matchingloss

Receiver filter matching loss

Since R2021a

Syntax

Lm = matchingloss(S,H)

Description

Lm = matchingloss(S,H) calculates the receiver filter loss, Lm, in dB. The receiver loss is introduced due to a mismatch between the spectrum of the received signal, S, and the frequency response of the mismatched filter, H.

Examples

Calculate Matching Loss

Compute the matching loss for a rectangular pulse and a mismatched second-order Butterworth filter.

Define sampling frequency, pulsewidth, and filter bandwidth.

Fs = 10;    % Sampling frequency (Hz)
tau = 1.2;  % Pulsewidth (s)
B = 1.0;    % Filter bandwidth (Hz)

Calculate the rectangular pulse in the time domain.

s = ones(1,Fs*tau);

Calculate the spectrum of the received pulse.

nfft = 2^(nextpow2(tau*Fs)+1);
S = fft(s,nfft);

Calculate the frequency response of a second-order Butterworth filter with bandwidth B.

[b,a] = butter(2,B/Fs);
[H,w] = freqz(b,a,nfft,'whole',Fs);

Compute the matching loss for the pulsewidth-bandwidth product, tau*B = 1.2.

Lm = matchingloss(S,H.')

Lm = 
0.9806

Input Arguments

S — Spectrum of received signal

J-by-N matrix

Spectrum of the received signal, specified as a J-by-N matrix with rows corresponding to spectra of J signals and columns corresponding to N frequency bins.

H — Frequency response of mismatch filter

K-by-N matrix

Frequency response of the mismatch filter, specified as a K-by-N matrix with rows corresponding to frequency responses of K filters and columns corresponding to N frequency bins.

Note

The columns of S and H must correspond to the same N frequency bins.

Output Arguments

Lm — Matching loss

J-by-K matrix

Matching loss, returned as a J-by-K matrix in dB. The matching loss matrix is computed for each combination of J signals and K filters.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2021a