Audio Precision has announced a PDM (pulse density modulation) I/O option for its APx500 audio analysers.
PDM is a 1bit, high clock rate data stream used with digital MEMS microphones which are used extensively in smartphone design. The PDM option allows the audio analyzers to connect directly to any device with a PDM input or output, enabling comprehensive testing of audio.
In addition to all the standard audio measurements, the PDM Interface provides variable DC supply voltage, variable sample rate, and a power supply rejection measurement to test the device's full operating parameters. PDM (mono or stereo) can be selected for both the analyser inputs and outputs simultaneously, and PDM can be paired with any of the other available I/O formats: analogue, AES, S/PDIF, Bluetooth, HDMI, or serial digital.
R&D engineers working on new digital MEMS designs can generate modulated PDM bitstreams and send them directly to decimation stages with no further conversion or hardware. Smartphone and tablet manufacturers working on new designs can interface directly with MEMS microphones and PDM decimation stages to tune and verify performance. A special acoustic response suite of measurements makes MEMS transducer testing fast, easy, and efficient, even in non-anechoic environments.
The analysers combine PDM with an integrated Bluetooth testing solution, low noise analogue for testing headphone outputs, digital serial (I²S) for direct chip-level communication, and HDMI for devices with HD video capabilities.
