User's Manual

Table Of Contents
WiNRADiO G39DDC User’s Guide
25
not be possible as the computer may then become sluggish and the
application may freeze”.
The chunk of the IF spectrum as seen and processed by the primary
downconverter (DDC1) is shown at top-left; this is called the DDC1 spectrum.
Its bandwidth is determined by the DDC1 control at the top of the DDC1
spectrum:
Anywhere within the primary downconverter spectrum, you can place the
secondary downconverter (DDC2) to further refine and narrow-down the
portion of spectrum you wish to work with. The maximum DDC2 bandwidth is
320 kHz. The DDC1 bandwidth must be always greater than (or equal to)
DDC2 bandwidth, and the bandwidths will adjust themselves automatically to
comply with this rule, if one of them is changed.
The spectrum display at top right of the application window shows the
spectrum as seen and acted upon by the secondary downconverter (DDC2).
This spectrum represents the output of the final decimation process
(performed inside the actual receiver, i.e. inside its FPGA) and is available for
final filtering and demodulation that is performed entirely outside of the
receiver hardware, by the PC application.