Hameg HM5510 Mode D'emploi page 38

C o n t r o l s a n d c o n n e c t i o n
In the 0 dB position the maximum signal level
which can be displayed will be –30 dBm, but this
setting should be avoided resp. only used if
necessary.
Please note:
In order to protect the delicate input stage the 0 dB
position can only be accessed out of the 10 dB
position and after pressing the 0 dB pushbutton for
STOP STOP
a long time.
The maximum permissible input levels must not
be exceeded, otherwise the input stage may be
destroyed. The spectrum analyzer displays in
general only such frequencies inside its limits of
150 kHz to 1050 MHz, however, it is possible that
the input signal contains high levels of hf outside
these limits!
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VBW – Video filter
This filter averages the noise and thus will in general
reduce it, this may make small signals visible.
STOP
As the response time of filters precludes too fast a
sweep a large span may not be acceptable with the
video filter switched in; this will be indicated by
UNCAL. If this message is shown reduce the span.
First use CENTER FREQ. to shift the signal to the
TiPP display center, then reduce the span.
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RBW – Choice of resolution bandwidths 500 or 20 kHz.
The respective LED will indicate which was selected.
Depending on the IF bandwidth the spectrum analyzer will
be able to more or less separate frequencies. E.g. at 20
kHz RBW 2 signals 40 kHz apart can be recognized as se-
parate; at 500 Kkz RBW both would melt into one signal.
However, the smaller bandwidth requires a slower sweep,
otherwise the filter output can not rise to its correct value,
hence the amplitude shown will be too small. In case the 4
kHz video filter is also switched in the span must be furt-
her reduced. UNCAL in the display will be shown if the
sweep is too fast. Of, course, as the noise depends on
bandwidth a smaller bandwidth will decrease it.
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SPAN- The span ist the frequency range displayed on
screen, 1 to 1000 MHz.
In order to change the span the pushbuttons up or down
must be used. The span will be increased from zero in steps
of 1 – 2 – 5 up to full span 1 GHz.
Except for zero span the frequency range on the screen is
determined by the span and the center frequency selected.
Example:
Center frequency 300 MHz, span 500 MHz:
The sweep starts at 50 MHz at the lefthand side of the
screen and moves up to 550 MHz on the righthand side.
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Subject to change without notice
(50 MHz = 300 MHz – ½ span and 550 MHz = 300 MHz + ½
span.)
Please note:
If the span is too large with respect to the RBW (and VBW)
false amplitude levels result, indicated by UNCAL in the
display. At 500 MHz and 1 GHz span this will always be the
case. If UNCAL is shown move the signal first to the center
and then reduce the span until the UNCAL disappears.
ZERO SPAN: press the lower pushbutton until the display
shows ZERO-SP.
In zero span mode the analyzer acts like a selective
voltmeter which measures the frequency selected by CEN-
TER FREQ.
In order to exit zero span press one of the span pushbuttons
shortly, the instrument will return to the span selected
before entering zero span.
FULL SPAN: press the upper pushbutton until the display
shows S1GHz .
In order to exit this setting press one of the two pushbuttons
shortly, the instrument will return to the former span
setting.
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OUTPUT 50Ω – N connector, of the tracking generator.
(HM 5511)
With the tracking generator turned on by TRACK.GEN. ON
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a sine wave signal between –50 to 0 dBm is available
here, the frequency of which is identical to the center
frequency selected.
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OUTPUT 50Ω – N connector, Test signal output (HM 5510)
If this output is activated a 10 MHz signal of 0 ±3 dBm is
available here. This may be connected to the analyzer input
and displayed.
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TRACK.GEN. – Tracking generator (HM5511). After turn-
on the TG is always disabled, the LED is dark.
The TG is turned on by pressing the pushbutton
LED wil light up. By pressing again it will be turned off.
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, the