Square-law companding apparatus based on nonlinear operations on modulated bit-stream

摘要

Disclosed are four independent circuits for compression, expansion, companding, and post-processing of a compressed delta-sigma bit-stream. Compression and expansion are based on the use of a second-order (or higher-order) delta-sigma modulator, and a nonlinear operation on a delta-sigma modulated bit-stream. Depending on application, the disclosed circuits can operate as a stand-alone integrated circuit, or as compandor apparatus as proposed. Inherited low-pass filter can be digital or analog. Thus, the only external analog component to the IC chip could be a capacitor C, when low-frequency analog signal is compressed or expanded.