Hi list, I am pretty new to Gnuradio / SDR, experimenting with a HackRF. As a startup experiment, I wanted to communicate with simple handheld radio devices (toy radios). These radios used DCS, and in order for my computer to bypass their squelch, I need to 1) Determine DCS-code 2) Add DCS to my transmissions
Since I didn't find any suitable tools for that (?), I have now implemented a gnuradio module to decode DCS. The source code is at bitbucket [1]. I started out by implementing the DCS decoder via a message block in python. This seemed a bit hacky, so I decided to implement it in C++ instead following the "Out-of-tree modules" tutorial [2]. In the end, I implemented it as a Stream Tag block. My thought was that it would add tags to an audio stream, and a UI component somewhere would pick up the tags and display to the user (needless to say, a DCS-squelch could be built using the tagged stream). I now have a few question, both regarding the digital signal processing in general, and regarding gnuradio. 1. Currently, my block takes digital input. Here [3] you can see a picture of how I go from 960 hz sampled audio stream via DC-blocker, thresholding , interpolation and decimation into a digital signal (to the 'old' message sink). In the next stage, I'd like to take an audio source (with a few selectable common audion samplerates) instead, which means that my block must do all those things within the block itself. How is this normally done? Do I create a hierarchical block containing these blocks "under the hood", plus my new digital-in-DCS-decode block? 2. Does it make sense to have DCS as a tagged stream? Should I chose some other type to communicate DCS ? 3. Are there better ways to extract the digital signal from the audio source than my schematic above? Am I doing something stupid? 4. Are there any suitable UI-components I can use to display DCS information - e.g. something which show information from streamed tags , or mechanisms to modify variables based on tag info? Grateful for suggestions and ideas. Martin Holst Swende [1] https://bitbucket.org/holiman/gnuradio-dcs [2] http://gnuradio.org/redmine/projects/gnuradio/wiki/OutOfTreeModules [3] http://martin.swende.se/graph_part.png _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
