diff --git a/iridium.m b/iridium.m index 5f22dab..b50c334 100644 --- a/iridium.m +++ b/iridium.m @@ -27,6 +27,9 @@ function iridium (name) [x, fs] = audioread(name); xc = (x(:,1) + i*x(:,2))'; +h_rc = fir_rrc(fs, 4/fs, 0.4, 65); +xc = filter(h_rc, 1, xc); + close all; N = length(x); @@ -38,7 +41,7 @@ xc_cfo = xc .* lo; #xc_cfo = xc_cfo .* conj(xc_cfo); phi_cfo_uw = phi_unwrap(angle(xc_cfo)); dphi_cfo = [0 diff(phi_cfo_uw)]; -foff = dphi_cfo*48000; +foff = dphi_cfo*fs; found = find_preamble(dphi_cfo) alpha_mean = 0.1; @@ -58,7 +61,7 @@ subplot(3,1,3) plot(1:N, dphi_cfo, "-o", 1:N, dphi_mean, 'r-'); legend('dphi'); grid; start=found(1) -ende=start + 128 +ende=start + 400 step=2 figure @@ -66,7 +69,7 @@ plot(real(xc_cfo(start:step:ende)), imag(xc_cfo(start:step:ende)), 'x'); grid; function found = find_preamble(phi) thr = 0.5; - nsmp = 16; + nsmp = 120; last = phi(1); count = 0; found = [];