PDM Demodulator PDM to PCM Conversion IP

The PDM Demodulator converts high-rate digital-microphone PDM streams into PCM audio for downstream filtering, ANC and voice processing. A configurable cascaded integrator-comb filter provides selectable order, comb depth and decimation ratio. Output scaling, optional format conversion and shared channel control support low-power and low-latency audio integration.

PDM Demodulator Specifications

The approximately 192 dB range associated with 32-bit Q31 is a theoretical numeric range, not measured SNR. Actual signal quality depends on the input microphone, filter configuration, scaling and system noise. Reference power and minimum delay are not a single universal operating point.

Availability and validation

• PDM input from 0.192 to 6.144 MHz; PCM output up to 768 kHz.
• CIC order up to 8, comb depth of 1 or 2 and decimation ratio up to 128 in the reference configuration.
• Configurable PCM word width, up to 32-bit Q31 numeric output, with output scaling.
• Up to 32 channels with synchronized start, stop and reconfiguration through APB control.
• Optional multibit PDM support, fixed-to-FP32 conversion and physical PDM interface.

Programmable CIC parameters trade group delay, filtering and numeric headroom for the selected microphone and rate. A linear-phase response preserves relative timing through the filter, while synchronized channel control supports correlated microphone paths. Direct PCM output simplifies connection to downstream signal processing.

Digital-microphone front ends, earbuds and AI glasses, ANC and transparency input paths, multichannel audio acquisition, and low-power voice capture.