R&S 1129.7246.03, Operating Manual

Page: 364 / 855

Operating Manual 1302.6163.12 - 03 4.333
R&S ESU Instrument Functions
External Generator Control – Option R&S FSP-B10
4.11 External Generator Control – Option R&S FSP-B10
The external generator control option permits to operate a number of commercially
available generators as tracking generator on the R&S ESU. Thus, scalar network
analysis with the R&S ESU is also possible outside the frequency range of the inter-
nal tracking generator when the appropriate generators are used.
The R&S ESU also permits to set a frequency offset for frequency-converting mea-
surements when external generators are used. For harmonics measurements or fre-
quency-converting measurements, it is also possible to enter a factor, by which the
generator frequency is increased or reduced compared with the receive frequency
of the R&S ESU. Only make sure that the resulting generator frequencies do not
exceed the allowed setting range of the generator.
The level range to be set also depends on the generator used.
The generator is controlled via the – optional – second GPIB interface of the
R&S ESU (= IEC2, supplied with the option) and, with some Rohde & Schwarz gen-
erators, additionally via the TTL synchronization interface included in the AUX inter-
face of the R&S ESU.
Therefore, the frequency sweep differs according to the capabilities of the generator
used:
• In the case of generators without TTL interface, the generator frequency is first set
for each frequency point via GPIB, then the setting procedure has to be completed
before recording of measured values is possible.
• In the case of generators with TTL interface, a list of the frequencies to be set is
entered into the generator before the beginning of the first sweep. Then the sweep
is started and the next frequency point selected by means of the TTL handshake
line TRIGGER. The recording of measured values is only enabled when the
generator signals the end of the setting procedure via the BLANK signal. This
method is considerably faster than pure GPIB control.
With the SELECT GENERATOR softkey, a list of the supported generators with the
frequency and level range as well as the capabilities used is included.
The external generator can be used in all operating modes. Recording of test setup
calibration values (
SOURCE CAL ) and normalization with the correction values
( NORMALIZE ) are only possible in the NETWORK mode.
Like the internal tracking generator, the external generator is activated by means of
the hotkey bar:
MORE hotkey - NETWORK hotkey (for details refer to section “Mode
Selection – Hotkey Bar” on page 4.9 ).
The use of the TTL interface enables considerably higher measurement rates as
pure GPIB control, because the frequency stepping of the R&S ESU is directly
coupled with the frequency stepping of the generator.
In order to enhance measurement accuracy a common reference frequency
should be used for both the R&S ESU and the generator. If no independent 10
MHz reference frequency is available, it is recommended to connect the reference
output of the generator with the reference input of the R&S ESU and to enable
usage of the external Reference on the R&S ESU via
SETUP - REFERENCE
EXT .