fig. 1, through a buffer amplifier 93 and a band-pass filter 94.
The supply of power to the reference oscillator 81, charge pump 84, VCO 86, buffer amplifier 87, prescaler 88, multiplier 92 and buffer amplifier 93 is controlled by the ~X power switch circuit 9, Fig. 1. It is to be noted that a block demarcated by a dashed line in Fig. 8 and designated by the reference numeral 95 is implemented with a one-chip complementary metal oxide semiconductor (CMOS~.
Referring to Fig. 9, a specific construction of the RX power switch circuit 9 is shown. As shown, a PNP
transistor 91 has an emitter E and a collector C which are connected to the power switch 12 and the RX section 3, respectively. The base B of transistor 91 is connected to the CPU 5 via a resistor 93 and to the emitter E via a resistor 92. When the CPU 5 delivers a low level signal, the transistor 91 is rendered conductive resulting that power is fed to the RX section 3. Conversely, when the CPU 5 delivers a high level signal, the transistor 91 is turned off to interrupt the supply of power to the RX
section 3.
` Fig. 10 is a block diagram showing the receiver 31 which includes a field strength detector 60. The receiver is of a double superheterodyne type which per se is well i3~9~8 known in the art and, therefore, it will be briefly ~escribed hereinafter. A received signal coming in through the antenna duplexer 2 is applied to a first mixer 51 to be mixed down into a first intermediate frequency (IF) signal.
A local oscillation signal is fed to the mixer 51 from the receive frequency synthesizer 32, Fig. 1. The first IF
signal is propagated through a first IF ~and-pass filter 52 to a second mixer 53 which then mixes the input IF signal with a local oscillation signal fed from a local oscillator 54 so as to mix it down into a second IF signal. This second IF signal is passed through a second IF band-pass filter 55, then amplified by an IF amplifier 56, and then limited in amplitude by a limiter 57.
The output of limiter 57 is routed to a frequency discriminator 58 on one hand and to the field strength detector 60 on the other hand. The frequency discriminator 58 demodulates the second IF signal to produce an audio frequency (AF) signal which is applied to an AF circuit 59.
The AF circuit 59 includes an AF amplifier, a low pass filter (LPF) and others and delivers its output to the speaker 6 and CPU 5.
The field strength detector 60 includes an envelope detector 61 which is adapted to detect the envelope of the outputs of the limiter 51 by detecting those outputs. An analog-to-digital (A/D) converter 62 converts the levels of the envelope detected and feeds the resulting digital signal to the CPU 5.
- 15 - 131~
The supply of power to the first and second mixers 51 and 53, local oscillator 59, IF amplifier 56, limiter 57, frequency discriminator 58, AF circuit 59 and field strength detector 60 is controlled by the RX power swltch circuit 9.
In summary, it will be seen that the present invention realizes a vehicle-mounted telephone which is usable over a long time with a minimum of current consumption. This is because channel scanning is effected intermittently to search for a channel with an electric field even when the telephone is left in poor electric field environments, the power consumption thus being suppressed. Another advantage attainable with the present invention is that, since the intermittent channel scanning operation is interrupted for a predetermined period of time after the reception of data, there occurs no delay in response due to the intermittent operation even in those environments which suffer from sharp changes in electric field.
Further, the delay in response to an operator due to the intermittent operation is eliminated because, after any data has been keyed in, the intermittent operation is not performed until a predetermined period of time expires.
Claims (21)
1. A portable radio apparatus comprising:
a receiving section capable of being tuned to any of a plurality of channels;
a switch circuit for controlling supply of power from a battery to said receiving section;
a detector circuit for detecting strength of electric fields which are developed on said channels; and a control section connected to said receiving section and said switch circuit and constructed such that, in response to an output of said detector circuit, said control section executes channel scanning for tuning said receiving section sequentially to said channels while, at this instant, controlling said switch circuit to feed power continuously to said receiving section and, when no data has appeared on said channels within a first predetermined period of time during said channel scanning, executes saving scanning for repeating a cycle in which said channels are sequentially scanned by one round and, then, the scanning is interrupted for a second predetermined period of time while, at this instant, controlling said switch circuit to feed power to said receiving section in synchronism with said saving scanning.
a receiving section capable of being tuned to any of a plurality of channels;
a switch circuit for controlling supply of power from a battery to said receiving section;
a detector circuit for detecting strength of electric fields which are developed on said channels; and a control section connected to said receiving section and said switch circuit and constructed such that, in response to an output of said detector circuit, said control section executes channel scanning for tuning said receiving section sequentially to said channels while, at this instant, controlling said switch circuit to feed power continuously to said receiving section and, when no data has appeared on said channels within a first predetermined period of time during said channel scanning, executes saving scanning for repeating a cycle in which said channels are sequentially scanned by one round and, then, the scanning is interrupted for a second predetermined period of time while, at this instant, controlling said switch circuit to feed power to said receiving section in synchronism with said saving scanning.
2. A portable radio apparatus as claimed in claim 1, wherein said control section is further constructed such that, when data is received on any of said channels while said saving scanning is under way, said control section tunes and fixes said receiving section to said particular channel while con-trolling said switch circuit to feed power continuously to said receiving section.
3. A portable radio apparatus as claimed in claim 1, further comprising a keyboard connected to said control section for generating a key signal through a key switch, said control section, when received said key signal during said saving scanning, controlling said switch circuit to interrupt said saving scanning and resume said channel scanning while feeding power continuously to said receiving section.
4. A portable radio apparatus as claimed in claim 1, wherein said round of said channel scanning includes at least the steps of scanning all of said channels, storing, among said channels, a first and a second channel having, respectively, the strongest and the second strongest electric field; determining whether or not data is present on any of said first and second channels; taking in data if present on any of said first and second channels; and terminating said round of said channel scanning if no data is present on said first and second channels.
5. A portable radio apparatus as claimed in claim 2, wherein said channels include a first and a second channel group, said round of said channel scanning including the steps of: where said apparatus is set to a first status, scanning said first channel group; storing a first and a second channel of said first channel group having, respectively, the strongest and the second strongest electric field; determining whether or not data is present on any of said first and second channels; taking in data if present on any of said first and second channels;
scanning said second channel group if no data is present on said first and second channels; storing a third and a fourth channel of said second channel group having, respectively, the strongest and the second strongest electric field; determining whether or not data is present on any of said third and fourth channels; taking in data if present on any of said third and fourth channels; and terminating said round of said channel scanning if no data in present on said third and fourth channels.
scanning said second channel group if no data is present on said first and second channels; storing a third and a fourth channel of said second channel group having, respectively, the strongest and the second strongest electric field; determining whether or not data is present on any of said third and fourth channels; taking in data if present on any of said third and fourth channels; and terminating said round of said channel scanning if no data in present on said third and fourth channels.
6. A portable radio apparatus as claimed in claim 1, wherein said detector circuit comprises an envelope detector fox detecting an envelope of a signal which is outputted by an intermediate frequency (IF) stage of said receiving section, and an analog-to-digital (A/D) converter for converting the output of said envelope detector to a digital signal.
7. A portable radio apparatus as claimed in claim 1, wherein said switch circuit comprises a PNP transistor having an emitter and a collector which are connected to, respectively, said battery and said receiving section, a base of said transistor being connected to said control section.
8. A portable radio apparatus as claimed in claim 1, wherein said receiving section comprises:
frequency converting means for converting a received signal into an intermediate frequency (IF) signal in response to a local oscillation signal;
demodulating means for demodulating said IF signal into an audio frequency (AF) signal; and frequency synthesizer means responsive to a channel designating signal from said control section for changing an output frequency and delivering an output to said frequency converting means as said local oscillation signal;
said detecting means comprising detector means for detecting an envelope of said IF signal, and an A/D
converter means for converting the output of said detector means to a digital signal.
frequency converting means for converting a received signal into an intermediate frequency (IF) signal in response to a local oscillation signal;
demodulating means for demodulating said IF signal into an audio frequency (AF) signal; and frequency synthesizer means responsive to a channel designating signal from said control section for changing an output frequency and delivering an output to said frequency converting means as said local oscillation signal;
said detecting means comprising detector means for detecting an envelope of said IF signal, and an A/D
converter means for converting the output of said detector means to a digital signal.
9. A portable radio apparatus having an intermittent scanning function, comprising:
a radio section capable of being tuned to any of a plurality of channels;
a power switch for establishing and interrupting supply of power to said radio section;
means for, in a waiting condition, controlling said radio section to sequentially scan control channels while measuring reception levels on said respective control channels, tuning said radio section to one of said control channels which has the highest reception level and, if necessary, to another of said control channels which has the second highest reception level, repeating said channel scanning when no data is received, and interrupting supply of power to corresponding portions except for said radio section and a timer section by controlling said power switch when data is not received for a predetermined period of time;
means for resuming said channel scanning by feeding power to said portions, which have been disconnected from said radio section, at predetermined time intervals after the interruption of the power supply; and means for interrupting said saving scanning and executing said channel scanning instead, when a predetermined condition is reached.
a radio section capable of being tuned to any of a plurality of channels;
a power switch for establishing and interrupting supply of power to said radio section;
means for, in a waiting condition, controlling said radio section to sequentially scan control channels while measuring reception levels on said respective control channels, tuning said radio section to one of said control channels which has the highest reception level and, if necessary, to another of said control channels which has the second highest reception level, repeating said channel scanning when no data is received, and interrupting supply of power to corresponding portions except for said radio section and a timer section by controlling said power switch when data is not received for a predetermined period of time;
means for resuming said channel scanning by feeding power to said portions, which have been disconnected from said radio section, at predetermined time intervals after the interruption of the power supply; and means for interrupting said saving scanning and executing said channel scanning instead, when a predetermined condition is reached.
10. A portable radio apparatus as claimed in claim 9, wherein said predetermined condition is the reception of data or the entry of key input on an operating section.
11. A portable radio apparatus comprising:
receiving means capable of being tuned to any of a plurality of channels in response to any of a plurality of channels designating signals which are individually associated with said channels;
power switch means responsive to a control signal for feeding power to said receiving means;
decision means for deciding whether or not data is present on any of said channels to which said receiving means is tuned;
first means for, when an output of said decision means is indicative of absence of data on said channels, feeding said channel designating signals to said receiving means while switching said channel designating signals cyclically and sequentially;
second means for, when said first means has operated continuously for more than a predetermined period of time, feeding said channel designating signals to said receiving means cyclically and intermittently; and third means for feeding said control signal to said power switch means in synchronism with operation timings of said first and second means.
receiving means capable of being tuned to any of a plurality of channels in response to any of a plurality of channels designating signals which are individually associated with said channels;
power switch means responsive to a control signal for feeding power to said receiving means;
decision means for deciding whether or not data is present on any of said channels to which said receiving means is tuned;
first means for, when an output of said decision means is indicative of absence of data on said channels, feeding said channel designating signals to said receiving means while switching said channel designating signals cyclically and sequentially;
second means for, when said first means has operated continuously for more than a predetermined period of time, feeding said channel designating signals to said receiving means cyclically and intermittently; and third means for feeding said control signal to said power switch means in synchronism with operation timings of said first and second means.
12. A portable radio apparatus as claimed in claim 11, further comprising:
fourth means for, when said decision means has decided that data is present on any of said channels while said first means is in operation, fixedly applying one of said channel designating signals which is associated with said channel to said receiving means; and fifth means for applying said control signal to said power switch means in synchronism with operation timings of said fourth means.
fourth means for, when said decision means has decided that data is present on any of said channels while said first means is in operation, fixedly applying one of said channel designating signals which is associated with said channel to said receiving means; and fifth means for applying said control signal to said power switch means in synchronism with operation timings of said fourth means.
13. A portable radio apparatus as claimed in claim 11, further comprising:
key input means for producing a key signal when a key switch is operated;
fourth means for, when said key signal is received while said second means is in operation, disenabling said second means while enabling said first means; and fifth means for delivering said control signal to said power switch means in synchronism with operation timings of said fourth means.
key input means for producing a key signal when a key switch is operated;
fourth means for, when said key signal is received while said second means is in operation, disenabling said second means while enabling said first means; and fifth means for delivering said control signal to said power switch means in synchronism with operation timings of said fourth means.
14. A portable radio apparatus as claimed in claim 11, further comprising:
field strength detector means for detecting the strength of an electric field on said channel to which said receiver means is tuned; and fourth means for storing a predetermined number of said channels according to order of field strength and based on an output of said detector means;
said decision by said decision means as to whether or not data is present being effected on said predetermined number of channels stored only.
field strength detector means for detecting the strength of an electric field on said channel to which said receiver means is tuned; and fourth means for storing a predetermined number of said channels according to order of field strength and based on an output of said detector means;
said decision by said decision means as to whether or not data is present being effected on said predetermined number of channels stored only.
15. A portable radio apparatus as claimed in claim 14, wherein said predetermined number is two.
16. A portable radio apparatus as claimed in claim 11, wherein said receiving means comprises:
frequency converting means for converting a received signal into an intermediate frequency (IF) signal in response to a local oscillation signal;
demodulating means for demodulating said IF signal into an audio frequency (AF) signal; and frequency synthesizer means for changing an output frequency in response to said channel designating signal and delivering an output to said frequency converting means as said local oscillation signal.
frequency converting means for converting a received signal into an intermediate frequency (IF) signal in response to a local oscillation signal;
demodulating means for demodulating said IF signal into an audio frequency (AF) signal; and frequency synthesizer means for changing an output frequency in response to said channel designating signal and delivering an output to said frequency converting means as said local oscillation signal.
17. A method of scanning channels of a portable radio apparatus, comprising the steps of:
tuning a receiving section to any of a plurality of channels;
feeding power to said receiving section in response to a control signal;
deciding whether or not data is present on said channel to which said receiving section is tuned;
when data is not present on said channels, tuning said receiving section to said respective channels cyclically and continuously;
when said cyclic and continuous tuning operation has continued for more than a predetermined period of time, tuning said receiving section to said respective channels cyclically and intermittently; and feeding power to said receiving section continuously during said continuous tuning operation and intermittently during said intermittent tuning operation.
tuning a receiving section to any of a plurality of channels;
feeding power to said receiving section in response to a control signal;
deciding whether or not data is present on said channel to which said receiving section is tuned;
when data is not present on said channels, tuning said receiving section to said respective channels cyclically and continuously;
when said cyclic and continuous tuning operation has continued for more than a predetermined period of time, tuning said receiving section to said respective channels cyclically and intermittently; and feeding power to said receiving section continuously during said continuous tuning operation and intermittently during said intermittent tuning operation.
18. A method as claimed in claim 17, further comprising the steps of:
when data is present on any of said channels during said intermittent tuning operation, tuning said receiving section to said particular channel fixedly; and when said receiving section is tuned to said particular channel, feeding power to said receiving section continuously.
when data is present on any of said channels during said intermittent tuning operation, tuning said receiving section to said particular channel fixedly; and when said receiving section is tuned to said particular channel, feeding power to said receiving section continuously.
19. A method as claimed in claim 17, further comprising the steps of:
manually generating a key signal; and when said key signal is produced during said intermittent tuning operation, resuming said continuous tuning operation in place of said intermittent tuning operation.
manually generating a key signal; and when said key signal is produced during said intermittent tuning operation, resuming said continuous tuning operation in place of said intermittent tuning operation.
20. A method as claimed in claim 17, further comprising the steps of:
detecting strength of an electric field of said channel to which said receiving section is tuned; and storing a predetermined number of said channels according to order of field strength;
said step of deciding whether or not said data is present being effected on said predetermined number of channels stored only.
detecting strength of an electric field of said channel to which said receiving section is tuned; and storing a predetermined number of said channels according to order of field strength;
said step of deciding whether or not said data is present being effected on said predetermined number of channels stored only.
21. A method as claimed in claim 20, wherein said predetermined number is two.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3700887 | 1987-02-20 | ||
| JP37008/1987 | 1987-02-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1319958C true CA1319958C (en) | 1993-07-06 |
Family
ID=12485662
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000559465A Expired - Fee Related CA1319958C (en) | 1987-02-20 | 1988-02-22 | Portable radio apparatus having battery saved channel scanning function |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4977611A (en) |
| EP (1) | EP0279697B1 (en) |
| KR (1) | KR910008738B1 (en) |
| CN (1) | CN1014854B (en) |
| AU (1) | AU605245B2 (en) |
| CA (1) | CA1319958C (en) |
| HK (1) | HK84297A (en) |
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-
1988
- 1988-02-15 KR KR1019880001546A patent/KR910008738B1/en not_active IP Right Cessation
- 1988-02-19 EP EP88301444A patent/EP0279697B1/en not_active Expired - Lifetime
- 1988-02-19 US US07/158,210 patent/US4977611A/en not_active Expired - Lifetime
- 1988-02-20 CN CN88101334A patent/CN1014854B/en not_active Expired
- 1988-02-22 CA CA000559465A patent/CA1319958C/en not_active Expired - Fee Related
- 1988-02-22 AU AU12022/88A patent/AU605245B2/en not_active Expired
-
1997
- 1997-06-19 HK HK84297A patent/HK84297A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| EP0279697A2 (en) | 1988-08-24 |
| CN88101334A (en) | 1988-08-31 |
| EP0279697A3 (en) | 1990-11-14 |
| AU1202288A (en) | 1988-08-25 |
| US4977611A (en) | 1990-12-11 |
| EP0279697B1 (en) | 1995-04-26 |
| HK84297A (en) | 1997-06-27 |
| KR890013910A (en) | 1989-09-26 |
| CN1014854B (en) | 1991-11-20 |
| AU605245B2 (en) | 1991-01-10 |
| KR910008738B1 (en) | 1991-10-19 |
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| Date | Code | Title | Description |
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| MKLA | Lapsed | ||
| MKLA | Lapsed |
Effective date: 20030707 |