R&S 1129.7246.03, Operating Manual

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Operating Manual 1302.6163.12 - 03 4.33
R&S ESU Instrument Functions
Receiver Mode
4.5.4.3 AF Demodulators
The R&S ESU provides demodulators for AM and FM signals. With these demodu-
lators selected, a displayed signal can be monitored using the internal loudspeaker
or external headphones.
DEMOD The DEMOD softkey calls a submenu in which the desired type of demodulation can
be switched on.
The volume for loudspeaker and headphones is set by means of control knob on the
front panel. The volume can also be remote-controlled (remote command
SYST:
SPE:VOL 0.7
).
A squelch function enables the input of a level threshold below which the audible AF
is cut off.
This softkey is also available in the RECEIVER / MEAS menu.
DEMOD
ON | OFF
The DEMOD ON | OFF softkey switches demodulation on/off.
Remote command:
DEM OFF
(
DEModulation ON
automatically switched on with
DEM AM | FM
)
AM | FM The AM and FM softkeys can be activated one at a time. They are used to set the
desired demodulation type, FM or AM.
Remote command:
DEM AM
SQUELCH The SQUELCH softkey enables the input of a level threshold below which the audi-
ble AF is cut off. The squelch function is associated with the internal trigger function
(
TRIGGER menu), which will be switched on automatically with the squelch.
Squelch level and trigger level do have the same value.
The default setting for the squelch is off.
Remote command:
SENS:DEM:SQU ON
SENS:DEM:SQU:LEV 80 PCT
4.5.4.4 Data Reduction and Peak List
EMI measurements may involve much time because the time constants prescribed
by the standard for the quasipeak weighting require transients which lead to long
measurement times per each value. In addition, the standards stipulate procedures
for finding local EMI maxima such as shifting the absorbing clamp, variation of the
test antenna height and rotating the DUT. Measuring with quasipeak weighting at
each frequency and for each setting of the test configuration would lead to unac-
ceptably long measurement times. For this reason, R&S has developed a method
which reduces the time-consuming measurements to a minimum with an optimum
reliability of detection.
DEMOD ON | OFF
AM | FM
SQUELCH