Complex operation of the real valued signal in MATLAB SIMULATION

I want to multiply j (complex operator) to a real valued sine signal of certain frequency in matlab simulation which I am unable to do in Simulink .

{For eg: when we multiply

j*A*sin(wt +phi) where w= 2*pi*f, f= unknown frequency, phi= unknown phase angle and A = unknown magnitude, the result comes out to be

= A*cos(wt +phi) }

[Alan Stevens]

Can't you simply add an extra pi/2 to phi in Simulink to achieve the same resut?

[MANAS MISHRA]

Thanks for the response .

Now i cant add pi/2 simply because the real valued signal contains many sine signals of different frequencies such as

sin(w1*t)+sin(w2*t)+sin(w3*t)+........

Moreover I even can't differentiate or integrate the signal as as the frequencies of these signals are unknown hence I cannot obtain the pi/2 phase shifted version of the above real valued signal. So I am left only with the j operater to do my job.

Answer 1

[David Goodmanson]

Well,

j*A*sin(wt+phi)   does not equal   A*cos(wt+phi) 

although

  Re[    exp(j*(wt+phi)) ] = cos(wt+phi)

and

j*Re[ -j*exp(j*(wt+phi)) ] = j*sin(wt+phi)   % two introduced factors of j on left hand side

[MANAS MISHRA]

Thank you Mr. David for enlightening me.

Stay Safe and Stay Blessed.