DEMODFM

Purpose:

Demodulates an FM series using the Hilbert Transform.

Syntax:

DEMODFM(series, fmin, fmax)

series	-	A series or table.
fmin	-	Optional. A real, the minimum modulation frequency used to scale the result. If not specified, no output scaling is performed.
fmax	-	Optional. A real, the maximum modulation frequency used to scale the result. If not specified, no output scaling is performed.

Returns:

A series or array.

Example:

W1: gtriwave(1000,.001, 4)

W2: W1 * 100 + 20

W3: cos(integ(2*pi*W2))

W4: demodfm(W3)

$image\demodfmpic.gif$

W2 represents the scaled information signal and W3 is the resulting frequency modulated signal. The amplitude of W2 determines the instantaneous frequency of W3. The instantaneous frequency of W3 ranges from:

min(w3) == 20 Hz

max(w3) == 120 Hz

W4 is the unscaled demodulated result.

Example:

W1: gtriwave(1000, .001, 4)

W2: modfm(w1, 20, 100)

W3: demodfm(w2)

W4: demodfm(w2, 20, 100)

Same as above except the minimum and maximum modulation frequencies are specified in W4 to scale the result.

Remarks:

DEMODFM uses HILB to calculate the Hilbert Transform.

See MODFM to frequency modulate a series.

See GSWEEP to generate a linearly swept sinewave.

See DEMODAM to demodulate an amplitude modulated series.

DEMODFM

Purpose:

Syntax:

Returns:

Example:

Example:

Remarks:

See Also: