run /users/swinkels/deploy/MatlabVirgoTools/trunk/startup.m

g = utc2gps(2018,4,6,8,10,0);

dur = 10*60;

phi_chan = 'DAQ_LNFS_6MHz_phi';
freq_chan = 'INJ_LNFS_FREQ1';

freq_nom = 6270777;


[phi, t] = getChannel(phi_chan, g, dur);
[freq, tt] = getChannel(freq_chan, g, dur);


%%

dt = t(2) - t(1);

dphi_wrap = diff(phi);
dphi_wrap = [dphi_wrap(1); dphi_wrap]; % add extra sample for plotting
dphi = dphi_wrap - 2*pi*round(dphi_wrap / (2*pi));
freq_meas = -dphi / (dt * 2 * pi);

%%
plot(t, phi)
%%
plot(t, dphi_wrap)
%%
plot(t, dphi)

%%

n = 1000;

plot(t, freq_meas, ... %    t(1:n:end), blockaver(freq_meas, n), ...
    tt, freq - freq_nom); 
ylim([min(freq_meas)-1, max(freq_meas)+1])
xlabel(sprintf('Time (s) after %s', gps2str(g)))
ylabel(sprintf('Frequency deviation (Hz)'))
legend({sprintf('measured frequency using diff(%s)', phi_chan),...
    sprintf('%s - %i', freq_chan, freq_nom)}, 'interpreter', 'none')