Re: Thumb dv audio breakup

"John D. Hays" <john@...>

I don't have a definitive answer, but in VOIP applications, 36ms of Jitter is considered high.

"Jitter - This is measured in milliseconds and is created by some instability in your connection. It is a fluctuation in the signal such that it becomes out of sync or displaced from where it should be in the transmission. It is effectively a continuous variation in the delay of packet delivery. VoIP jitter can be tolerated up to 20ms to 30 ms." --

Some applications in the VOIP telephony world implement a 'jitter buffer' to try to smooth jitter out a bit (at the cost of added delay).

Unfortunately, the best thing is to try to find a way (through your ISP?) to reduce the jitter number.

On Tue, Jan 5, 2016 at 10:12 AM, Les Norton gm4jnw@... [UniversalDigitalRadio] <UniversalDigitalRadio@...> wrote:

Just done a test as suggested:

Packet loss 0%
Ping 221ms
Jitter 36ms

What do you think?

On 5 Jan 2016, at 18:05, 'John D. Hays' john@... [UniversalDigitalRadio] <UniversalDigitalRadio@...> wrote:

A tool everyone should get familiar with

Packet loss and jitter are your enemies.  These are things that can only be fixed on your network connection / ISP.

The connection between the computer and the ThumbDV or PiDV is simply a serial port that passes packets back and forth.  PCM (Audio) to AMBE or AMBE to PCM (Audio), everything else is up to the application (which in turn uses services from the operating system).

On Tue, Jan 5, 2016 at 9:33 AM, Les Norton gm4jnw@... [UniversalDigitalRadio] <UniversalDigitalRadio@...> wrote:

I did some tests and here are the details:

here are 3 tests i did:

1) transmit 8 seconds, return  6.8 seconds
2) transmit 11.3 secs return 7.8 seconds
3) transmit 15.1 secs return 11.1 seconds

So you can see the reason for the dropped words on transmission

Also restarted the router in case it was an internet issue.
Have pretty slow internet speed 2.2mbps but it never caused issues with my previous dongle.

I agree could be packet loss - have also shared the info with the retailer

Or is it a matter of returning it?


John D. Hays

PO Box 1223, Edmonds, WA 98020-1223 


John D. Hays

PO Box 1223, Edmonds, WA 98020-1223 

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