Successive approximation register (SAR) analog-to-digital converter (ADC) having optimized filter

摘要

A system such as a mechanically tuned radio can have a signal path to receive and process an incoming radio frequency (RF) signal and to provide the processed signal to a first analog-to-digital converter (ADC) to convert the processed signal to a digital signal and to digitally demodulate the digital signal to obtain an audio signal, where this first ADC is separate from an auxiliary ADC not part of the signal path.

主权项

1. A system comprising:
a variable impedance controllable by a manual tuning mechanism to provide an analog signal; and an analog-to-digital converter (ADC) coupled to the variable impedance to receive the analog signal, the ADC including: a comparator to compare the analog signal received at a first input with a feedback signal received at a second input; a successive approximation register (SAR) coupled to the comparator and having N-bits of resolution, wherein the SAR is to update a bit of an N-bit output based on the comparison; a delta-sigma modulator (DSM) coupled to the SAR to receive the N-bit output of the SAR and to generate an output; and a digital-to-analog converter (DAC) coupled to the DSM to convert the output to the feedback signal; and a low pass filter (LPF) to filter and output the feedback signal to the second input of the comparator.