Tabor Electronics 5064, User Manual

Page: 271 / 369

5-50
QAM Modulation
Programming
Use the following command for programming the QAM parameters.
The QAM commands allow selection of the (n)QAM type,
programming the QAM baud, placing the marker position, turning
the carrier waveform (CW) on and off function and designing data
symbols.
QAM:TYPE{16QAM|64QAM|256QAM|USER}(?)
Description
This selects between the various (n)QAM modulation schemes. The 16QAM, 64QAM and 256QAM types
have standard symbol configuration. In case you need non-standard symbol constellations, use the User
QAM to design your own symbol data.
Parameters
Name Type Default Description
16QAM Discrete 16QAM Selects the 16 Quadrature Amplitude Modulation
(16QAM) modulation type. 16QAM is a 4-level
modulation method that uses 16 phases/amplitude
symbols. The first two bits define at which event of
the IQ plane the phase exists (00: upper right, 01:
upper left, 10: lower left, 11: lower right) and the rest
of the 2 bits defines the position of the symbol in each
event.
The instrument steps through these events in a
sequence as listed in the QAM:DATA table and at a
frequency
which is programmed using the
QAM:BAUD parameter.
64QAM Discrete Selects the 64 Quadrature Amplitude Modulation
(64QAM) modulation type. 64QAM is a 6-level
modulation method that uses 64 phases/amplitude
symbols. The first two bits define at which event of
the IQ plane the phase exists (00: upper right, 01:
upper left, 10: lower left, 11: lower right) and the rest
of the 4 bits defines the position of the symbol in each
event.
The instrument steps through these events in a
sequence as listed in the QAM:DATA table and at a
frequency
which is programmed using the
QAM:BAUD parameter.
256QAM Discrete Selects the 256 Quadrature Amplitude Modulation
(256QAM) modulation type. 64QAM is a 8-level
modulation method that uses 256 phases/amplitude
symbols. The first two bits define at which event of
the IQ plane the phase exists (00: upper right, 01:
upper left, 10: lower left, 11: lower right) and the rest
of the 6 bits defines the position of the symbol in each
event.