DADiSP Worksheet Functions > Function Categories > Fourier Transforms and Signal Processing > MODAM

 

MODAM

Purpose:

Performs amplitude modulation of a series.

Syntax:

MODAM(series, fc)

series

-

A series, the input to modulate.

fc

-

Optional, a real. The carrier frequency. Defaults to rate(series)/4.

Returns:

A series, the amplitude modulated output.

Example:

W1: gtriwave(1000,.001, 4)

W2: modam(w1, 200)

W3: demodam(w2, 200)

W4: specgram(w2, 64, 63, 1024)

 

The triangle series of W1 is amplitude modulated with a carrier frequency of 200 Hz in W2. W3 recovers the modulated series and W4 displays the joint time-frequency plot of the frequency modulated series.

Example:

W1: gtriwave(1000,.001, 4)

W2: modam(w1, 300)

W3: demodam(w2, 300)

W4: specgram(w2, 64, 63, 1024)

 

Same as above except the carrier frequency is 300 Hz.

Remarks:

The carrier frequency should be greater than or equal to the bandwidth of the input series but less than or equal to rate(series) / 2, the Nyquist frequency.

 

See DEMODAM to demodulate an amplitude modulated series.

 

See MODFM to frequency modulate a series.

See Also:

DEMODAM

DEMODFM

MODFM