Tabor Electronics 5064, User Manual

Page: 267 / 369

5-46
PSK Modulation
Programming
Use the following command for programming the PSK parameters.
The PSK functions use pre-defined table settings. In case the
standard table do not suit the application you can design your own
(n)PSK data using the User PSK data table entry option. Note that
the carrier waveform frequency (CW) setting is common to all
modulation schemes.
PSK:TYPE{BPSK|QPSK|OQPSK|8PSK|16PSK|USER}(?)
Description
This selects between the various (n)PSK modulation schemes.
Parameters
Name Type Default Description
BPSK Discrete BPSK Selects the Binary Phase Shift Keying (BPSK)
modulation type. In this mode, the instrument shifts
from 0

to 180

at a rate determined by the
PSK:BAUD command and in a sequence as
programmed by the PSK:DATA table.
QPSK Discrete Selects the Quadrature Phase Shift Keying (QPSK)
modulation type. In this mode, the instrument
responds to 2 input bits that correspond to four
phases of the carrier wave. The symbols are shifts at
a rate determined by the PSK:BAUD command and
in a sequence as programmed by the PSK:DATA
table.
OQPSK Discrete Selects the Offset Phase Shift Keying (OPSK)
modulation type. The mapping is the same as for the
QPSK except the element of I is moved first and then
the element of Q is moved if the status changes from
one to another. These two steps are carried out
within the time of one step of QPSK. By shifting the
movement of the Q element, the status can be
changed without going through the origin even if a
change of 180

occurs. Because one symbol period
is calculated in two steps, an even value must be
used for oversampling. The symbols are shifts at a
rate determined by the PSK:BAUD command and in
a sequence as programmed by the PSK:DATA table.
DQPSK Discrete
Selects the

/4-shifted Differentially encoded QPSK
modulation type. In this mode, the symbol is located
at the position where the phase is shifted from the
current symbol position by 45

from the value of the
next data symbol. The first symbol position is defined
by QPSK. pre-defined values.

/4DQPSK uses both
the QPSK and another four-point table rotated by