WiNRADiO G305 User’s Manual
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Appendix D - Inside WR-G305
Technically minded users may like to explore the WiNRADiO G305 Receiver
and experiment with some of the innovative concepts of
Software Defined
Radio
.
The WiNRADiO G305 Receiver is the world’s first commercially available
Software Defined Radio
for the VHF/UHF bands, where the demodulator
function is fully performed in software running on a standard PC. The potential
for experimentation is therefore substantial. This receiver and its software
have been indeed designed to promote and encourage such experimentation.
The WiNRADiO G305 receiver represents only one half of the entire radio. The
other half is your PC. The receiver hardware contains the following functional
blocks:
The incoming signal from the antenna (in the 9 kHz to 1800 MHz range) is
filtered and amplified, then fed into a mixer. Here it is mixed with the first LO
(local oscillator), which is performed by a DDS (Direct Digital Synthesizer),
with a PLL (Phase Locked Loop). The resulting 109.65 MHz intermediate
frequency is filtered using a 4-pole crystal filter with an IF bandwidth of 15 kHz,
and then amplified.
The second mixer again uses a DDS with a PLL to mix the 109.65 MHz signal
down to the last intermediate frequency, which is 12 kHz.
