This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TLV320AIC3104: output signal is attenuated depending on sampling frequency.

Part Number: TLV320AIC3104

Hi, I'm hyunwoo-kim . 

I'm set sampling frequency is 8kHz and 0dB gain mode.

and then input sine-wave with 1Vp-p by function generator. 

And I expected output signal is same with 1Vp-p sine-wave but there is not same by input frequency.

I get output signal same as input signal from 1kHz to 3kHz , but there is little bit attenuate output signal at 4kHz. 

I know that it can be recovered at 4kHz input signal at 8kHz sampling frequency by  nyquist sampling theory.

Could you explain why there is some signal attenuate at 4kHz with 8kHz sampling frequency ? 

Best Regards, 

  • Hi Hyunwoo Kim,

    The attenuation is related to the decimation filter's low pass response. The datasheet specifies the response only for 48 kHz operation. The response parameters are shown below, wherein there is a -17.5 dB attenuation at fs/2. Similar response can be expected for other sampling rates including 8 kHz.