Rohde & Schwarz SMIQ02B - Modulation Π;4 Dqpsk; Table 2-4 Phase Shifts for;4 DQPSK Without Coding; Table 2-4 Phase Shifts for Π; Table 2-5 Phase Shifts for;4 DQPSK with Coding NADC, PDC, PHS, TETRA or APCO25

Digital Modulation SMIQ
1125.5555.03 E-92.88
For offset QPSK (OQPSK), the Q signal is delayed by half the symbol period with reference to the I
signal.
QAM modulation methods 16QAM, 32QAM, 64QAM and 256QAM were implemented according to ETSI
standard ETS 300429 for Digital Video Broadcasting (DVB).
All PSK and QAM modulation methods can be combined with COS and SQR_COS baseband filters as
well as with IS-95 filters. A combination with GAUSS and BESSEL filters is not possible.
2.10.1.2 Modulation π
ππ
π/4DQPSK
With differential coding switched on at the same time, a constellation diagram is obtained for π/4DQPSK
which is similar to that obtained for 8PSK. Phase shifts are however assigned to the individual
modulation symbols. The following tables show the assignment of modulation symbols to phase shifts of
IQ vectors at the selected coding.
Table 2-4 Phase shifts for
π/4DQPSK without coding
Modulation symbol d
n
(binary indication: MSB, LSB)
00 01 10 11
Phase shift ϕ
ϕϕ
ϕ
+ 45° +135° -135° -45°
Table 2-5 Phase shifts for π/4DQPSK with coding NADC, PDC, PHS, TETRA or APCO25
Modulation symbol d
n
(binary display: MSB, LSB)
00 01 10 11
Phase shift ϕ
ϕϕ
ϕ
+ 45° +135° -45° -135°
Table 2-6 Phase shifts for π/4DQPSK with coding TFTS
Modulation symbol d
n
(binary display: MSB, LSB)
00 01 10 11
Phase shift ϕ
ϕϕ
ϕ
- 135° +135° -45° +45°