Specifications

27
Resolution band width (RBW)
The SDU5600 provides four
selectable RBW bandwidths
which are 4kHz, 32kHz, 64kHz
and 128kHz.
Press the RBW key to make the
RBW display appear in reverse
contrast. Rotate the main dial to
select the desired value followed
by MHz or kHz to complete the
selection sequence.
The two plots here show the
results from monitoring the same
signal (80MHz WFM) but using
4kHz and 128kHz RBW
bandwidths respectively.
With the narrower RBW, the finer
signal activity can be observed.
With the wider RBW bandwidth
the resolution becomes coarse
but it can be more suited for
signals with wide bandwidth such
as FM broadcast signal.
The RBW should be chosen
as appropriate for different
monitoring requirements.
As the SDU5600 employs
modern DSP/FFT techniques,
there is no difference in screen
update speed irrespective of
which RBW has been selected.
However, selection of RBW may
affect the displayed signal strength.
When a signal is displayed which is much wider in bandwidth than the currently selected RBW filter,
there will be some inaccuracy in the signal strength displayed. This is because the wider signal will
loose some of its energy after passing through the narrower RBW filter. The same signal may
produce a higher signal strength on the LCD display if it has passed through (more appropriately
selected) wider RBW filter.
Section 5-4-4