Version 6-1097 COH2 chuffing in frequency domain mode (1)

[rsku...@gmail.com]

I have been doing some testing on version 6-1097 and I see some chuffing in COH2 mode in the frequency domain (1) butt no chuffing and normal operation in the time domain mode (2). 

None of this appears tp be affected by gain or the AGC being in normal or in COH mode.

Version 5.03 works normally and does not exhibit this behavior.

So something is going on with COH2 in version 6-1097.

Rick Kunath, K9AO

[Leif]

Hi Rick,

I do not understand what you mean by "chuffing", but there should(?) be
no difference between 5.03 and later versions.

Resampling in the frequency domain means make an fft, reduce the size and
transform back to the time domain. This is very efficient for wide filters
and allows the placement of notches in the passband. It is however
sensitive to what parameters you choose.

I suggest you try the same parameters in 1097 that you used in 5.03.

first fft bandwidth
if you have not selected second fft:
first fft window
else
first backward fft att. N
second fft bandwidth factor
second fft window
second forward fft att. N
endif
first mixer bandwidth reduction

If any of those differs, that may make the back transformed smaller
size transforms not match each other perfectly. I do not remember
the details. You might try in 5.03 to provoke mismatch of the back
transforms. I do not have any system to try myself right now, but
you should be able to find fairly quickly.

73

Leif

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[Earl Shaffer]

HI Rick.

What do you see when you look at CPU usage?

Perhaps something is hogging the CPU.

Earl.

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[Rick Kunath]

Thanks Earl.

That's what I thought too but it's loafing along, no satriurated cores either.

Leif hit it. I compared the par files from the 5.03 version and the latest 6 version, and then I changed the settings on V6 to what I have for V5 and the issue went away.

I had done a completely fresh setup on V6 and thought I had answered as I did for 5, but clearly I must have had to switch up some of the parms a while ago.

Rick Kunath, K9AO