NBFM

This objects implements an analog NBFM modulator/demodulator.
It can be used as an automatic demodulator for the DDC object.

Object NBFM {
    constructor NBFM( String aname );
    bool configure( {'modulation_index': number });
    IQData modulate( Samples input );
    FloatData demodulate( IQData in );
}

This object can be used with the Digital Down Converter

.configure

Defines the modulation index for the modulator/demodulator. The default value is internally set to 0.25.

    modem.configure( {'modulation_index': 0.2} );

.modulate

This method needs a FloatData object input containing real (non-complex) data for modulation (you may use the getReal() or getImag() methods of IQData objects).

      IQData iq = modem.modulate( FloatData blockIn );

.demodulate

    FloatData symbols = modem.demodulate( IQData );

Example

var audio = new IQData('audio');
if( !audio.loadFromFile('lamableu.wav')) {
     print('file not found.');
     exit();
}
// retrieve channel (mono audio)
var speak = audio.getReal();

// now generate IQ signal from FM audio
var fm = new NBFM('modulator'); 
fm.configure( {'modulation_index': 0.1} );
var IQ = fm.modulate( speak );

Last update: December 1, 2021