There are two square waveform which frequency are nearly 100MHz and 99MHz, I want to acquire the difference frequency of these two wave (about 1MHz) . So how to do to realize such schedule and which chips should be used?
You can use a mixer to find the difference frequency. Drive one signal into the LO and drive the other into RF. Then low pass filter the output and you'll have the difference frequency.
Thank you for your reply. But generally, the LO and RF ports of mixer need to be sine waveform . what I get is square waveform. And It is better to be square waveform at the output port IF of the mixer. I wander whether has a digital frequency mixer that can meet this acquirement.
The LO typically can be driven with either a sinewave or a square wave. A square wave often will have been jitter because of the high order harmonics.
The RF can be driven with whatever the signal of interest is. It can be a square wave, CDMA, GSM, OFDM, etc.
Another way to find the difference is to drive both signals into an ADC and calculate the difference in the digital domain with an FPGA.
You could also do it with phase frequency detector (PFD) which would give you an output for the frequency difference.
Retrieving data ...