Perhaps it is just PER that I should minimize on? I can't conceive of a case where your BER would go up but your PER would stay the same ...
On Wed, Aug 4, 2021 at 8:16 AM Tim Meehan <btmee...@gmail.com> wrote: > Hi Al - nice to hear from you. > > I'm trying to learn ARM cross compiling, but it would be nice to also have > some folks to check on live hardware. The only SDR I have is receive-only > (NooElec NESDR Nano2+, and your web link is NEAT!). > > In the script snippet that I attached, there was a bit at the end that I > thought might have been the "figure of merit" ... if so ... I can try and > tune the knot placement based on these numbers. > > Uncoded PSK Eb/No simulation: > No = 1.00 dB (1.26 linear) > Eb = 0.00 dB (1.00 linear) > Eb/No = -1.00 dB (0.79 linear) > Using: HRA_112_112 > Using: HRA_112_112 > Nframes: 100 > CodeLength: 224 offset: 0 > written: 22400 > .....xxx.x.x.x...xmeasured double sided (real) noise power: 0.629226 > xx.x............................................x....x....x....x..x.........x....xtotal > iters 5469 > Raw Tbits: 22400 Terr: 2268 BER: 0.101 > Coded Tbits: 11200 Terr: 68 *BER: 0.006* > Tpkts: 100 Tper: 17 *PER: 0.170* > > I gather that having both of these numbers small is good? Minimizing on > two numbers is a bit challenging, I might just try to minimize based on > sqrt(BER^2 + PER^2) ... any thoughts would be appreciated. > > On Wed, Aug 4, 2021 at 3:32 AM Al Beard <bear...@unixservice.com.au> > wrote: > >> *Hello Tim,* >> >> *It's great to have you onboard. I'm more of an "implimenter", by no >> means good at C or C++.* >> *So I can't help to that depth.* >> >> *I can compile code on ARM and Intel Linux platforms here and with >> transceivers, give it a go.* >> >> *So, if I can be useful.* >> >> *My SDR here in western Sydney, Australia can do Codec2 decode though >> currently in one mode.* >> *(easily changeable in a script file) Web browse 110.143.195.8:8073 >> <http://110.143.195.8:8073>* >> >> *You may notice the M17 project has chosen the Codec2 modes 1600 and 3200 >> to "replace" AMBE* >> *in an open source transceiver project. * >> >> *Welcome* >> >> >> *Alan VK2ZIW * >> >> *On Tue, 3 Aug 2021 17:14:15 -0500, Tim Meehan wrote* >> > Hi - I'm not extremely versed in digital modes, but I am well versed in >> optimization. I think that HAM radio should be something open source, which >> is why Codec2 appeals to me. >> > >> > Before I post a large blob of C code, I wanted to mention that I have a >> program that I have written a genetic optimizer to move spline knots around >> - and I'd be happy to run the optimizer based on BER/PER ... however ... I >> need someone to explain to me how I might generate quantities to optimize >> on. I don't need bunches of help, just enough so that I can write it >> myself. >> > >> > I found that the 16-sample clamped endpoint spline with log-spaced >> samples worked the best, so I'll chop out the higher sample density parts >> of the code. My hope was faster AND more accurate, but I think all I got >> was faster and LESS accurate. Perhaps wiser eyes than mine can help me out. >> > >> > The test script that I was using was: >> > #!/bin/sh >> > ./ldpc_enc /dev/zero - --sd --code HRA_112_112 --testframes 100 \ | >> ./ldpc_noise - - 1 \ >> > | ./ldpc_dec - /dev/null --code HRA_112_112 --sd --testframes >> > >> > The code is (simply replace phi0.c with this):// phi0.c >> > #include <stdint.h> >> > #include <stddef.h> >> > >> > float coeffs_clamped_16[16] = { >> > 7.93223341e+07, 1.55433768e+07, 3.60871810e+06, 7.33752374e+05, >> > 1.65434845e+05, 3.44055511e+04, 7.62050634e+03, 1.60695364e+03, >> > 3.52218272e+02, 7.50245180e+01, 1.64584579e+01, 3.63755151e+00, >> > 8.75888035e-01, 1.72673513e-01, 6.76273536e-03, -7.75296180e-03}; >> > >> > float x_16[16] = { >> > 1.00000000e-04, 2.15443469e-04, 4.64158883e-04, 1.00000000e-03, >> > 2.15443469e-03, 4.64158883e-03, 1.00000000e-02, 2.15443469e-02, >> > 4.64158883e-02, 1.00000000e-01, 2.15443469e-01, 4.64158883e-01, >> > 1.00000000e+00, 2.15443469e+00, 4.64158883e+00, 1.00000000e+01}; >> > >> > float y_16[16] = { >> > 9.90348755e+00, 9.13595919e+00, 8.36843084e+00, 7.60090254e+00, >> > 6.83337448e+00, 6.06584753e+00, 5.29832570e+00, 4.53082768e+00, >> > 3.76344015e+00, 2.99656512e+00, 2.23206146e+00, 1.47840690e+00, >> > 7.71936833e-01, 2.32985688e-01, 1.92853284e-02, 9.07998596e-05}; >> > >> > static size_t >> > bisect(float x, float *restrict x_data, size_t size) >> > { >> > size_t left = 0; >> > size_t right = size - 1; >> > int max_iterations = 32; /* waay higher than we need */ >> > >> > while (right - left > 1 && max_iterations--) { >> > size_t middle = left + (right - left)/2; >> > float xm = x_data[middle]; >> > if (x < xm) >> > right = middle; >> > else if (xm < x) >> > left = middle; >> > } >> > >> > return left; >> > } >> > >> > static float >> > spline_interpolate(float x, >> > float *restrict x_data, >> > float *restrict y_data, >> > float *restrict M, >> > size_t size) { >> > size_t i = bisect(x, x_data, size); >> > float h = x_data[i + 1] - x_data[i]; >> > float z = (x - x_data[i])/h; >> > float h2 = h * h; >> > >> > float c1 = (M[i + 1] - M[i]) * h2 / 6.0; >> > float c2 = M[i] * h2 / 2.0; >> > float c3 = y_data[i + 1] - y_data[i] - (M[i + 1] + 2.0 * M[i]) * h2 >> / 6.0; >> > >> > return ((c1 * z + c2) * z + c3) * z + y_data[i]; >> > } >> > >> > extern float >> > phi0(float x) { >> > if (x <= x_16[0]) >> > return 10.0f; >> > if (x >= x_16[15]) >> > return 0.0f; >> > >> > return spline_interpolate(x, x_16, y_16, coeffs_clamped_16, 16); >> > } >> >> >> --------------------------------------------------- >> Alan VK2ZIW >> Before the Big Bang, God, Sela. >> OpenWebMail 2.53, nothing in the cloud. >> >> _______________________________________________ >> Freetel-codec2 mailing list >> Freetel-codec2@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 >> >
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