Undersampling with the Red Pitaya
Posted: Wed Aug 02, 2017 8:53 am
Hi All,
I'm working on an FMCW radar that uses the Red Pitaya for control and as the ADC. I'm using the provided C API and a decimation factor of 8, to perform undersampling in the second Nyquist band.
As my signal increases past Fs/2 my signal amplitude begins to drop drastically. For example: a 10 MHz 2 Vpp signal appears as 0.8 Vpp once sampled. All my development work takes place in C and I have yet to fiddle with the FPGA. I'm wondering if the Red Pitaya applies some sort of digital frequency compensation based on the set decimation factor? And If I could disable or correct this?
Kind Regards
Darryn
I'm working on an FMCW radar that uses the Red Pitaya for control and as the ADC. I'm using the provided C API and a decimation factor of 8, to perform undersampling in the second Nyquist band.
As my signal increases past Fs/2 my signal amplitude begins to drop drastically. For example: a 10 MHz 2 Vpp signal appears as 0.8 Vpp once sampled. All my development work takes place in C and I have yet to fiddle with the FPGA. I'm wondering if the Red Pitaya applies some sort of digital frequency compensation based on the set decimation factor? And If I could disable or correct this?
Kind Regards
Darryn