Instrument Function
R&S
®
SMBV100A
345Operating Manual 1176.8016.02 ─ 17
2 0
3 1
By means of differential coding, the assignment between modulation symbols and
phase differences shown in the following table is generated:
Modulation sym-
bol a
n
(binary,
MSB, LSB)
00 01 10 11
Phase difference 0° 90° 180° 270°
Example: Gray and differential coding for 8PSK modulation
First, a gray coding is performed according to the gray code. Afterwards, a differential
coding is performed according to the recursive coding algorithm quoted above. The
assignment between modulation symbols and phase differences shown in the following
table is generated:
"Differential coding according to VDL" can be used for modulation types with 3 bits/
symbol, e.g. 8PSK.
Table 5-6: Differential coding according to VDL
Modulation symbol d
n
000 001 010 011 100 101 110 111
Phase difference 0° 45° 135° 90° 270° 315° 225° 180°
"Phase differential coding" INMARSAT and PHASE DIFF correspond to system stand-
ards Inmarsat-M and DVB according to ETS 300 429. The INMARSAT coding can gen-
erally be used for modulation types with 2 bits/symbol, such as QPSK. It uses the fol-
lowing algorithm.
5.9.3.4 Baseband Filter - Custom Digital Mod
The R&S SMBV offers a wide selection of predefined baseband filters. The filter char-
acteristic for the selected filter is displayed in the "More..." submenu in the "Filter"
menu section (see "Filter" on page 360). Additionally, a user defined filter can be
selected (see "User filter" on page 350).
The following table shows the filters that are available, together with the associated
parameters and remote control commands. The filter characteristic is displayed in
graphical form.
Baseband Signal - Baseband Block
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