With the standard WR-G315e receiver, the FMW mode button is disabled and the wide FM demodulation mode
is not available. This is because wide FM demodulation cannot be provided within
the signal-processing constraints of the WR-G315e software-defined narrow-band receiver architecture.
However, wide-band FM demodulation capability is available as a factory-installed option.
The wide-band FM demodulator option is in fact a self-contained "hardware-defined" receiver which shares only the main receiver's front-end
and first mixer, but has an independent wide-band analog processing circuit with a conventional "hardwired" demodulator.
If the Wide FM Option is installed, the FMW button becomes active. The demodulator spectrum display
shows real-time spectrum of the demodulated audio. There is also a user-definable
audio filter, displayed superimposed over the audio spectrum and graphically adjustable.
The order code for a receiver with the Wide-FM Option installed is WR-G315e/WFM.