Audio Precision AP 517, Installation Instructions Manual

Page: 75 / 92

APx PDM I/O Module for B Series: Specifications 73
PDM
PDM input/output module
specifications
with APx500 v5.0 or higher measurement software
as fitted in APx52x, 555 and 58x B Series audio analyzers
NP0020.00036 rev 002
March 2020
This illustration shows the PDM module, model 236.
The PDM option provides a complete solution for addressing circuits or devices with a PDM
input or output. The PDM signal output consists of an APx generator audio signal, interpolated
by a broad choice of oversampling ratios, and modulated into a 1-bit PDM bitstream. A 4th-
order modulator is the default; a 5th-order modulator can be selected. The PDM Option also
provides a signal input with its associated clock connection. The input accepts a 1-bit PDM bit-
stream, which is then decimated by one of a wide range of decimation ratios and filtered into
baseband audio at the Decimated Rate. The input bitstream can also be analyzed directly
(before decimation) in the Signal Analyzer to view out-of-band components.
These specifications cover the digital input and output functions of the Audio Precision PDM
interface for the current version, model 236.
PDM specifications begin on the next page.