:::::about subSAMPLE issue

[jeffsky520]

:!::!:
In my measurement of chip, 47MHz signal is applied to S/H circuit with sample rate of 50MHz, 3MHz signal is wanted, but there is also a 22MHz signal occurs, WHY
? Looking forward to your sincere reply . thanks.

 

[zyzyh]

In sampling,the sampling clock can be looked as LO. And all mixed signal appear 0~Fs/2.
So,
47+/-50=-3/97 MHz
97-75=22MHz

I wish it's useful for you!