WiNRADiO G33DDC User’s Manual
95
For SINAD and THD, the test frequency is assumed to be 1 kHz.
Using the SINAD measurement facility, you can measure the sensitivity
of the WiNRADiO Excalibur Pro receiver very easily. All you need is a
calibrated signal generator. For example, to measure AM sensitivity,
connect the signal generator to the antenna input and turn on AM
modulation (the modulation depth is usually set to 30%, although some
manufacturers prefer to quote sensitivity figures at higher modulation
depths, for example 60 or 80%). Set the Test frequency equal to the
modulating frequency (typically 400 Hz or 1 kHz). Adjust the IF
bandwidth for the maximum SINAD. Then gradually keep reducing the
generator output level to the point when SINAD drops to 10 dB. The
receiver sensitivity is then equal to the generator level at this point.
Measuring AM sensitivity using SINAD rather than the conventionally
used S+N/N is quite appropriate as SINAD also includes distortion, which
is as much an impediment to intelligible reception as noise, and
therefore provides a more practical result. Even though in theory using
SINAD should result in the sensitivity figures being somewhat worse
than if S+N/N is used, in practice, with a good receiver such as the
Excalibur Pro, there is no noticeable difference.
Show Data Rates
The Show Data Rates display shows the various internal data rates of the
entire G33DDC receiver system. This may be useful especially for debugging
of installation problems:
