Applying I/Q Vector Modulation
R&S
®
SMBV100B
280
User Manual 1178.4460.02 ─ 03
I/Q Swap
Selects normal or swapped I/Q control for the generated signal.
The I/Q modulator defined in the IS2000 standard differs from the definition in this
implementation. The definition on which the implementation is based is used by virtu-
ally all digital communication standards, except IS95 and IS2000.
In the final step, the filtered IQ signal is modulated to the desired RF in a different way
in the I/Q modulator:
Figure 5-1: Definition of I/Q modulator in IS2000 and the R&S
SMBV100B
IS2000
= the RF signal s(t) is derived from the baseband I/Q signal as s(t)=i(t)cos(2*pi*f
c
t) +
q(t)sin(2*pi*f
c
t)
R&S
SMBVB = the RF signal s(t) is based on the definition s(t)=i(t)cos(2*pi*f
c
t) - q(t)sin(2*pi*f
c
t)
See also:
●
Description "CDMA2000
®
incl. EV-DV Digital Standard for R&S
SMBV100B"
●
Description "1xEV-DO Rev. A, Rev. B Digital Standard for R&S
SMBV100B"
"Off"
I/Q control is normal.
"On"
The modulation sidebands are inverted by swapping the I and Q sig-
nals (the Q-part of the signal is inverted).
The generated baseband signal is according to CDMA200 and 1xEV-
DO standards.
An I/Q modulator defined according to these standards can cope with
the RF signal generated by the R&S
SMBV100B.
Remote command:
I/Q Wideband
Activates/deactivates optimization for wideband modulation signals (higher I/Q modula-
tion bandwidth).
The modulation frequency response of the R&S
SMBV100B in the useful bandwidth is
improved at the expense of poorer harmonic suppression. This improvement is ach-
ieved by shifting the switching frequencies of the lowpass filters in the output section.
Remote command:
I/Q Modulator Settings
