Audio Precision APx-PDM

Pulse Density Modulation (PDM) is a one-bit, high rate data stream that conveys a signal by modulating the density of the pulses. Applications for PDM include Micro-Electrical-Mechanical System (MEMS) microphones found in smartphones, and integrated circuits with PDM interfaces.The APx PDM option provides direct connectivity for audio devices that have a PDM output (such as a MEMS microphone) or input (such as the decimator on a smartphone chip). In addition to all the standard audio measurements, APx provides variable DC voltage, variable sample rate, and a PSR (power supply rejection) measurement to test the device’s full operating parameters. PDM (mono or stereo) can be selected for both the analyzer inputs and outputs simultaneously, or PDM can be paired with any of the other available I/O formats: analog (bal/unbal), AES or S/PDIF digital, Bluetooth, HDMI, or serial digital. Over 30 one-click audio measurements may be made, either individually or in an automated project. Features include weighting filters, and user defined high and low pass filters, 1.2M point FFTs, real-time oscilloscope monitoring, custom reports, statistical calculations, and quasi-anechoic acoustic measurements.