Configuring the Internal Baseband Source
R&S
®
SMW200A
387User Manual 1175.6632.02 ─ 16
Gain
Enters the relative gain for the external or internal baseband signal compared with the
signals of the other baseband sources. The gain affects the signal on the output of the
"BB Input" block.
Refer to Chapter 4.12.1.3, "Impact of the Gain", on page 385 for detailed information.
Remote command:
[:SOURce<hw>]:BB:PGAin on page 888
[:SOURce<hw>]:BBIN:PGAin on page 888
4.12.3 How to Improve Signal Characteristics by Shifting the Wanted
Baseband Signal
Shifting of the generated baseband signal is useful in the following cases:
●
You analyze the generated signal with a signal analyzer and the displayed signal
spectrum indicates a carrier leakage (a signal drop) at the current RF frequency.
Shifting the baseband signal to a different center frequency can eliminate the car-
rier leakage problem.
Alternatively, apply an I and/or Q offset and vary the settings until the observed sig-
nal drop disappears, see "To optimize the carrier leakage suppression"
on page 413.
●
You generate a test signal as a sum of two basebands with overlapping spectra,
for example two internal baseband signals (baseband A and baseband B), an inter-
nal and an externally supplied baseband signals, and you route the sum signal to
the same RF output with the same RF frequency.
– Shifting one of the basebands allows you to analyze them both
– Shifting both baseband signals with the same frequency offset results in a sig-
nal with carrier frequency in the center of the RF bandwidth
In the following examples, we assume that:
●
The R&S SMW generates a baseband signal
Shifting and Boosting the Baseband Signal
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