46 lines
1.3 KiB
Matlab
46 lines
1.3 KiB
Matlab
% fsk_lib_ldpc.m
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%
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% Library of common functions used for LDPC coded 4FSK modem experiments
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fsk_lib;
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ldpc;
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% set up modem waveform, real signal that an pass through a SSB radio
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function [states M] = modem_init(Rs,Fs,df)
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M = 4;
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if Rs == 100 P=8; end
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if Rs == 400 P=10; end;
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states = fsk_init(Fs,Rs,M,P=10,nsym=100);
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states.tx_real = 1;
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states.tx_tone_separation = Rs;
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if Rs == 100
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states.ftx = 1500 -2.5*states.tx_tone_separation + states.tx_tone_separation*(1:M);
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elseif Rs == 400
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states.ftx = 600 + states.tx_tone_separation*(0:M-1);
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else
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disp("unknown symbol rate");
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end
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states.fest_fmin = 500;
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states.fest_fmax = 2500;
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states.fest_min_spacing = Rs/2;
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states.df = df;
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states.ber_valid_thresh = 0.1;
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states.ber_invalid_thresh = 0.2;
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states.amp_scale = 1000;
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end
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% set up modem waveform and LPC code
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function [states code_param] = fsk_lib_ldpc_init (HRA, Rs, Fs, df=0, plots=0)
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[states M] = modem_init(Rs, Fs, df);
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N = states.N;
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if plots; states.verbose = 0x4; end
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Hsize=size(HRA);
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states.rate = (Hsize(2)-Hsize(1))/Hsize(2);
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code_param = ldpc_init_user(HRA, modulation='FSK', mod_order=states.M, mapping='gray');
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states.coden = code_param.coded_bits_per_frame;
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states.codek = code_param.data_bits_per_frame;
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end
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