R&S SMJ100A, Руководство по эксплуатации

Страница: 298 / 874

Instrument Function
R&S
®
SMJ100A
282 Operating Manual 1403.7458.32 ─ 14
5.6 I/Q Modulation - I/Q Mod Block
The R&S SMJ offers I/Q modulation with:
●
external analog I/Q signals,
●
internal digital signals.
I/Q modulation with an external analog I/Q signal is possible for the basic unit
(R&S
SMJ with frequency option R&S SMJ-B10x) without additional equipment
options.
The basic equipment configuration for generating an internal baseband signal includes
the options R&S
SMJ-B13 (Baseband Main Module) and R&S SMJ-B9/B10/B11 (Uni-
cod and ARB).
The internally generated baseband signal is configured in the Baseband function block
(see
Chapter 5.8, "Baseband Signal - Baseband Block" , on page 313). Before the sig-
nal is fed into the I/Q modulator, noise can be added and/or the signal can be impaired.
Impairment at this point along the signal flow is offered to allow a signal to be output at
the I/Q-OUT outputs (a signal which, for example, compensates signal distortion in a
connected test object (DUT)).
Impairment is integrated in the basic unit. The generation of noise requires the option
R&S
SMJ-K62 (AWGN).
Impairments can also be set in the I/Q Mod menu to allow an externally applied analog
I/Q signal to be impaired. An internal baseband signal can thus be impaired both digital
(in the Impairment block in the Impairment menu) and analog in the I/Q modulator. If
impairments are set in both menus, they superimpose each other in the signal.
5.6.1 I/Q Modulator
To select the input signal of the I/Q modulator and to open the "I/Q Settings" menu,
select "I/Q Mod > Configure".
The "I/Q Settings" menu containing the modulation settings is opened in the top sec-
tion (see
Chapter 5.6, "I/Q Modulation - I/Q Mod Block" , on page 282).
Use the "I/Q Mod In" section to select the input signal:
●
select "Analog Wideband I/Q In", if the external analog signal is fed into the I/Q
modulator.
The maximum available RF bandwidth is described in the instruments specifica-
tions (see data sheet).
I/Q Modulation - I/Q Mod Block