I used the ini file from <a href="https://www.welle.io/devices/rawfile" rel="nofollow"

Low SNR in I/O raw file about odr-dabmod HOT 5 CLOSED

opendigitalradio commented on June 23, 2024

Low SNR in I/O raw file

from odr-dabmod.

Comments (5)

commented on June 23, 2024

Hello, It probably has something to do with welle.io expecting only unsigned 8-bit (0-255) interleaved samples, not the signed 8-bit samples generated by odr-dabmod. I'd imagine you're losing a lot of dynamic range as it is seems to be able to use the positive samples (0-127) but everything else (-1 to -128) will be out of range. That is where your SNR has gone! :-) Best regards, Rash.

…

On 4 April 2017 at 09:55, andimik ***@***.***> wrote: I used the ini file from https://www.welle.io/devices/rawfile to create an I/O raw file from an ETI. But I get a file with a very small SNR (screenshots taken from qt-dab and welle.io) [image: grafik] <https://cloud.githubusercontent.com/assets/24510556/24648669/a32cd750-1924-11e7-8cd3-836e56f3fe8d.png> [image: unbenannt] <https://cloud.githubusercontent.com/assets/24510556/24648794/14ab401a-1925-11e7-96fd-cf701441354c.png> How can I improve it? (Albert himself recommended to open an issue here) — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#13>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AIbPH5uRfWrSe-6x0tpHoCR_D8BxtYVLks5rsgWdgaJpZM4MykI8> .

from odr-dabmod.

commented on June 23, 2024

Actually, not quite... You've only lost 1-bit of resolution because the highest integer (127) can be represented with 7-bits, so you've only lost 6dB of theoretical dynamic range. I can only imagine that somehow the 'bad' negative numbers become the noise floor, leaving you with only ~6dB SNR. That's pretty close to what we can see on your qt-dab screenshot. Somebody clever will be able to elaborate on this no doubt! R.

…

On 4 April 2017 at 12:20, Rashid Mustapha ***@***.***> wrote: Hello, It probably has something to do with welle.io expecting only unsigned 8-bit (0-255) interleaved samples, not the signed 8-bit samples generated by odr-dabmod. I'd imagine you're losing a lot of dynamic range as it is seems to be able to use the positive samples (0-127) but everything else (-1 to -128) will be out of range. That is where your SNR has gone! :-) Best regards, Rash. On 4 April 2017 at 09:55, andimik ***@***.***> wrote: > I used the ini file from https://www.welle.io/devices/rawfile to create > an I/O raw file from an ETI. > > But I get a file with a very small SNR (screenshots taken from qt-dab and > welle.io) > > [image: grafik] > <https://cloud.githubusercontent.com/assets/24510556/24648669/a32cd750-1924-11e7-8cd3-836e56f3fe8d.png> > > [image: unbenannt] > <https://cloud.githubusercontent.com/assets/24510556/24648794/14ab401a-1925-11e7-96fd-cf701441354c.png> > > How can I improve it? > (Albert himself recommended to open an issue here) > > — > You are receiving this because you are subscribed to this thread. > Reply to this email directly, view it on GitHub > <#13>, or mute the > thread > <https://github.com/notifications/unsubscribe-auth/AIbPH5uRfWrSe-6x0tpHoCR_D8BxtYVLks5rsgWdgaJpZM4MykI8> > . >

from odr-dabmod.

andimik commented on June 23, 2024

Could you upload a screenshot how it should look like?

In the meanwhile I'll try to convert it with sox

from odr-dabmod.

commented on June 23, 2024

Hello, I don't have the same tools installed I'm afraid, and I don't keep IQ files around for long! The below is from RF, not baseband, and with a higher resolution (14-bit) DAC. With 8-bit samples you will see no more than the the 48 dB (8-bits*6) between the flat top and the noise floor. Expect a few dB less. Ignore the spurious spike in the picture and the uneven noise. If you wanted you could open it in a gnu radio flowgraph (not forgetting to tell it the samples are signed integers and throttle them to 2048k sampling, then pass them to an fft display. That should work but I've never had a reason to do it. R. On 4 Apr 2017 15:49, "andimik" <[email protected]> wrote: Could you upload a screenshot how it should look like? In the meanwhile I'll try to convert it with sox — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#13 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AIbPH-HFr3w9dgySVtWNCrUogqkqj5gwks5rslh3gaJpZM4MykI8> .

from odr-dabmod.

andimik commented on June 23, 2024

Yeah, your hint was the solution.

If someone else wants to try: The command is

sox -e signed-integer -r 240000 -t raw -c 2 -b 8 DabMod.iq -e unsigned-integer -t raw -c 2 -b 8 -r 240000 DabMod_new.iq
(sox has to be installed of course)

I will tell Albrecht to include this ;-)

from odr-dabmod.

Low SNR in I/O raw file about odr-dabmod HOT 5 CLOSED

Comments (5)

Related Issues (20)

Recommend Projects

React

Vue.js

Typescript

TensorFlow

Django

Laravel

D3

Recommend Topics

javascript

web

server

Machine learning

Visualization

Game

Recommend Org

Facebook

Microsoft

Google

Alibaba

D3

Tencent