Other Parts Discussed in Thread: RFSDK, ADC14X250
As we are coming up to speed with the K2L RFSDK and the DFE, we purchased an ADC14X250 eval board to experiment with and learn from. We do not use the DAC and timing interface boards from the reference design.
We are using the RFSDK and the Reference Design "Optimized Radar System Reference Design Using a DSP+ARM SoC", together with RFSDK use case 1x1-1xLTE80-HC-JESD121121x-DEMO2.
Our EE team wired clocks from the K2L eval board to the ADC board, and we get JESD communication from the ADC to the K2L. We are using an external signal generator to feed the ADC.
We can adjust the signal generator frequency around 61.44Mhz and then look at the RFSDK web page, and we see exactly what should be there.
However, the actual signals we care about are substantially lower than the 61.44MHz carrier frequency that is built into the reference design.
We have a data stream that is in the ballpark of 2Mhz in frequency.
When we adjust the frequency of the signal generator, we get discernible signals and FFT frequencies down to about 5Mhz, but below that we just get more and more noise. At 2MHz, there is just noise, no useful frequency information at all.
Is there a way to re-configure the Keystone so that it uses a lower-frequency carrier? Or perhaps bypass the demodulation completely?
Ideally, we would like to set the keystone up to do a 2Mhz carrier.
However, if we need to, we can post-process the signal to some extent in DSP code.
But currently, the IQ pairs we see in the DSP have no useful information that we can try to use when the inputs are in the vicinity of 2MHz.
Is the only way to do this to create an updated DFE configuration file? I.e., with help from Azcom or another external consultant?
Is there perhaps an "easy" part of the DFE configuration file that we could try to adjust ourselves?
Or is there a function call down inside the PDK drv/dfe or drv/iqn2 directory that we can call to make this adjustment? Or perhaps configuration settings that can be changed from the python RFSDK code?
Thanks in advance,
Greg Johnson
