Documentation

This is machine translation

Translated by Microsoft
Mouseover text to see original. Click the button below to return to the English verison of the page.

Note: This page has been translated by MathWorks. Please click here
To view all translated materals including this page, select Japan from the country navigator on the bottom of this page.

ammod

Amplitude modulation

Syntax

y = ammod(x,Fc,Fs)
y = ammod(x,Fc,Fs,ini_phase)
y = ammod(x,Fc,Fs,ini_phase,carramp)

Description

y = ammod(x,Fc,Fs) uses the message signal x to modulate a carrier signal with frequency Fc (Hz) using amplitude modulation. The carrier signal and x have sample frequency Fs (Hz). The modulated signal has zero initial phase and zero carrier amplitude, so the result is suppressed-carrier modulation.

    Note:   The x, Fc, and Fs input arguments must satisfy Fs > 2(Fc + BW), where BW is the bandwidth of the modulating signal x.

y = ammod(x,Fc,Fs,ini_phase) specifies the initial phase in the modulated signal y in radians.

y = ammod(x,Fc,Fs,ini_phase,carramp) performs transmitted-carrier modulation instead of suppressed-carrier modulation. The carrier amplitude is carramp.

Examples

collapse all

Set the sample rate to 100 Hz. Create a time vector 100 seconds long.

fs = 100;
t = (0:1/fs:100)';

Set the carrier frequency to 10 Hz. Generate a sinusoidal signal.

fc = 10;
x = sin(2*pi*t);

Modulate x using single- and double-sideband AM.

ydouble = ammod(x,fc,fs);
ysingle = ssbmod(x,fc,fs);

Create a spectrum analyzer object to plot the spectra of the two signals. Plot the spectrum of the double-sideband signal.

sa = dsp.SpectrumAnalyzer('SampleRate',fs, ...
    'PlotAsTwoSidedSpectrum',false, ...
    'YLimits',[-60 40]);
step(sa,ydouble)

Plot the single-sideband spectrum.

step(sa,ysingle)

See Also

| | |

Introduced before R2006a

Was this topic helpful?