UMTS/HSPA Module Series
WCDMA UGxx Audio Design Note
WCDMA_UGxx_Audio_Design_Note Confidential / Released 22 / 56
1. Horizontal axis is frequency, longitudinal axis is distortion and unit is %.
2. In Figure 15
, the three colors represent three venders’ products. After comprehensive comparison,
the green one performs the best, and the blue one is worse, and the red one is the worst.
4.6. Components of Microphone
It is recommended to use an electret microphone with a sensitivity of -42±3dB/Pa @ 2V
(not less than
-44±3dB) and impedance of 2.2Kohm. If RF TDD noise is detected at the MIC, please contact MIC vendor
for product with better RF suppression capability. Furthermore, the microphone channel circuit can be
optimized to decrease TDD issue at MIC side.
NOTE
Quectel
Confidential