Synthesis of Digital Attenuators for Segment-Companded PCM Codes

Segment companding laws are being used in PCM channel banks to permit more efficient signal processing on a digital basis. A unified formulation of these companding laws is used as a basis for the systematic synthesis of digital attenuators operating directly on the compressed code. Simple sequential circuits for digital attenuation are derived from expansion and compression algorithms. Signal-to-noise ratio, idle-circuit noise, and attenuation actually achieved are calculated.