The application of delta-sigma ADCs to V32 modems

The CS5317 CMOS integrated circuit from Crystal Semiconductor provides a delta-sigma converter tailored for V.32 receivers. The CS5317 delta-sigma converter contains a 2 MHz, 1-bit ADC followed by a digital FIR filter to provide a 16-bit, 20 kHz output. The combination of oversampling and digital filtering greatly eases antialias requirements. Thus, the CS5317 offers 84 dB dynamic range and 80 dB total harmonic distortion, at a fraction of the cost of hybrid and discrete solutions. An on-chip phase-lock loop simplifies the CS5317´s use in applications where the output word rate must be locked to an external sampling signal