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JvanKatwijk / qt-dab

Qt-DAB, a general software DAB (DAB+) decoder with a (slight) focus on showing the signal
http://www.sdr-j.tk
GNU General Public License v2.0
300 stars 62 forks source link

RX-888 #245

Closed jjcarron closed 1 month ago

jjcarron commented 2 years ago

Trying to start the application with ExtIO_sddc.dll for RX-888 issues an error message "cannot handle this rate"

Any solution to solve it?

JvanKatwijk commented 2 years ago

I do not know the RX-888, what is the rate?

Op za 27 nov. 2021 om 17:12 schreef jjcarron @.***>:

Trying to start the application with ExtIO_sddc.dll for RX-888 issues an error message "cannot handle this rate"

Any solution to solve it?

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-- Jan van Katwijk

jjcarron commented 2 years ago

It is a relatively new 16-bit SDR.

image

I have got the following error.

error

Sampling

JvanKatwijk commented 2 years ago

Sampling frequency seems a little too high, if I read it correctly, it is 64000000, while DAB needs something in the range of 2 MHz (2.048 MHz to be precise, but from 2 .. app 4 or 5 MHz we can resample) Cant you change the sampling frequency?

Op za 27 nov. 2021 om 19:49 schreef jjcarron @.***>:

It is a relatively new 16-bit SDR.

[image: image] https://user-images.githubusercontent.com/28822636/143718645-861e429f-59b0-4626-b43e-c720bca290b5.png

I have got the following error.

[image: error] https://user-images.githubusercontent.com/28822636/143718595-329f76c1-d8ab-4967-ac6f-3af4389cf539.PNG

[image: Sampling] https://user-images.githubusercontent.com/28822636/143718593-eb91631e-451c-432c-b8b5-355a6f2d174a.PNG

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-- Jan van Katwijk

jjcarron commented 2 years ago

The lowest accepted is 50MHz When I try to apply a lower value. It set to 50MHz when I press apply

JvanKatwijk commented 2 years ago

Interesting device, do you have a description of the library functions?

50Mhz would (almost) cover the whole DAB band (175 .. 240 MHz), so in order for the data to be useful you need some filtering. If there is some filtering on say the center 2 or 3 MHz, then it is just a matter of decimating the samplerate to something that is better manageable, if there is no filtering then a software filtering/decimation would be needed, starting at 64 MHz, and a 32 times decimation results in 2 MHz, that is easy to upsample to 2.048 MHz

Op za 27 nov. 2021 om 20:28 schreef jjcarron @.***>:

The lowest accepted is 50MHz When I try to apply a lower value. It set to 50MHz when I press apply

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-- Jan van Katwijk

jjcarron commented 2 years ago

The github for the driver is :

jjcarron commented 2 years ago

https://github.com/ik1xpv/ExtIO_sddc?spm=a2g0o.detail.1000023.1.3f982f06dfes3S

I am just starting with SDR and not sure to understand. WHen you say A software filtering is needed, you mean I shoud write a fonction in the driver to divide the actual sampling rate as I have no direct acces to the device itself, don't you?

jjcarron commented 2 years ago

Config.cpp specify :

include "license.txt"

include "config.h"

bool saveADCsamplesflag = false; uint32_t adcnominalfreq = DEFAULT_ADC_FREQ; uint32_t MIN_ADC_FREQ = 50000000; // ADC sampling frequency minimum uint32_t MAX_ADC_FREQ = 140000000; // ADC sampling frequency minimum uint32_t N2_BANDSWITCH = 80000000; // threshold 5 or 6 SR bandwidths

JvanKatwijk commented 2 years ago

Well, first of all I try to understand what the features/capabilities of the device are. Most devices I have seen so far have options to set the samplerate to a few MHz, some - not all - have the possibility of filtering

Just thinking loud, if you start with a samplerate of 64 MHz, then decimating 32 times is doable, though it would be easier to address (for me) if I knew whether or not to take filtering into account

If filtering is not provides by the device and you tune to say, a DAB channel on 205 MHz, then you basically tune to the whole band (205 - 32 to 205 + 32) and you get data from all channels in the band, something you really do not want

Filtering as such is not too complex, especially half band filtering, but both 32 times decimating and filtering is now not implremented in the extio handler and - suppose I will be able to do that - I need that information

Op za 27 nov. 2021 om 21:12 schreef jjcarron @.***>:

https://github.com/ik1xpv/ExtIO_sddc?spm=a2g0o.detail.1000023.1.3f982f06dfes3S

I am just starting with SDR and not sure to understand. WHen you say A software filtering is needed, you mean I shoud write a fonction in the driver to divide the actual sampling rate as I have no direct acces to the device itself, don't you?

— You are receiving this because you commented. Reply to this email directly, view it on GitHub https://github.com/JvanKatwijk/qt-dab/issues/245#issuecomment-980794708, or unsubscribe https://github.com/notifications/unsubscribe-auth/ACCPHQHXMIJZZFOO3NKVJRLUOE3R7ANCNFSM5I4KUGTA . Triage notifications on the go with GitHub Mobile for iOS https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675 or Android https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub.

-- Jan van Katwijk