PCSU1000 frequency resolution

Before buying the PCSU1000, I would like to be sure that I can use it to performed the FFT of a signal with a resolution of 0.1 Hertz at 7 MHz.


This requires a $10.000 instrument
Sorry, not in our range.

What is the appication? 0.1 Hz FFT resolution at 7 MHz requires 140 Meg of capture memory. Actually even typical $10000 scopes don’t have anywhere near that amount. Maybe it’s time to re-think your approach; one option would be to use a mixer to downconvert the 7 MHz signal to a lower frequency range which can then be sampled at a lower frequency so the FFT has finer resolution (and the PCSU can do that). E.g. to analyze the spectrum between 6.95 MHz and 7.05 MHz, set the local oscillator (i.e. the second input signal into the mixer) to 6.95 MHz - the 6.95…7.05 MHz spectrum is then downconverted to 0…100 kHz, and you only need 2MB of capture memory for a 0.1 Hz frequency resolution.

If it is necessary to get a broader range of the actual input spectrum then just step the local oscillator frequency and repeat for each step, then stitch the FFTs together.


+1, even the $80k+ Lecroy WaveMaster 8 series, which can have a 512Mpts/ch capture, only uses 120Mpts for the FFT analysis…