60
2)
External source
When using an external modulation source, the rate will not show in the parameter list, when an external waveform will be
used to modulate carrier waveform. PSK output phase is determined by logic level on external digital modulation interface
(FSK Trig connector). For example, when external input logic is low, carrier phase is output; when external input logic is
high, modulation phase is output.
Set PSK rate
The frequency between carrier phase and modulation phase can be set when using an internal modulation source. After
you use PSK function, you can set PSK rate, which is in the range of 2mHz~1MHz and 10kHz by default. You can change
it with multi-functional control and direction key on the interface for using PSK function or by pressing Rate.
Set modulation phase
Modulation phase is change in phase of waveform subject to PSK modulation relative to carrier phase. The range of PSK
modulation phase is 0º~360º, 180º by default. You can change it with the multi-functional control and direction keys on the
interface for using PSK function or by pressing Parameter Phase successively.
Comprehensive example
Set the instrument run in PSK mode, and then set an internal sine wave of 2kHz and 2Vpp as carrier signal. Finally set
frequency between carrier phase and modulation phase to be1kHz and phase to be 180º.
The specific steps are as follows:
1)
Use PSK function
Press MOD, Type and PSK in sequence (press soft key Type to select ) to use PSK function.
Figure 4- 59 Select PSK function
2)
Set carrier signal parameters
Press Sine to select carrier signal as a sine wave if previously set to another mode (Default carrier signal is a sine wave).
You can set with the multi-functional control and direction keys. You can also press the corresponding soft keys of function
again, when the interface below will display. To set some parameter, press corresponding soft key, input the required value
and select the unit.
