Hello Hussein,
I understand you are trying to modulate the phase of LFM signal using Kasami sequence for PC-FMCW radar.
To modulate the phase of a LFM signal using kasami sequence, you can use the following steps:
- Generate a Kasami sequence using the "comm.KasamiSequence" function, as you have already done in the code you provided.
- Create a vector to store the modulated LFM signal and generate an LFM signal using "phased.LinearFMWaveform" function.
- For each bit in the Kasami sequence, if the bit is 1, add a random phase shift to the LFM signal's phase. If the bit is 0, do not apply a phase shift.
- Store the modulated LFM signal in the vector created in step 2. Repeat steps 5-6 for each bit in the Kasami sequence until the end of the sequence. Plot the modulated LFM signal to visualize the phase modulation.
Here is a sample code for better understanding,
% Generate a Kasami sequence
waveform = phased.LinearFMWaveform('PulseWidth',100e-6,...
'SweepBandwidth',200e3,'PRF',4e3);
kasamiSeq = comm.KasamiSequence('Polynomial',[6 1 0], 'InitialConditions',[0 0 0 0 0 0 0 1],'SamplesPerFrame',512);
% Create a vector to store the modulated signal
modLFM = zeros(length(waveform()),1);
% Generate an LFM signal
LFM = waveform();
% Set the phase of the LFM signal to 0
LFM_phase = zeros(length(LFM),1);
% Iterate over each bit in the Kasami sequence
for i = 1:length(kasamiSeq)
% If the bit is 1, add a random phase shift to the LFM signal's phase
if kasamiSeq.InitialConditions(i) == 0
phase_shift = rand*2*pi; % Generate a random phase shift between 0 and 2*pi
LFM_phase = LFM_phase + phase_shift; % Add the phase shift to the LFM signal's phase
end
% Combine the new phase with the original LFM signal's magnitude
modLFM = modLFM + LFM.*exp(1j*LFM_phase);
end
For further information, kindly refer the following documentation:
