02-12-2008 08:44 PM
02-13-2008 07:04 PM - edited 02-13-2008 07:07 PM
Hi
The bit stream use to generate the FSK signal in this example is a pseudo random sequence. If you go inside the custom subvi “mod_Create Continuous FSK” you can see how the example generates the bit stream.

As you can see in the picture the subvis use to generate the FSK signal are called “MT Generate Filter Coefficients”: Calculates filter coefficients for pulse shaping and matched filters applied by the digital modulation and demodulation VIs. The calculated filter coefficients are used during modulation to reduce the bandwidth of the transmitted signal, and during demodulation to reduce intersymbol interference. The other function is call “MT Modulate FSK”: Inputs a sequence of data bits, performs FSK modulation, and returns the modulated complex baseband waveform in the output complex waveform parameter.

A similar case liek yours was addressed by one of my partners. He developed a simple example that generates the FSK signal from an 8 bit integer array. Please take a look at the examples.
A very good resource is the article in Devzone: RF Hardware Example: Frequency Shift Keying.