Why purpose crystal is added inside the usb to 3.5 mm audio jack .please explain how pcm2706 works ?

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Hi I am having some technical doubts on this
Inside pcm2706 ,they are using 12 MHz crystal .. how to crystal timing interact with usb data to processing to analog signal with human audible frequency and why we need External low filter . please help me on this Ivan SalaZar

Hi Sunil,

The 12M MHz signal is necessary for the DAC; it takes the digital audio data coming from the USB and converts it to analog audio.
The clock signal is also necessary for the PLL that is used to recover the audio clock from the USB packet data.
The external filter is a HPF that builds a BPF with the internal LPF.

Best regards,
-Ivan Salazar
Texas Instruments

Thanks Ivan ..