Version 3.1 will be released on Monday, August 2nd 2021. Then it's back to user requests.

DSDplus N-FM/W-FM question

Barry WB2ZXJ
Posts: 23
Joined: Mon Aug 10, 2020 11:50 pm

DSDplus N-FM/W-FM question

#1

Unread post by Barry WB2ZXJ »

Hi Simon,

I've been playing with DSDplus and have noticed that I have to use W-FM instead of N-FM in order to decode DMR transmissions.
W-FM works (with some sync errors), N-FM never syncs.

I have a question on the horizontal bar graph showing audio levels in the Receive DSP panel. What do the two bars indicate?
One is signal, the other is? Also, switching from N-FM to W-FM causes the bars to go red (I must be over driving something).

See attached. Note: the two screenshots show idle time between transmissions.
Attachments
W-FM.jpg
N-FM.jpg

Max
Posts: 313
Joined: Thu Aug 13, 2020 9:47 am

Re: DSDplus N-FM/W-FM question

#2

Unread post by Max »

Hi Barry

See here for NFM versus WFM with DSD+:

https://www.sdr-radio.com/dsdplus

Seems is the need to have no de-emphasis or filters etc. WFM is "clean", so to speak. I believe it is similar issue in other software like SDR#:

73

Max

Barry WB2ZXJ
Posts: 23
Joined: Mon Aug 10, 2020 11:50 pm

Re: DSDplus N-FM/W-FM question

#3

Unread post by Barry WB2ZXJ »

Thanks Max,

I don't know how I missed that.

I see Simon explains that the volume widget is Red when above 95%.

https://www.sdr-radio.com/receive-dsp

Still haven't found out why there are two bars.

Barry
WB2ZXJ

Max
Posts: 313
Joined: Thu Aug 13, 2020 9:47 am

Re: DSDplus N-FM/W-FM question

#4

Unread post by Max »

No idea on that Barry, but as it's flat out red when there is wide spectrum white noise, and it does not vary according to setting of the audio level control I imagine it's some visual indication of the audio signal to noise ratio on the input to the audio chain in the presence of a signal? Just a guess though.

Hopefully Simon will illuminate us if he happens to read this post!

73

Max

Post Reply