Patent ID: 7936742

Claim:
A digital signal demultiplexing apparatus for demultiplexing a received signal including a plurality of signals that are frequency-multiplexed to output demultiplexed signals, comprising: a demultiplexing filter bank part including a configuration in which unit demultiplexing filter banks are connected in a multistage manner, each unit demultiplexing filter bank including one or more filters for filtering a first input signal and a down-sampler for down-sampling an output signal of each filter to output a down-sampled signal; and a frequency conversion and decimator part configured to receive at least one of the output signals of each unit demultiplexing filter bank, wherein the frequency conversion and decimator part includes a frequency conversion part, for each second input signal, configured to shift a frequency of the input signal and output a shifted signal, and one or more decimator parts serially connected to an output of the frequency conversion part, and at least one of the decimator parts includes a filter for performing band limitation of a filter input signal and a down-sampler for down-sampling an output signal of the filter and outputting a down-sampled signal, and the frequency conversion and decimator part receives the second input signal that is arranged in one of frequency bands fixedly divided by the demultiplexing filter bank part, and outputs a signal that straddles a boundary of the divided frequency bands, the frequency conversion and decimator part receiving the second input signal, which is output from a unit demultiplexing filter bank that is placed at a last stage among unit demultiplexing filter banks through which the signal that straddles the boundary pass.