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Re: T41 Hilbert Filter Design


 

On Fri, May 23, 2025 at 06:20 AM, Albert Peter wrote:
I will have to have a look. I did revise some of the fitlter designs in the last version.
I tracked down a problem I was having in SSB transmit to the size of the decimate state vectors, FIR_dec3_EX_I_state, FIR_dec3_EX_Q_state.? If these are allocated to DMAMEM, the RF out on the RF board at times exhibits a raised skirt in both side bands.??I'm a novice in filter design and use, but it appears the FIR_dec3_EX_I_state and FIR_dec3_EX_Q_state are too small. ?Properly sized this doesn't happen.? The FIR_int3_EX_I_state and FIR_int3_EX_Q_state vectors appear to be too big, but this isn't a problem, except more memory is used.?
?
How to reproduce:
  • FIR_dec3_EX_I_state and FIR_dec3_EX_Q_state in DMAMEM, compile v66-9 with "Faster with LTO", PTT sometimes gives raise sideband skirt in signal out from RF board.
  • Also, compile v66-9 with "Smallest Code", PTT causes a crash.

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