Remote; Write A; Copy A B; Test Signal / Level - Hameg Instruments HM5530 Manuel

C o n t r o l s a n d r e a d o u t
If the video fi lter VBW 15 is switched in (VB 4 kHz), the bandwidth is
reduced further.
The measuring signal causes a display of the shape of the combined
fi lters' response (except, of course, in ZERO SPAN mode), because
the analyzer sweeps the frequency across the fi lters' bandpass. The
amplitude shown is equal to the true level unless UNCAL is displayed
in the sweep time readout.
It depends on the if bandwidth (RBW), how well the analyzer can display
two adjacent spectral lines. Two sine wave signals of the same level,
40 kHz apart, e.g. will still be displayed as two separate lines if RBW
= 9 kHz was selected. With RBW = 120 kHz or 1 MHz both lines would
merge into one.
Thus a lower resolution bandwidth (RBW) is equal to a better reso-
lution and will show more details of a signal, but the consequence
is a slower response time of the fi lters. The analyzer automatically
selects a slower sweep, if the span is increased with a given setting
of RBW in order to allow the fi lters more time for reaching the full
amplitude, else the amplitudes shown would be too low. If the slowest
sweep available is still not adequate, UNCAL will be displayed in the
sweep time (SW ... ms) readout fi eld. In order to recur to a calibrated
measurement, the SPAN 4 must be reduced. The slower sweep also
reduces the sweep repetition rate.
A lower bandwidth reduces the noise and thus increases the usable
sensitivity. This will e.g. be visible by switching from 1 MHz to 9 kHz:
the width of the noise band will decrease, and the noise band will shift
downwards.
19 AVG (Average).
This pushbutton activates/deactivates the averaging mode. This function
will only be indicated by the lighted pushbutton, not also in the read-
out. The video signal is continuously being averaged by calculating an
average of preceding and actual values, displaying it, taking this value
and calculating the average of it and the next value etc. This continuous
averaging is evident on the screen. The averaging reinforces recurring
signal components and weakens stochastic components, resulting in a
substantial noise reduction at the expense of waiting for the averaging. In
fact this averaging is nothing else but a further bandwidth reduction.
If this function is selected, the MAX HOLD- and MIN HOLD function
20
will also be active in the background and vice versa, such that it is
possible to switch back and forth between both. If COPY A to B
depressed, the topical indicated averaged signal spectrum made of
memory will transfer from memory A into memory B.
If a parameter e.g. the reference level REF.LEVEL
changed, the averaging is again started.
20
MAX HOLD
This function automatically detects, stores and displays the maximum
of the averaged spectrum. This function is only indicated by the lighted
pushbutton, not also in the readout. Hence the AVG
be automatically also activated, its pushbutton does not light up. It is
possible to switch back and forth between both functions. The function
continuously detects the actual highest value of the averaged signal, its
memory will only be updated if a still higher level should be detected.
This allows the reliable measurement of the peaks even of pulsed sig-
nals. It is, however, necessary to always wait some time and read the
result only after no further increase of the level is discernible.
The function can be disabled by another short depression of the push-
button.
MIN HOLD (push long)
This function automatically detects, stores and displays the minimum
of the averaged spectrum. This function is indicated by the lighted
34
Subject to change without notice
pushbutton. As is the case for the function MAX HOLD is switched on
automatically also with the function MIN HOLD averaging AVG. With a
short depression the pushbutton can be switched by MIN HOLD to MAX
HOLD. With a long depressing the pushbutton can be switched by MAX
HOLD to MIN HOLD. The function continuously detects the actual lowest
value of the averaged signal, its memory will only be updated if a still
lower level should be detected. This allows the reliable measurement
of short signal variations or signal discontinuations. It is, however,
necessary to always wait some time and read the result only after no
further decrease of the level is discernible.
The function can be disabled by twice short depression or by long
depression of the pushbutton.
21 PHONE
STOP
The volume can be adjusted with the tuning knob
indicated in the Readout as percentage quotation in place of the test
signal output level.
22 PHONE
Headphone connector, 3.5 mm jack for headphones with an impedance of
8 Ω . The signal available at this connector comes from an am detector,
>
it helps to identify the sources of interference e.g. when making emi
measurements (precompliance measurements). If an antenna is con-
nected to the analyzer input and zero span selected with SPAN
000.000 MHz), selecting CENTER
analyzer can be tuned to a transmitter. Please note that this operational
mode may be subject to national restrictions!
23 VIEW B
This pushbutton will only light up upon a depression, if a spectrum was
previously stored in memory B by depressing COPY A to B
spectrum will be displayed and a lit pushbutton WRITE A
A – B 24 will extinguish. If no, a warning will be sounded. The memory
B contents will be lost upon turn-off.
24
CALC A – B
This pushbutton will only light up, if a spectrum was previously stored
in memory B, then the difference of spectra A – B will be displayed, any
lit pushbutton WRITE A
was stored in B, a warning will be sounded. The three pushbuttons:
27
is

WRITE A

three spectra in turn.
25

REMOTE

14
is called and This pushbutton is lit if the instrument is under remote control via the
serial interface. By depressing the pushbutton, control is returned to
the front panel.
26
WRITE A
The instrument contains two memories: A and B. In normal mode this
19
function will pushbutton is lit, indicating that the actual spectrum is being written into
memory A and at the same time read out, d/a converted and displayed.
The memory contents will be lost upon turn-off.
27
COPY A
This pushbutton will not light up. Upon depressing it, the actual spec-
trum in memory A will be copied to memory B which is indicated by a
beep. The pushbutton WRITE A
CALC A – B is activated, this function can not be called, a warning will
be sounded.
28

TEST SIGNAL / LEVEL

The adjustment of the test signal level is performed with the tuning
7
knob from –10 to 0 dBm. The level is indicated in the readout fi eld
(TL ... dBm).
In order to realize a rather short fi lter response
for pulsed signals, a small span, RBW = 1 MHz,
VBW = 50 kHz should be selected.
3 and using the tuning knob
26 23
or VIEW B will extinguish. If no spectrum
26 23
, VIEW B , and CALC A – B
B
26
will continue to be lit. If the function
7 . The volume is
4 (SF
7 the
27 . If yes, this
26 or CALC
24
may be used to look at