U 920A

PDM Signal Conditioner
The U 920A dual-channel model uses independent demodulation chips, offering lower background noise and faster hardware response. It supports voltage and clock adjustment (via serial port control). The output uses BNC connectors with analog signals, making it convenient for use with data acquisition cards.

Product Parameters

Product Parameters
PDM conditioning channels	2
Input interface	EDGRM-3.81-8P
Output interface	BNC
Input-output conversion ratio	1%FS=5mVrms, 10%FS=50mVrms, 20%FS=100mVrms, 50%FS=250mVrms, 100%FS=500mVrms
Supported microphone power supply（DC）	1.2V, 1.5V, 1.8V, 3.3V
Supported microphone clock （Hz）	768K, 800K, 812.5K, 1.2M, 1.536M, 2.4M, 3.072M, 3.25M
Product dimensions (mm)	1409633
Output mode	Single-ended output
Net weight(kg)	0.35
Package dimensions(mm)	25016565
Package weight(kg)	0.52
Operating temperature	-20℃ - 50℃
Operating voltage	DC 5V(USB-B)
Typical power	1W
Full-load power consumption	3W
Communication mode	Serial Communication

PDM Demodulation Channel

PDM Demodulation Channel
Sampling rate range	12kHz - 50.78kHz
Sampling rate interpolation	x64

Channel Asynchronous Mode Single-Point Metric：

Idle Channel Noise (uVrms)
Sampling Rate	fs=48kS/s
Typical value	≤14
Maximum	15
Test Conditions: [1] Output source: APx525-PDM module; DAQ card: APx525-AI module (UNBAL) [2] U 920A voltage setting: 3.3V; Clock setting: 3.072 MHz; Asynchronous mode [3] Output source signal level: -144 dBFS; filter settings: No weighting, no EQ, 10 Hz high-pass filter

THD (dB)
Sampling Rate	fs=48kS/s
Typical	≤-79
Maximum	-78
Test Conditions: [1] Output source: APx525-PDM module; DAQ card: APx525-AI module (UNBAL) [2] U 920A voltage setting: 3.3V; Clock setting: 3.072 MHz; Asynchronous mode [3] Output source signal level: -144 dBFS; filter settings: No weighting, no EQ, 10 Hz high-pass filter

THD+N (dB)
Sampling Rate	fs=48kS/s
Typical value	≤-78
Maximum	-77
Test Conditions: [1] Output source: APx525-PDM module; DAQ card: APx525-AI module (UNBAL) [2] U 920A voltage setting: 3.3V; Clock setting: 3.072 MHz; Asynchronous mode [3] Output source signal level: -10 dBFS 1kHz; filter settings: No weighting, no EQ, 10 Hz high-pass filter

SNR（dB）
Sampling Rate	fs=48kS/s
Typical value	≥94
Minimum	93
Test Conditions: [1] Output source: APx525-PDM module; DAQ card: APx525-AI module (UNBAL) [2] U 920A voltage setting: 3.3V; Clock setting: 3.072 MHz; Asynchronous mode [3] Output source signal level: 0 dBFS 1kHz; filter settings: No weighting, no EQ, 10 Hz high-pass filter

Channel Synchronous Mode Single-Point Metric：

Idle channel noise(uVrms)
Sampling Rate	fs=48kS/s
Typical value	≤14
Maximum	15
Test Conditions: [1] Output source: APx525-PDM module; DAQ card: APx525-AI module (UNBAL) [2] U 920A voltage setting: 3.3V; Clock setting: 3.072 MHz; Asynchronous mode [3] Output source signal level: -144 dBFS; filter settings: No weighting, no EQ, 10 Hz high-pass filter

THD (dB)
Sampling Rate	fs=48kS/s
Typical value	≤-78
Maximum	-77
Test Conditions: [1] Output source: APx525-PDM module; DAQ card: APx525-AI module (UNBAL) [2] U 920A voltage setting: 3.3V; Clock setting: 3.072 MHz; Asynchronous mode [3] Output source signal level: -144 dBFS; filter settings: No weighting, no EQ, 10 Hz high-pass filter

THD+N (dB)
Sampling Rate	fs=48kS/s
Typical value	≤-77
Maximum	-76
Test Conditions: [1] Output source: APx525-PDM module; DAQ card: APx525-AI module (UNBAL) [2] U 920A voltage setting: 3.3V; Clock setting: 3.072 MHz; Asynchronous mode [3] Output source signal level: -10 dBFS 1kHz; filter settings: No weighting, no EQ, 10 Hz high-pass filter

SNR（dB）
Sampling Rate	fs=48kS/s
Typical value	≥94
Minimum	93
Test Conditions: [1] Output source: APx525-PDM module; DAQ card: APx525-AI module (UNBAL) [2] U 920A voltage setting: 3.3V; Clock setting: 3.072 MHz; Asynchronous mode [3] Output source signal level: -10 dBFS 1kHz; filter settings: No weighting, no EQ, 10 Hz high-pass filter

Channel Asynchronous Mode Sweep Metrics：

Frequency Response


Test condition : [1]Output source APx525-PDM module DAQ Unit APx525-AI module UNBAL [2]U 920A voltage setting :3.3V clock setting :3.072MHz asynchronous mode [3]Output source signal 20%FS 20~20kHz acquisition filter settings no weighting no EQ 10Hz high-pass filter

Channel Synchronous Mode Sweep Metrics：

Frequency Response



Test condition : [1]Output source:APx525-PDM module DAQ Unit APx525-AI module UNBAL [2]U 920A voltage setting :3.3V clock setting :3.072MHz synchronous mode [3]Output source signal 20%FS 20~20kHz acquisition filter settings no weighting no EQ 10Hz high-pass filter