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TOPIC: cw peak filter

cw peak filter 18 Apr 2016 06:00 #1

  • pa5fn
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Hi, maybe its possible to make an audio peak filter for cw,
now i do it by using the eq - all sliders on minimum and 700Hz on +7.
but it would be nice to have a narrower peak and maybe with narrow/mid/wide/ pitch and level settings

73's hans
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cw peak filter 22 Apr 2016 17:06 #2

  • VassiL
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Hi Hans!
Why you need Eqializer for CW ?
Just choose CW Mode and set 20, 50, 100 Hz filter bandwidth. Also you can change pitch and other parameters of the CW signal in the menu - Arrow near BreakIn button on front panel, or SPEED button near CW Speed slider on front panel of the software.
Narrow filter has peak amplitude frequency characteristic - you no need EQ for CW mode, set 0dB for all RX EQ bands..
Василий, Vasily,
Expert Electronics
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cw peak filter 23 Apr 2016 03:59 #3

  • pa5fn
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Hi Vassil, well my hearing is not so good, and peaking the cw frequency helps when copying weak signals and using the narrow cw filter and raising volume helps al lot also.

73's hans
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cw peak filter 23 Apr 2016 06:54 #4

  • pa5fn
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here is a mp3 , i switch eq on and off for me with eq is a little bit better
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cw peak filter 25 Apr 2016 06:16 #5

  • VassiL
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pa5fn wrote:
Hi Vassil, well my hearing is not so good, and peaking the cw frequency helps when copying weak signals and using the narrow cw filter and raising volume helps al lot also.
73's hans
Hi Hans,
Copying CW signals with narrow filters.
You can see two pictures below. Pitch: 700 Hz. Filter BW: 50 Hz. Cpecial for you showed all frequencies from 20Hz to 20kHz.
1. 50Hz filter without signals, only air noise. You can see very narrow Amplitude Frequency Characteristic(AFC). Out of 50 Hz bandwidth all signals and noises rejected more than 75-100 dB.

50Hz_RX_AmpFreqChar.png



2. 50Hz filter with CW signal in the center of this filter.

50Hz_RX_CW_signal.png


And my question - Is it not looks like peak filter?


3. No? Ok, lets look to the 20Hz bandwidth filter without CW signal - may be this filter looks like peak filter. I think you never find the peak filter which will be more peaky than our 20-50 Hz filters... because narrow filters has peak Aplitude characteristics.
If it's not enough you can increase RX CW filters taps - up to 7000 from default 1537 - filter will be more peakier (Options-Device-DSP-Filter-Filter Taps-CW).

20Hz_RX_AmpFreqChar.png


If you want make it more peak - you can you EQ. You can adjust it and save to profile CW peak EQ. And make usual SSB profile with usual EQ settings and make fast operations between these profiles.
Василий, Vasily,
Expert Electronics
Last Edit: 25 Apr 2016 06:34 by VassiL.
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cw peak filter 25 Apr 2016 20:12 #6

  • pa5fn
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Hi Vassil well it looks like a perfect peak filter,
i'm going to play around with the settings as you suggested ,tnx.
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cw peak filter 28 Apr 2016 09:03 #7

  • VassiL
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Hans, thank you for your idea.
After analysis was added APF function to CW mode. CW with 250Hz filter bandwidth and wider now works better with APF.
Also was added new DSE function.
New version can be downloaded in this forum by the folowing link.
Василий, Vasily,
Expert Electronics
Last Edit: 28 Apr 2016 09:03 by VassiL.
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cw peak filter 28 Apr 2016 17:26 #8

  • pa5fn
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Hi Vassil, thanks :yahoo:
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cw peak filter 28 Apr 2016 19:13 #9

  • pa5fn
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Tonight heard vy weak stations from JA (abt 18:30 utc) on 40 meter , the apf worked verry well
thanks again
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