Latency with RSPduo #rspduo (More) #rspduo


Simon Brown
 

So,

 

I’ve spent this morning revisiting the buffering for SDRplay devices and found an area where I’ve been able to greatly improve the latency but buffering the data from RSP devices (indeed most SDRs) is essential as there’s no guarantee that they reliably return data at the selected sample rate. Even a difference of 0.01% causes problems, the SDR can overrun or underrun. I notice the data rate change gently as the device warms up, once warm it’s stable.

 

Anyway, the latency is now much better, I’ve also given the priority of the SDRplay service (sdrplay_apiService.exe) a boost to high which IMO should be done as the default priority of Normal requires sharing resources with programs such as browser.

 

This priority change and the coding changes have helped, there will be a kit for the test team later today, tomorrow at the latest.

 

Simon Brown, G4ELI

https://www.sdr-radio.com

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown
Sent: 19 August 2021 06:50
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] Latency with RSPduo #rspduo

 

Hi,

 

Looking at the SDRplay support in SDR Console I see old code from the first version with 100ms buffering, the more recent SDRplay APIs (V3) have very, very low latency so I’ve just removed the need for this buffering.

 

This change will be in the next update to v3.1.

 

Simon Brown, G4ELI

https://www.sdr-radio.com

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Robin Francis
Sent: 19 August 2021 03:52
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] Latency with RSPduo #rspduo

 

Totally unscientific measurement:

SDR-duo to SDR Console 3.1 to WSJY gave average DT of 800 ms

RX-888 to SDR-console to WSJT gave average DT of 300 ms.

Console 3.1 was showing audio of 55ms

Computer time from local university SNTP server and Dimention 4.

 

Both these are more than usual . Last time I looked it I saw less than 100ms for RX-888 path and 300 for SDR-Duo path. Of course one is from USB2 port  and one from USB3.

Robin

 

Sent from Mail for Windows

 


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Larry Dodd
 

Simon,
Thank you so much. Your attention to detail and response to users requests is extraordinary. SDR Console is a fantastic program because of your efforts. You set an example to all programmers for how it should be done. Very much appreciated. Time for everyone to hit the donate box. Cheers!
Larry, K4LED 

On Aug 19, 2021, at 7:33 AM, Simon Brown <simon@...> wrote:



So,

 

I’ve spent this morning revisiting the buffering for SDRplay devices and found an area where I’ve been able to greatly improve the latency but buffering the data from RSP devices (indeed most SDRs) is essential as there’s no guarantee that they reliably return data at the selected sample rate. Even a difference of 0.01% causes problems, the SDR can overrun or underrun. I notice the data rate change gently as the device warms up, once warm it’s stable.

 

Anyway, the latency is now much better, I’ve also given the priority of the SDRplay service (sdrplay_apiService.exe) a boost to high which IMO should be done as the default priority of Normal requires sharing resources with programs such as browser.

 

This priority change and the coding changes have helped, there will be a kit for the test team later today, tomorrow at the latest.

 

Simon Brown, G4ELI

https://www.sdr-radio.com

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown
Sent: 19 August 2021 06:50
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] Latency with RSPduo #rspduo

 

Hi,

 

Looking at the SDRplay support in SDR Console I see old code from the first version with 100ms buffering, the more recent SDRplay APIs (V3) have very, very low latency so I’ve just removed the need for this buffering.

 

This change will be in the next update to v3.1.

 

Simon Brown, G4ELI

https://www.sdr-radio.com

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Robin Francis
Sent: 19 August 2021 03:52
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] Latency with RSPduo #rspduo

 

Totally unscientific measurement:

SDR-duo to SDR Console 3.1 to WSJY gave average DT of 800 ms

RX-888 to SDR-console to WSJT gave average DT of 300 ms.

Console 3.1 was showing audio of 55ms

Computer time from local university SNTP server and Dimention 4.

 

Both these are more than usual . Last time I looked it I saw less than 100ms for RX-888 path and 300 for SDR-Duo path. Of course one is from USB2 port  and one from USB3.

Robin

 

Sent from Mail for Windows

 


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Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


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Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


n6vl
 

Where do we this latest change?

de Steve N6VL


Simon Brown
 

Hi,

 

The change wasn’t needed, problem was elsewhere. New beta next week I think.

 

Simon Brown, G4ELI

https://www.sdr-radio.com

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of n6vl via groups.io
Sent: 27 August 2021 18:24
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] Latency with RSPduo #rspduo (More)

 

Where do we this latest change?

de Steve N6VL


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