Applying a phase shift to a complex signal vector

Hello!

I am trying to apply a phase shift to a complex signal vector for a small projecct and can't quite figure out how to do it: heres my current code:

%Form Complex matrices

x1 = complex(x1_Re, x1_Im);

x1=double(x1);

x0 = complex(x0_Re, x0_Im);

x0 = double(x0);

%Unshift the signals

Shift_tile0 = deg2rad(-151.093);

unshifted_signal0 = x0 .* exp(-1i * Shift_tile0);

Shift_tile1 = deg2rad(-86.0178);

unshifted_signal1 = x1 .* exp(-1i * Shift_tile1);

I am on MATLAB 2022b, and the sampling frequencies for x1,x0 are known. I am building x1 and x0 from the I and Q data received.

Answer 1

[William Rose]

@Maxime Zelenko.

[Edit: In case it is not obvious, x is the original signal, and y is the phase-shifted signal.]

Since you are working with I-Q signals, make an I and Q signal that are 90 degrees apart, since this is what In-phase and Quadrature mean. In the example below, a phase shift of -60 degrees is applied.

dt=1e-2; t=(0:99)*dt;  % time vec tor (s) 
T=0.2; % period (s)
x=cos(2*pi*t/T)+1i*sin(2*pi*t/T);
% Apply phase shift
phi=-pi/3;
y=x*exp(1i*phi);
% Plot results
figure
plot(t,real(x),'-r',t,imag(x),'-b',t,real(y),'--r',t,imag(y),'--b');
legend('x_{Real}','x_{Imag}','y_{Real}','y_{Imag}'); 
xlabel('Time (s)'); ylabel('Amplitude')

Looks reasonable. Good luck.