IEEE Transactions on Acoustics Speech and Signal Processing · 1979 · 50 citations · 17 references
EngineeringSymmetry ConditionsBilateral ConversionMulti-rate Signal ProcessingCommunication CircuitTransmission SystemWeighting NetworkElectromagnetic CompatibilitySpeech RecognitionSpeech CodingFilter Bank24-Channel TransmultiplexerHealth SciencesElectrical EngineeringMultiplexingComputer EngineeringMulti-channel ProcessingSignal ProcessingDigital AudioSpeech Processing
The design of a transmultiplexer capable of performing the bilateral conversion between one 1544 kbit/s digital signal (which represents 24 PCM coded voice channels) and two analog group signals (each one containing 12 voice channels in the 60-108 kHz band) is investigated. It is shown that an FIR filter bank required as part of such a transmultiplexer can be realized efficiently by cascading a discrete cosine transform processor and a weighting network. Fast convolution algorithms are derived for evaluating the cosine transform. A method of using the symmetry conditions to reduce the computation rate in the weighting network and an elegant hardware configuration for implementing it are also discussed.
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