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External Source
When modulation source is external, carrier waveform will be modulated by an external waveform. PM phase
deviation is controlled by ±5V signal level of external modulation input terminal on front panel. For example, if phase
deviation value in parameter list has been set to 180º, +5V of external modulation signal is equivalent to 180º phase
shift.
Modulation Shape Frequency Setting
When modulation source is internal, frequency of modulation shape can be modulated. After enabling PM function,
the default of modulation shape frequency is 100Hz. If need to change, press Carrier Wave Parameter
→Modulation
Frequency in turn, and the modulation frequency range is 2mHz to 50kHz. When modulation source is external,
carrier waveform will be modulated by an external waveform. The range of modulation signal input from external is
0Hz to 20Hz.
Phase Deviation Setting
Phase deviation indicates the change between the phases of PM modulated waveform and the phase of carrier
wave phase. Settable range of PM phase deviation is from 0º to 360º, and the default value is 50º. If need to change,
press Parameter
→Phase Deviation in turn.
Comprehensive Example
Firstly, make the instrument work in phase modulation (PM) mode, then set a sine wave with 200Hz from the internal
of the instrument as a modulation signal and a square with frequency of 900Hz and amplitude of 100mVpp as a
carrier wave signal. Finally, set the phase deviation to 200º. Specific steps are seen as following:
1) Enable Phase Modulation (PM) Function
Press Menu
→Modulation→Type→Phase Modulation in turn to start the PM function.