Continuous playback

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cdekker
Posts: 33
Joined: Fri Oct 30, 2015 3:33 pm

Re: Continuous playback

Post by cdekker » Thu Dec 17, 2015 3:12 pm

Pavel,

We want to play a large recorded file of "1 Msps samples" via a RedPitaya board where the 125 MHz oscillator is 'replaced' with an accurate 32 MHz clock from a Rubidium oscillator (also used for recordings).

Will it be sufficient to change the command line " ./dac-player 125 record.dat" into " ./dac-player 32 record.dat " to get am equivalent 1 Msps analog output? Or should we make additional preparations?

Best regards, Cees Dekker

pavel
Posts: 632
Joined: Sat May 23, 2015 5:22 pm

Re: Continuous playback

Post by pavel » Thu Dec 17, 2015 3:26 pm

Hi Cees,

Yes, './dac-player 32 record.dat' should work in this case.

Best regards,

Pavel

cdekker
Posts: 33
Joined: Fri Oct 30, 2015 3:33 pm

Re: Continuous playback

Post by cdekker » Wed Dec 23, 2015 6:02 pm

-deleted- probably misinformation, sorry for the inconvenience, if any.
Last edited by cdekker on Thu Dec 24, 2015 9:42 am, edited 2 times in total.

hermy_sf
Posts: 9
Joined: Sun Mar 28, 2021 8:04 am

Re: Continuous playback

Post by hermy_sf » Sun Mar 28, 2021 8:22 am

Hi Pavel,

Is there any newer version of the playback software for the RP ? I am interested in directly playing back 14 bit data recorded with 3.472 MS/s at original speed (recorded using the rpsa_client).

I tried to download dac_player.bit , but the link
https://googledrive.com/host/0B-t5klOOy ... player.bit
posted by you on Nov 19th 2015 doesn't work any more, at least not on my computer. Is there a more recent source for the dac_player.bit ?

Best regards

Hermann

pavel
Posts: 632
Joined: Sat May 23, 2015 5:22 pm

Re: Continuous playback

Post by pavel » Sun Mar 28, 2021 10:12 am

Here is a link to a more recent version:
https://www.dropbox.com/sh/5fy49wae6xwx ... r.zip?dl=1

I don't know if it works at 3.472 MSPS.

hermy_sf
Posts: 9
Joined: Sun Mar 28, 2021 8:04 am

Re: Continuous playback

Post by hermy_sf » Wed Apr 07, 2021 6:44 am

Hi Pavel,

Sorry for not answering earlier, I was quite busy in the last days. I just want to report that your code for DAC-player perfectly works at different sampling rates. I tried up to 7MS/s. The background of my project is that I have recorded in the past complete spectral bands from medium wave radio (500 - 1600 kHz) on videorecorder tapes which now I want to digitize. Besides I would like to record current medium wave bands for historical reasons as long as there are still broadcasting stations in this frequency range before they definitely quit their services. The nice thing with my recordings is that you can now directly connect a radio receiver at the Red Pitaya DAC output, play the data file and the tune through the whole frequency band, listening to all playing radio stations you want just by turning the tuning knob. Before I could do that only with the analog VCRs which have quite lousy SNR. The RP in contrast provides perfect signal quality.
With your code I have now realized an old dream of mine: I can preserve this piece of broadcasting history in a digital repository.

Many thanks for the code and your help !

The only problem I still have is that I made the recordings with the pre-installed streaming app which terminated the recording after reaching 4GB of file size. Is there a version which avoids this limitation ? I need to record up to 100GB per file. I have not yet tried the adc-recorder.c code because I could no yet compile it correctly, but would that one help ?

Best regards
Hermann

pavel
Posts: 632
Joined: Sat May 23, 2015 5:22 pm

Re: Continuous playback

Post by pavel » Wed Apr 07, 2021 12:29 pm

Hi Hermann,

Thank you for testing the DAC player application and for the detailed description of your project. Very interesting.

Have you looked at the SDR transceiver or wideband SDR transceiver applications? I think they're more suitable for recording of the 500-1600 kHz frequency range. With these applications, GNU radio can be used to record and playback the data. It's also possible to write a small C or Python program that would receive the data from these applications via a network connection and write the data to a file. In this case, creating a 100 GB file shouldn't be a problem if your file system supports large files. If you are interested, I can help you with the writing of the C or Python programs.

Best regards,

Pavel

hermy_sf
Posts: 9
Joined: Sun Mar 28, 2021 8:04 am

Re: Continuous playback

Post by hermy_sf » Sat Apr 10, 2021 9:30 pm

Dear Pavel,
Many thanks for the hint - I just tried to install the wideband transceiver according to the installation guide in the link given by you ,i.e. 'http://pavel-demin.github.io/red-pitaya ... iver-wide/'. I copied the SD-card-image files to the root directory of the same SD-card where the RP ecosystem is installed. When executing the command 'sudo apt-get install gnuradio python-numpy python-gtk2' the procedure runs until it tries to access http://ports.ubuntu.com. Then a lot of errors occur e.g.:

Err:1 http://ports.ubuntu.com/ubuntu-ports xenial-updates/main armhf libdrm2 armhf 2.4.76-1~ubuntu16.04.1 404 Not Found [IP: 91.189.88.152 80]

Obviously the destination site 'http://ports.ubuntu.com/ubuntu-ports xenial-updates/main' could not be found, and in fact I cannot localize it neither with my webbrowser.

What am I doing wrong ?

Best regards
Hermann

pavel
Posts: 632
Joined: Sat May 23, 2015 5:22 pm

Re: Continuous playback

Post by pavel » Sun Apr 11, 2021 10:11 am

The red-pitaya-alpine-3.12-armv7-20210326.zip file should be unpacked to an empty FAT32-formatted micro SD card. For example, a freshly unpacked factory formatted micro SD card would most likely be OK.

GNU Radio should be installed on a computer that will be used for recording.

However, GNU Radio isn't strictly necessary. Here is a link to a Python script that can be used for recording:
https://github.com/pavel-demin/red-pita ... mote_rx.py

hermy_sf
Posts: 9
Joined: Sun Mar 28, 2021 8:04 am

Re: Continuous playback

Post by hermy_sf » Wed Apr 14, 2021 9:04 am

Hi Pavel,
Sorry for acting 'unskilled', I am not very familiar with these issues and I am running a Windos-PC for communication with the RP. In your installation guide (http://pavel-demin.github.io/red-pitaya ... iver-wide/) you write how to install GNURadio unter LINUX which seems quite straightforward.
Under Windows there are several distributions of GNURadio, I tried the Geof Nieboer's installer hosted at gcndevelopment.com, but according to their installation guide I have then to configure the system for either a RTLSDR or a USRP. I guess that the RP SDR is none of the two, so I am a bit stuck here. Have you tried GNURadio under Windows and/ or would you recommend another Distribution ?
Best regards
Hermann

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