A digital signal processing apparatus for frequency multiplexing and demultiplexing of narrow band FDM signals has a first block fine processing stage (11) connected in series to a first block coarse processing stage (16, 17) and in parallel therewith a second block fine processing...http://www.google.com.au/patents/US5699363?utm_source=gb-gplus-sharePatent US5699363 - Digital signal processing apparatus
