How to generate the clock signal when using digital microphone

[Min 0 1]

Hi, I am trying to use some digital microphones to capture the voice. The problem is that the extension board seem did not to generate the clock signal. When I use an extra signal generator to link with the digital microphone, I can see the development board received some sound signals. However, when I use the clock pin on the extension board, there is nothing generated. I also used the oscilloscope to check the pin output, there seems just some noise.