Data level fault tolerance in demultiplexer filter banks

An efficient method for demultiplexing frequency slotted channels employs multirate filter banks which contain fast Fourier transform processing. All numerical processing is performed at a lower rate commensurate with the small bandwidth of each baseband channel. The paper demonstrates methods for protecting the integrity of the demultiplexing operations by using real number convolutional codes to compute comparable parity values which detect errors at the data sample level. High-rate, systematic convolutional codes produce parity values at a much reduced rate, and protection is achieved by generating parity values in two ways and comparing them. Parity values corresponding to each output channel are generated in parallel by a subsystem, operating even slower and in parallel with the demultiplexer that is virtually identical to the original structure. These parity calculations may be time-shared with the same processing resources because they are so similar