CDL Channel always outputs zeros

Hello,

I'm trying to use CDL Channel model but it always outputing zeros regardless of the signal input, and if it is custom mode or CDL-E. The problem should be very basic, but I don't know how these channel models work. The sample rate is 1728000 and the output size is 72 x 4. Below is part of the CDL-E code:

fc = 1.9e9;
% 4-elements ULA
RX_antenna = phased.IsotropicAntennaElement('FrequencyRange',[1e8 2e8]);
RX_array = phased.ULA('Element',RX_antenna,'NumElements',num_antennas, 'ElementSpacing',d);

cdl = nrCDLChannel(...
    "DelayProfile","CDL-E",...
    "CarrierFrequency",fc,...
    "MaximumDopplerShift",0,...
    "ReceiveAntennaArray",RX_array,...
    "SampleRate",Fs,...
    'ReceiveArrayOrientation', [30; 0; 0]);

% Transmitter composed of 1 antenna
cdl.TransmitAntennaArray.Size = [1 1 1 1 1];

Answer 1

[Rangesh]

Hi Tiago,

I understand that you are want to know about the presence of zeros in the output signal and the reason behind it. The zeros in the output signal occur because the operating or carrier frequency falls outside the specified operating frequency range of the antenna element.

In this case, when the frequency is outside the range of “1e8 to 2e8”, the antenna element does not respond, resulting in zero values in the output signal.

To obtain a non-zero response, it is necessary to adjust the operating frequency within the given range. By setting the operating frequency within the specified range, the antenna element will exhibit a response other than zero.

For more understanding on "phased.IsotropicAntennaElement" and its functionality, Kindly refer this documentation: https://www.mathworks.com/help/phased/ref/phased.isotropicantennaelement-system-object.html.

I hope this resolves your query.

Thanks,

Rangesh.