User's Manual

Table Of Contents
WiNRADiO G39DDC User’s Guide
26
The dark blue rectangular area inside DDC1 spectrum corresponds to the
DDC2 bandwidth, while the grey area inside both the DDC1 and DDC2
spectrum relates to the demodulator filter bandwidth. This bandwidth
represents the selectivity bandwidth of the entire receiver and, for the best
signal-to-noise ratio of the received signal, you might wish to adjust this
bandwidth to very closely embrace the visible spectrum of the received signal.
You can do this either using the DEM BW control, or by dragging the edges of
the grey area in the DDC2 spectrum.
You can also drag these areas sideways, by clicking and dragging at their
centre or anywhere inside them, in both the DDC1 and DDC2 spectrum. This
is equivalent to the IF Shift function in conventional receivers.
Clicking on any of the spectrum scopes will cause the receiver to tune to the
corresponding frequency. But as the WiNRADiO Excelsior consists of two
receivers in one, this does have some ramifications which will be further
explained in the following chapters.
If you are a newcomer to software-defined receivers and need a little more
detailed background information on software-defined receivers and digital
down-conversion, please read our SDR and DDC Primer in Appendix A.