Created on 2013-12-17 00:18:00
APx PDM Line Driver
The AP PDM Line Driver solves a key problem encountered when testing PDM MEMS (Micro Electro-Mechanical Systems) microphones: the distance between the DUT and the analyzer itself.
PDM data is one-bit oversampled audio, most commonly employing a oversampling factor of 64. This means that in order to represent the performance of a PCM audio system with a 48kHz sample rate, many digital MEMS microphones employ a sample rate of 48kHz x 64 = 3.072MHz. The low-power, current-limited design of MEMS devices means that this high-frequency signal can suffer severe degradation due to cable capacitance in many test bench configurations, especially where the DUT must be a substantial distance - 1 meter or more - from the analyzer.
Testing microphones in an anechoic chamber is just such a scenario. All noise-generating equipment (PCs, analyzers) must remain outside the chamber, requiring substantial cable runs from the inside.
AP PDM Line Driver with cables
The Audio Precision PDM Line Driver provides a buffer for the PDM audio data, allowing cable lengths of up to 45ft (13.7m) to be used between DUT and analyzer with no loss or alteration of the digital signal.
