Rohde & Schwarz SMU200A - External Baseband Signal - Baseband Input

Instrument Function
R&S
®
SMU200A
436Operating Manual 1007.9845.32 ─ 15
User Marker / AUX I/O Settings
Calls the "User Marker AUX I/O Settings" menu, used used to map the connector on the
rear of the instruments.
See also chapter 5.2.3.12, "User Marker / AUX I/O Settings", on page 140.
5.9 External Baseband Signal - Baseband Input
The R&S Signal Generator makes it possible to feed an external analog or digital base-
band signal into the signal path.
User-specific wanted signals or interference signals can thus be added to internally gen-
erated signals and subsequently - provided the instrument is fitted with the required
options - be faded, detuned or loaded with noise (see description "Fading Simulator" and
chapter 5.7, "Impairment of Digital I/Q Signal and Noise Generator - AWGN/IMP Block",
on page 288).
An analog signal is fed in via the "I/Q" connectors and then A/D-converted. The complex
analog baseband input bandwidth is 60 MHz, i.e. the I and Q components of the signal
are each filtered with a 30 MHz lowpass.
Digital signals are input via the LVDS interface "Digital Input". An external digital signal
interface module (R&S EX-IQ-Box) can be connected, providing parallel or serial signal
transmission from external devices.
The externally input signal can be added to the internally generated signals and be fre-
quency-shifted as well as loaded with a relative gain.
The equipment options for the basic unit (R&S SMU with frequency option R&S SMU-
B10x) includes option R&S SMU-B17 (Baseband Input digital/analog) and options R&S
SMU-B9/B10/B11 (Baseband Generator) and R&S SMU-B13 (Baseband Main Module).
With two-path instruments, the signal can be routed to path A, path B or to both paths.The
external analog signal can also be directly applied to the I/Q modulator; the I/Q modulation
settings are then made exclusively in the I/Q Mod menu. In this case, the option R&S
SMU-B17 (Baseband Input digital/analog) is not necessary (selection Analog Wideband
I/Q In, see chapter 5.6, "I/Q Modulation - I/Q Mod Block", on page 275).
The range for the sample rate of the external digital signals is 400 Hz to 100 MHz. The
resampler operates in such a way that a baseband signal with a sample rate of less than
100 MHz is interpolated on the 100-MHz sample rate and then used as output.
A sample rate less than 100 MHz must fulfill the following condition:
Sample Rate * 0.31 >= Modulation Bandwidth
With a sample rate of 100 MHz (Sample Rate Source "User Defined"), the modulation
bandwidth has a value of 40 MHz.
External Baseband Signal - Baseband Input