Phased Array Toolbox: Problem with Free space channel in implementing FSK radar. Phase shift depends only on carrier frequency and not on the base band signal

I'm trying to implement FSK radar using phase array toolbox (please refer to the code snippet attached) and have a problem with free space channel, as it gives same phase shift for both the signal tones with different frequencies. one workaround I found is to send each signal thru different channels with corresponding frequency shift between the carrier frequencies. Is there any better way of doing it?

[Monikka Busto]

How did you obtain the correct phase shift?

Answer 1

[Honglei Chen]

The FreeSpace channel assumes all signals are at the same frequency, or at least can be considered as in the same frequency. In your FSK system, if it's important to get the phase shift corresponding to the given frequency, you may want to try WidebandFreeSpace channel so the signal is automatically divided into subbands and the phase shifts are computed for each subband. However, because the number of subbands is finite, your frequencies may not fall exactly on a subband frequency so some approximation may occur. I'll be interested to know if this workaround addresses your issue.

HTH