| The following factory-fitted hardware options are available for WR-G315i receiver:
Wide-FM Demodulator Option (/WFM)
With the standard WR-G315i 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-G315i 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-G315i/WFM.
External Reference Oscillator Input Option (/XR)
The G315i/XR receiver includes an additional external SMA connector, which can be used to connect an external reference oscillator for the highest possible frequency accuracy. This external oscillator can be any frequency from 8 to 20 MHz (the user specifies this frequency via software). The input is AC coupled and has an internal impedance of 150 ohm. The reference oscillator can be either sine or square wave between 100 mV to 5 V peak-to-peak.
Reference Oscillator Output Option (/RO)
The G315i/RO receiver includes an additional external SMA connector, which can be used to output the internal reference frequency. This is useful for situations when the receiver's own internal oscillator is to be used as a reference for other equipment, or, if an external reference is used, to provide this external reference to other receivers in a daisy-chain arrangement. If the receiver relies on its internal reference oscillator, this option will provide 16.384 MHz reference output. If an external oscillator is used, then the external oscillator frequency will be provided at this output. The output is DC coupled, sine-wave at HCMOS levels (i.e. approx 0.6 to 4 V peak-to-peak) with an internal impedance of 150 ohm. It can be directly connected to an external reference oscillator input of another WR-G315i receiver.
Intermediate Frequency 109.65 MHz Output Option (/IF0)
The G315i/IF0 receiver includes an external SMA connector, which provides a wide-band IF output (prior to the roofing filters) at the first intermediate frequency of 109.65 MHz.
Intermediate Frequency 10.7 MHz Output Option (/IF1)
As an alternative to the previous option, the G315i/IF1 receiver provides a wide-band IF output. The difference is that this option involves an additional internal down-converter which converts the 109.65 MHz IF down to 10.7 MHz.
Intermediate Frequency 16 kHz Output Option (/IF2)
This G315i/IF2 receiver provides a narrow-band IF output at 16 kHz, its bandwidth limited by the receiver's 20 kHz roofing filter. This is a useful option for low-cost experiments with Software Defined Radio concepts, because the frequency is low enough to be digitized by a standard PC sound card.