Hi, my question may be too open ended in which case some help defining it would be helpful. The signal I wish to measure is estimated to be ~50 pico volts in amplitude generated in an HF AT-cut quartz crystal. Basically all the signal power will be at the fundamental mode resonant frequency (lets say 4MHz) of the crystal. I can control the signal source in that I know it's precise frequency and I can turn it off and on. I would like to measure the amplitude and phase of the received signal. Any suggestions would be welcome.