DB4PLE
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Urgestein
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Re:neues Noise Reduction - Feedback
« Reply #60 on: 16. December 2017, 22:11:48 »
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Hi,
my analysis reveals the unfortunate but expected result: The problem is also in the digital data send out to USB. And is has exactly the frequency of the the speed. Before my recent changes to the spectrum code the problem was most likely already there but due to the previously somewhat indeterministic timing of the display updates harder to recognize in the normal noise. Now we clock the updates exactly and well, you can hear that especially with no antenna connected.
And it affects both parallel and SPI displays and both mcHF and OVI40 (I used an OVI40 UI with mcHF RF). It may be more pronounced with the mcHF UI board (can't tell) but it is not a mcHF specific issue.
73
Danilo
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PY3CRX_PY2PLL
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Re:neues Noise Reduction - Feedback
« Reply #61 on: 16. December 2017, 22:14:26 »
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Hi Danilo, I did what U had mentioned: listen USB audio.
It's the same I listen on speakers.
When we say sweep noise, in fact it's more like gaps than spikes.
Anyway, I'm aware abt processor limits. Still a GREAT project. QSD + SAM much comfortable to long listening periods BC-DX.
Time to build a case to this rig 
73
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Marcus Ramos
PY3CRX + PY2PLL
S B Campo - SP - BRA
GG66rf
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DB4PLE
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Urgestein
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Re:neues Noise Reduction - Feedback
« Reply #63 on: 17. December 2017, 17:56:08 »
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Hi Andreas,
how reproduced the issue:
- OVI40 UI + mcHF RF
- Dummy Load
- Spectrum Light On
- NR off or on
- AGC default settings, any AGC value
Switching between menu / no menu makes sound change obvious. And you can see it in the PC USB recording clearly.
73
Danilo
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DD4WH
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alter Hase
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Ich liebe dieses Forum!
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Re:neues Noise Reduction - Feedback
« Reply #65 on: 17. December 2017, 18:26:14 »
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Hi Andreas,
OVI40 + mcHF has the same noise, so it is not a question of ground loops in the ui board.
73 Frank
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-----------------------------------------
Teensy Convolution SDR
https://github.com/DD4WH/Teensy-ConvolutionSDR
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DB4PLE
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Urgestein
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Re:neues Noise Reduction - Feedback
« Reply #67 on: 17. December 2017, 19:45:30 »
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Hi,
I forgot: 80m shows highest volume of the effect. On higher bands not so pronounce or even inaudible.
73
Danilo
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peter_77
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THE mcHF and UHSDR forum !
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Re:neues Noise Reduction - Feedback
« Reply #68 on: 18. December 2017, 10:10:13 »
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Here is a video showing the noise effect.
First scene is NR on with Scope light ON and second is Scope light OFF.
You can clearly hear the sweeping noise with scope light enabled and also clearly the sound bursts when opening and closing the menues while scope light is off.
(Download file with a right click and rename it to "noise.mov" and open with VLC player or equivalent.
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 Noise-mov.txt
« Last Edit: 18. December 2017, 10:16:53 by peter_77 » |
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S53DZ
schon länger dabei
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Ich liebe dieses Forum!
 
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Re:neues Noise Reduction - Feedback
« Reply #70 on: 18. December 2017, 13:47:57 »
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Hi,
As it was already said, the only thing that really lowers or out-nulls the LCD refresh noise is putting the UI and RF boards of an mcHF 90° off.
http://lea.hamradio.si/~s53dz/arhiv/7-SDR/1-mcHF/1-mods/mcHF_90deg_inside.jpg
I maid the modification this way and the result concerning the noise was excellent. Of course, said that, one have to find a mechanical solution for the enclosure, ...
On the other UI board I have changed the LCD from SPI to parallel and that helps also a little.
73 Bojan
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S53DZ
schon länger dabei
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Re:neues Noise Reduction - Feedback
« Reply #72 on: 18. December 2017, 15:48:13 »
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But of course, Andreas,
As I said, my example was with the mcHF UI/RF and yours is with OVI/OVI boards! I believe you that you have solved some PCB layout troubles on OVI/OVI setup to get better results.
BTW, I am talking about small interference in audio at no signal at the antenna input and using headphones, whereas you, on the other side, are showing a video of a QSO and audio from the loudspeaker. Different things, don't you think?
73 Bojan
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DD4WH
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alter Hase
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Re:neues Noise Reduction - Feedback
« Reply #74 on: 10. January 2018, 21:47:07 »
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Michael DL2FW has implemented a new algorithm for the spectral noise reduction, which seems very promising, although still in alpha version.
Now we have three algorithms implemented for testing:
1.) Activate NR with the DSP box
2.) Choose algorithm in the debug menu (DEBUG menu -> NR Mode), the new one is called "Devel2"
3.) adjust parameters
4.) please report back your experience ! :-)
ADJUSTMENTS FOR DEVEL2 (noise estimation by MMSE following Gerkmann & Hendriks 2012)
* alpha = NR setting in DSP box = smoothing constant for SNRprio calculation
in DEBUG menu
* tax = smoothing time constant for noise power estimate (in milliseconds) [default: 72ms]
* tap = smoothing time constant for smoothed speech probability (in milliseconds) [default: 152ms]
* asnr = active SNR in dB [default 15dB]
* SNR prio min = minimum value for SNRprio estimator [default 15dB]
* all other NR settings are ignored by the devel2 algorithm
Sorry, the algorithm is quite complex now and behaves non-linearly, so I am not able to tell you anything about a "correct" setting. Please try and enjoy!
We would be very happy, if anybody could provide us with prefered settings and listening experiences !!!
WIKI:
https://github.com/df8oe/UHSDR/wiki/Noise-reduction
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-----------------------------------------
Teensy Convolution SDR
https://github.com/DD4WH/Teensy-ConvolutionSDR
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