DAX IQ Judder

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  • Updated 7 months ago
Hi I am having a problem with DAX IQ into CW skimmer, I get judder in the skimmer window, hard to describe what I mean so I have uploaded a small video to youtube with the issue, Anyone any ideas whats going on, I have 2 slices open they one with the judder is slice 2, but I often get it on slice 1 as well, I swapped to using IQ3 and it helps but not all the time, PC is a I5 and with everything  I use open I'm running at about 50% usage so I dont think its a PC resource issue,

Its not a great video as of course it wont do it badly when I have the camera on, the skimmer window on the right is the one acting up,

https://www.youtube.com/watch?v=eMzaDv83eXA

Flex 6500
Smart SDR v1.11.12
Windows 10
CW skimmer using SDR bridge

Thanks
Trevor
EI2GLB
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Trevor-EI2GLB

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Posted 8 months ago

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Trevor-EI2GLB

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Kevin - KS0CW

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I assume CPU & RAM resources when you say 50%... what about GPU?
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Cal Spreitzer

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You might try assigning CPU Priority to High for both DAX and CW Skimmer programs under Task Manager Details to see if your computer will handle them smoother. 

Cal/N3CAL
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Trevor-EI2GLB

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Do you guys think it's a cpu issue?? Is there any other use for the IQ output I could use to test it,

Thanks
Trevor
EI2GLB
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Alex - DH2ID, Elmer

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That can be a latency or GPU problem. Please also post your OS.
- What graphic card are you using?
- Do you have many programs running in the background?
- Please run the DPC latency checker http://www.thesycon.de/dpclat/dpclat.exe .
- Another good program is LatencyMon
  (HE edition  isfree):  http://www.resplendence.com/latencymon
- You could also try SliceMaster by K1DBO:
   https://github.com/K1DBO/slice-master-6000/releases, which seems to create less latency.

My OS is Windows7 64bit HE on an i7 QuadCore VAIO notebook with a NVIDIA GeForce GT540M GPU. No judder and not much latency running my normal setup with 12 programs running and WSJT-X:

Latency with one slice, CWSkimmer,SDRBrige and DM780, although no judder:

Latency with 4 slices, 4xCWSkimmer, SliceMaster and DM780, no judder:

System Information with 4 slices and 4x CWSkimmer (4CPU's, 4 multithreads):

Note: GPU at 40%, CPU at 30% with 4 slices and 4x CWSkimmer open.

Alex - DH2ID
(Edited)
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K1DBO

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Trevor,

If you havent already, I'd suggest a reboot.  There are a small handful of problems that could be giving you trouble.  Most can be cleared up without a reboot, but the reboot will start you off with a clean slate.  

The question of CPU/GPU utilization is an interesting one if you are considering upgrading your system.  If not, try reducing your DAXIQ bandwidth to 48k to see if things get better.  Also, check if increasing it to 192k makes things worse.  I can usually run four DAXIQ channels into CW Skimmer at 96k without issue on my 3.6Ghz i7, but even just two running at 192k can show some sluggishness.

--Don
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Trevor-EI2GLB

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Hi Thanks for the replies, I reboot the PC daily often every few hours so that makes no difference to  the issue,

My OS is W10 just updated to latest version today,
GPU is a GT740 with 2gb
This is with most of the programs I use open and 2 slices both with a CW skimmer session connected through SDR-Bridge

There is no judder currently both Skimmers are set to 96khz setting to 192 or 48 makes no difference,

Thanks
Trevor
EI2GLB



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Tim - W4TME, Customer Experience Manager

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Run LatencyMon at the same time that you are operating DAX and after you notice the issue, then check the stats.  https://helpdesk.flexradio.com/hc/en-us/articles/202118698-Using-LatencyMon-to-collect-DPC-Latency-D...