Rohde & Schwarz SMB 100a - RF Frequency

RF Signal - RF R&S SMB
1407.0806.32 4.26 E-2
Instruments connected downstream can be taken into consideration when setting the frequency and
level by entering a frequency and/or level offset.
Automatic level control ensures maximum level accuracy.
User-specific lists which contain level correction values for any frequency range (User Correction) can
be created to, for example, compensate the cable attenuation in a test assembly setup.
The RF signal can be also generated in modulated form. An internal LF generator, internal pulse
generator and/or the external modulation inputs MOD EXT at the front and PULSE EXT at the back of
the instrument are available as the source for the analog modulations.
An external trigger signal for the sweeps can be provided at the INST TRIG input. The input REF IN is
used to input an external instrument reference frequency, and the output REF OUT serves as the
output of the reference frequency (internal or external).
RF Frequency
The simplest way to set the RF frequency is to enter it directly in the header of the display.
The entry is activated by pressing the
FREQ key. Changes to the frequency have an immediate effect
(without confirmation with the Enter key) on the output signal.
Remote-control command
SOUR:FREQ 100 MHz
Note:
The IEC/IEEE-bus command sets the level of the Freq display, i.e. an entered frequency offset is
taken into consideration in the frequency value (see below).
The frequency entered and displayed in the frequency entry field takes any set frequency offset into
consideration, e.g. an offset set for a downstream instrument. This means that with a frequency offset
the frequency displayed in the header does not correspond to the frequency at the RF output, but rather
to the frequency at the output of the downstream instrument. A set frequency offset is indicated by the
FREQ OFFSET status message.
This allows the desired frequency at the output of a downstream instrument to be entered in the
frequency field. The R&S SMB Signal Generator changes the RF output frequency according to the
entered offset.
However, the frequency entered and displayed in the Frequency menu of the RF function block always
corresponds to the RF output frequency. Any frequency offset is not taken into consideration.
The correlation is as follows:
Freq in header = RF output frequency (= Freq in menu) + Freq offset (= Offset in menu)
Frequency offset by the instrument
(
Offset
in the Frequency menu)
RF output frequency
(
Frequency
in the Frequency menu)
Mixer
(
Freq
in the header
area of the screen)
Frequency at the output
of the instrument
The frequency offset is entered in the Frequency menu. Here it is also possible to set the frequency
without taking the offset into consideration, to set the step width for the frequency entry using the rotary
knob, and to set the phase for the RF output signal.