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i.MX6 Quad | Audio Record can't recording high frequency voice ( > 8KHz )

Question asked by Rick Chu on Apr 20, 2015
Latest reply on Oct 12, 2017 by oway

Hi,

 

We have an issue with audio recording on i.MX6 Quad Core Platform. The hardware is made by our self (based on SABRESD board), and running Android 4.4.2 (BSP based on android_kk4.4.2_1.0.0-ga).

When the audio source frequency higher than 8 KHz, we can't record any data with our device.

We have confirmed that Microphone can received high frequency (at least 20 KHz) and audio chip (ALC5640) also can record  from 8 KHz to 96 KHz data no problem (tested with audio EVB).

The audio chip vendor mention that the limitation may caused by freescale i.MX6, but we have not see any discussion about this topic on support forum.

 

Have any one have such experience to record high frequency audio on i.MX6 platform? Our requirement is to support 18 KHz~ 20 KHz audio record for audio payment solution.

 

Our hardware information list on below:

CPU: i.MX6 Quad Core

Audio: Realteak ALC5640-VB

Microphone: Digital Microphone

Android Version: android_kk4.4.2_1.0.0-ga

I2S clock

MCLK : 11289600Hz

BCLK : 1411200Hz

LRCLK: 44100Hz


Rick

 

7KHz source is okay

7KHz.jpg

 

8KHz source is NG

8KHz.jpg

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