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strath-sdr / rfsoc_frequency_planner

An RFSoC Frequency Planner developed using Python.
BSD 3-Clause "New" or "Revised" License
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Should we rank the harmonic No. using a top-down order? #5

Open liubenyuan opened 2 years ago

liubenyuan commented 2 years ago

Hi, when we use the frequency planner, the harmonics 1 or 2 has the most noticeable power and affect the final performance, should we reorder the yaxis to rank the harmonics No. from smaller values to bigger values?

jogomojo commented 2 years ago

The reason why we used this order was to keep compatibility with the original MS Excel-based tool by Xilinx, which this tool is based on. My worry with changing it is that someone mistakes the y-axis for amplitude rather than the order of the harmonics. I think for now it's best to keep things the way they are but it's something we might look into in the future.

liubenyuan commented 2 years ago

I am using the latest excel version of rfsoc frequency planner, and it look like this. I think the HDx harmonic No is correlated with the amplitude of the spurious, right?

2022-09-21_21-57 2022-09-21_21-57-2

jogomojo commented 2 years ago

Sorry for the late reply on this, I must have missed the notification. It is possible this was different in the original version, or I just got it round the wrong way when implementing it.

I just want to stress though that the y-axis has nothing to do with amplitude. HD2 and HD3 are typically the highest spurs within this context but it is not guaranteed because so many other factors are involved. The datasheet provides a reasonable guide on what amplitudes to expect for each type of spur, but direct measurement is the only way to find out how the spectrum will look for your specific board/setup.

For now we will keep things the way they are as this is an aesthetic issue. It's something we might revisit at a later date though.