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5.8.6 Modulation Phase
Pressing [Mod]>Phasesoftkey to set the modulation phase.
Use the numeric keypad or direction keys and knob to input the desired pahse values.
The phase range is from 0º to 360º and the default is 180º.
5.9 QPSK Modulation
Users can configure the instrument to "shift" its output phase between four preset values using
QPSK modulation. The rate at which the output shifts between the four phases (called the "carrier
phase" and three "modulation phases") is determined by the internal signal level of the instrument.
5.9.1 Select QPSK Modulation
Press [Mod] >Type > QPSKsoftkey to enable QPSK function.
When Mod is enabled, Sweep or Burst will be disabled automatically.
After QPSK is enabled, the instrument will generate QPSK waveform with the currently
specified carrier and modulating waveforms. To avoid multiple waveform changes, enable
modulation after configuring the other modulation parameters.
5.9.2 Carrier Waveform Shape
QPSK carrier shape: Sine (default), Square, Ramp, Pulse, Arbitrary (except DC) or Harmonic
waveform.
Press[Wave]button on the front panel to select the desired carrier waveform.
Noise and DC could not be used as carrier waveform.
5.9.3 Carrier WaveformPhase
Press[Setting] >Phasesoftkey on the front panel and use the numeric keypad or direction keys
and knob to input the desired phase.
The available phase ranges from 0º to 360º and the default value is 0º.
5.9.4 Modulation Source
QPSK uses the internal modulation source. After enabling QPSK modulation function, press
[Mod] >Data Source softkey, and select PN15 and PN21 codes as the modulation source. The
default is PN15 code.
User Manual 47
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