SIGNAL MODULATION CIRCUIT

摘要

Provided is a modulation circuit that can correct an output state in real time and reliably modulate an input signal to output the modulated signal. The signal modulation circuit includes a subtractor, an integrator, a chopper circuit, a frequency divider, and a D-type flip-flop. A delay circuit of a sigma delta modulation circuit is not provided to a feedback circuit, and a signal is delayed and quantized in the D-type flip-flop. The chopper circuit inserts a zero level at timing synchronized with a clock signal, so that pulse density modulation is performed.

主权项

1. A signal modulation circuit for performing delta sigma modulation on an input signal in synchronization with a clock signal to output the modulated signal, the circuit comprising:
a subtractor for calculating a difference between the input signal and a feedback signal; an integrator for integrating an output signal from the subtractor; a zero level inserting circuit for inserting a zero level into the signal integrated by the integrator at timing synchronized with the clock signal; a quantizer for delaying the signal output from the zero level inserting circuit and quantizing the delayed signal; and a feedback circuit for feeding back the signal quantized by the quantizer to the input signal.