Atec Rohde-Schwarz-SML03 - Manual (Page 5)

Signal Generator ¸SML 5
Wide frequency range
The ¸SML has a lower frequency
limit of 9 kHz as standard and thus fully
covers the frequency range required for
EMC measurements.
Reference source
The ¸SML allows the mode of fre-
quency generation to be selected. In the
Extended Divider Range mode, the RF sig-
nal is generated by frequency division.
The excellent values obtained in this
mode for SSB phase noise are compara-
ble with the high-grade crystal oscillators
normally used as reference sources from
10 MHz to 30 MHz.
Compared to crystal oscillators, the
¸SML provides the following bene-
fits:
◆
Frequency can be set in 0.1 Hz steps
and synchronized to an external
reference
◆
All functions can be remotely
controlled via the IEC/IEEE bus or
serial interface
Offset from carrier SSB phase noise, typical values
1 Hz –95 dB
10 Hz –120 dB
100 Hz –130 dB
1 kHz –138 dB
10 kHz –148 dB
Generation of stereo and
RDS signals
FM stereo broadcasting is still the major
audio medium – especially in the auto-
mobile sector, where millions of car
radios are produced every year. With its
integration into mobile radio telephones,
FM broadcasting becomes even more sig-
nificant. For testing FM stereo receivers,
audio test signals are modulated onto an
RF carrier and measured after demodula-
tion by the DUT. For the car radio sector,
automotive radio information (ARI) has to
be generated in addition. Test signals are
also needed for the radio data system
(RDS), which has been established in
many countries for a long time.
Stereo/RDS Coder ¸SML-B5
The optional Stereo/RDS Coder
¸SML-B5 meets all the above
requirements. Built into instruments of
the Signal Generator Family ¸SML,
the solution is based on equipment fea-
turing an excellent price/performance
ratio as well as top-class specifications
and providing full coverage of the
frequency range in question.
Audio signals produced by internal
LF generator
The internal LF generator, which is suit-
able for simple receiver tests, is part of
the basic configuration of the ¸SML.
It generates sinusoidal signals at fixed
frequencies, thus allowing basic func-
tional tests to be carried out without an
external signal (see figure on left).
Combination with the
Audio Analyzer ¸UPL
The stereo/RDS coder can also work with
external signals applied to its analog and
digital modulation inputs. Combining
the Signal Generator ¸SML and the
Audio Analyzer ¸UPL (data sheet
PD 0757.2238) creates a general-purpose
test system for FM tuners (see figure on
next page).
The great advantage is the automatic
synchronization of measurement results.
Just as in other two-port audio mea-
surements, the test signals are produced
in the generator section of the Audio
Analyzer ¸UPL, routed through the
modulator and the DUT, and measured in
the analyzer section of the ¸UPL.
Since generation and analysis are opti-
mally timed, measurement times are con-
siderably shorter than with separately
operating instruments.
Use in production
Combining the Signal Generator
¸SML and the Audio Analyzer
¸UPL enables measurements to be
automated. The Universal Sequence
Control ¸UPL-B10 allows complete
test programs to be generated and run on
the ¸UPL, in which case the Signal
Generator ¸SML with the
¸SML-B5 option is remote-controlled
via the IEC60625 or RS-232-C interface.
In most production environments, the
complete test set can be run under an
external controller.
SSB phase noise at 9.5 MHz output
frequency, extended divider range acti-
vated, 1 Hz measurement bandwidth.
RF-modulated test signal
including ARI and RDS
Signal Generator ¸SML+Stereo/RDS Coder ¸SML-B5
FM stereo tuner
Audio signals produced by the built-in
LF generator of the ¸SML.