Suppressing idle tones in a delta-sigma modulator

A circuit including delta-sigma modulation, comprising:

• delta-sigma modulator circuitry, including
• an input interface to receive an analog input signal,
• modulator input circuitry coupled to the input interface to sample the input signal at an oversampling frequency, and to provide a modulator input signal based in part on the sampled input signal, and
• modulator loop circuitry to quantize the modulator input signal to generate a modulator output signal, the modulator loop circuitry to provide a feedback signal to the modulator input circuitry;
• and
• digital filtering circuitry to filter the modulator output signal to provide a digital output signal at a data rate frequency (fDR) related to the oversampling frequency by a defined oversampling ratio;
• and
• out-of-band (OoB) signal generator circuitry coupled to the modulator input circuitry to inject a deterministic OoB injection signal at a defined OoB frequency outside of a target frequency band;
• the modulator input circuitry to combine the sampled input signal, the feedback signal, and the OoB injection signal to provide the modulator input signal;
• and
• the digital filtering circuitry to filter the OoB injection signal.