US 10,972,123 B1 · Signal processing structure

Abstract

A signal processing structure and method are presented. A first digital filter operates on received sigma-delta modulated (SDM) input signals. A second pre-processing digital filter receives a SDM input signal, directly low pass filter the SDM input signal and provides an output SDM signal. The output sigma-delta modulated signal is provided as an input for said first digital filter. In standard digital systems operating with digital microphones, filtering of the microphones' output signal requires to first convert the signal into pulse code modulation (PCM), then filter and finally convert back to pulse density modulation (PDM). This approach increases the latency of the system because decimation and interpolation must be performed in order to pass from PDM to PCM. By using filters that operate directly on the oversampled PDM output of the digital microphones it is possible to reduce the latency of the system and minimize the hardware area.

Claims13

Dependent claims

A signal processing structure comprising:

a first digital filter configured to operate on received sigma-delta modulated input signals;
and
a second pre-processing digital filter configured to:
receive a sigma-delta modulated input signal, directly low pass filter the sigma-delta modulated input signal and provide an output sigma-delta modulated signal;
wherein said output sigma-delta modulated signal is provided as an input for said first digital filter.

2 more elements

Dependencies are inferred from the claim text.

Signal processing structure

Life of this patent

Signal processing structure

Life of this patent

Abstract

Claims13