Hi list! I think this project is really interesting, and I am writing bits of software for experimenting with HF / DSP stuff. The software I am writing may even be useful for this project.
I have thoughts along the lines that the code I have written can easily be expanded to become a PC software modem for codec2 over HF. My next steps would in fact be to write BPSK modulator / demodulators supporting multiple carriers OFDM style. But I have little idea if this fits into the overall design goals of the project. I have a number of questions about this. First and foremost if similar software already exists in a usable form? Secondly what level of error correction is envisioned for the link layer ? I am thinking that little or no FEC should be at the link layer. The link layer should only have a robust packet delimiting mechanism, and furthermore report "soft bits" to the decoder so that trellis / viterbi demodulation may be done in conjunction with higher level protocol for FEC / bit diffusion etc. But I am open for any suggestion. About the bits I have written so far, with the intention on releasing on a GNU license: The software was written to be toolbox /playground for testing various ham related DSP stuff, and doesn't perform any real useful functions. Currently it does some dynamically adaptive equalization of SSB voice through D20 wavelet decomposition - composition, but it hasn't gotten to the point where it is useful. The software is written for Windows, even though Linux is my favoured development platform. But I realize that Windows has the majority of users, hence this choice. Still it should be easy to "port" to Linux as the code is fairly platform independent. Only the Audio I/O would have to be rewritten. Some features: * C++ object oriented * No GUI at the moment. * Audio capture from wav device ( "low" latency ) * Audio playback to wav device ( "low" latency ) * Pluggable stream objects used to create signal paths * Low pass filters * upsampling / downsamplnig (not efficient as rational resampler) * File IO * Wavelet decomposition / composition classes (D4 and D20) * links to hamdsp for PTT control * All samples are represented as 32 bits float Comments ? Questions ? 73 de LA9OSA / Frank ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
