#### Maitry07

##### Advanced Member level 4

My main requirement is to use I/Q sampling on the RF input (sine wave) using the direct digitization method and convert these cartesian data into polar form to generate the amplitude using the formula of sqrt(I^2+Q^2). I am using FPGA for this implementation.

RF input's highest frequency component is 60 MHz (sine wave, no modulation) . I am using oversampling to generate I, Q samples using DDC algorithm along with the decimated filter to generate the I, Q samples. right now my I, Q samples data rate after decimation is 61.44 MSPS.

If I provide this much of high sample rate results to generate the amplitude without averaging, I am getting the different samples at the output of which If i am doing averaging, I am able to get the stable amplitude output.

so, what I am understanding from the study and other application notes that there is a requirement of averaging such as moving averages to get stable result. so when we do the averaging, the output sample rate after averaging will be reduced. So below are my queries.

1. As the CIC filter is equivalent to the moving average, as CIC is the RRS filter while moving average is the non recurrsive averaging filter. so, which one is more suitable?

2. As my input RF signal is pure sine wave, what should be the suitable averaging factor should I use to get the accurate and stable amplitude measurement? My input sine wave is clean and with less harmonics.