rectpulse

Rectangular pulse shaping

Syntax

Y = rectpulse(X,nsamp)

Description

Y = rectpulse(X,nsamp) performs rectangular pulse shaping on X and returns Y, increasing the sample rate of X by repeating each sample nsamp times.

Examples

Increase Sample Rates

Create an array of modulated symbols. The first channel (column) contains QPSK-modulated symbols. The second channel contains 16QAM-modulated symbols.

M_psk = 4;   % PSK modulation order
M_qam = 16;  % QAM modulation order
nsymb = 10;  % Number of modulated symbols

ch1 = pskmod(randi([0 M_psk - 1],nsymb,1),M_psk,pi/4);
ch2 = qammod(randi([0 M_qam - 1],nsymb,1),M_qam);
X = [ch1 ch2];

Plot the real and imaginary parts of the modulated symbols.

figure
subplot(2,1,1)
stem(real(X))
grid on
xlabel('Symbols')
ylabel('\Re(X)')
subplot(2,1,2)
stem(imag(X))
grid on
xlabel('Symbols')
ylabel('\Im(X)')

Set the number of samples per symbol.

nsamp = 4;

Perform rectangular pulse shaping and display the result.

Y = rectpulse(X,nsamp);
figure
subplot(2,1,1)
plot(real(Y),'-') 
grid on
xlabel('Samples')
ylabel('\Re(y)')
ylim([-3.5 3.5])
subplot(2,1,2)
plot(imag(Y),'-')
grid on
xlabel('Samples')
ylabel('\Im(Y)')
ylim([-3.5 3.5])

Input Arguments

X — Input symbols

vector | matrix

Input symbols, specified as a vector or matrix. If X is a matrix with multiple rows, the function treats the columns as independent channels.

Data Types: double | single
Complex Number Support: Yes

nsamp — Number of samples per symbol

positive integer

Number of samples per symbol, specified as a positive integer.

Data Types: double | single

Output Arguments

Y — Output samples

vector | matrix

Output samples, returned as a vector or matrix.

• If the input X is a vector, the output is an L-element vector consisting of each sample in X repeated nsamp times, where L is length(X)*nsamp.

• If the input X is a matrix, the function processes each column as an independent channel and the output is an L-by-M matrix, where L is size(X,1)*nsamp and M is size(X,2).

The data type is the same as that of X.

Version History

Introduced before R2006a