|This circuit block set provides building elements for a high performance 13-bit linear feature codec. As shown in the figure on left, a 2nd order analog S-D ADC first converts an analog signal to a 1-bit digital signal at the over-sampling frequency, i.e. 1024KHz. Then the 1 bit digital signal is converted to 13 bits digital signal at the Nyquist frequency (i.e. 8KHz) using certain digital filters. The D/A converter will change the 1-bit digital signal to an analog signal.