New gnuradio repository for the AMBE3000 devices


 

I have a new gnuradio OOT (out-of-tree) repository, gr-ThumbDV, at http://github.com/ac2ie.

This repository will build two blocks for encoding and decoding audio data. It can use either the AMBE-3000 DStar vocoder or the DMR vocoder. Additional AMBE-3000 vocoder methods can be easily added. The AMBE-3000 has dozens of available methods.

These are very basic blocks. No additional info is encoded or decoded. The encoded data will be about 35 times smaller than the original audio data. Each 160 16-bit audio samples is converted to 9 bytes, and vis-versa.

By themselves, these blocks are not suitable for building a DMR or DStar transmitter or receiver. My intention is to build additional blocks in this repository that will, when combined with these blocks, allow you to construct a DMR or DStar receiver or transmitter. While my other repository, gr-ambe3000, is more monolithic and for DStar only, this new repository will be more modular and flexible.


 

Okay, it really wasn't that difficult to design a "bare-bones" DStar transmitter with the addition of a few standard gnuradio blocks. By "bare-bones", I mean no DStar header, slow-data or termination flag. A commercial receiver might complain a bit, but it will receive and decode the audio just fine. A flow-graph for this simple transmitter is now included.


 

I have added a couple of new blocks to the gr-ThumbDV OOT so that a more-or-less complete DStar receiver can be built. See the included image. I'm now thinking about what I need for DMR rf flow-graphs...

I guess these blocks should work with the PiDV as well. Somebody will have to let me know...