Configuring the RF Signal
R&S
®
SMW200A
483User Manual 1175.6632.02 ─ 30
The instrument cannot verify the frequency of the oscillator signal that is fed in. We
recommend that you fed in signal with exactly the same frequency as shown in the set-
tings dialog, see LO OUT Frequency.
Level adjustment
The level range of the LO input and LO output signal is 10 dBm ±3 dB, as specified in
the data sheet of the R&S SMW.
The instrument uses the default settings to adjust its internal level, which is sufficiently
accurate for most applications.
But consider that the oscillator signal level at LO IN should be stable, with minimized
phase noise and interferences. The fed in signal is directly used in the instrument, and
thus affects the instrument performance. We recommend that you keep the (sub-)har-
monics below -20 dBc, and the level stable within ±0.1 dB over time and temperature
However, if you need optimum performance, or if you have long interconnections
between LO OUT and LO IN, we recommend that you adjust the LO level at the cur-
rent frequency. Using this function, the instrument readjusts the internal signal levels to
optimum.
The adjustment may take a few milli seconds.
Keep the order when performing LO Level adjustments for subsequent instru-
ments
When you perform LO level adjustments in several interconnected signal generators,
always start with the first Rohde & Schwarz signal generator, and continue in the order
of the following Rohde & Schwarz signal generators. This sequence is necessary,
because the second instrument adjusts its internal gain as long as the levels are accu-
rate and then keeps this adjustment untouched. If you now would change the prede-
cessor, the level of the second would change accordingly and its adjustment would no
longer be correct.
8.6.1 Required Options
The equipment layout for using the LO Coupling function is included in:
●
Option Phase Coherence (R&S SMW-B90)
8.6.2 Phase Coherence
Phase coherence of RF signals designates a defined, constant delta phase between
two or more RF carrier signals with the same frequency or a multiple of the frequency.
Local Oscillator Coupling
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