Giga-tronics Series 12000A, Operation Manual

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Series 12000A Microwave Synthesizers
2-48 Publication 31231, Rev. J, October 2003
2.3.21 Internal Pulse Modulation (Series 12500A/12700A Only)
Press
[PM]
to select the modulation parameter. Refer to the modulation parameters and specifications
in Chapter 1 for detailed information.
When Option 24 is installed in the instrument, the Pulse Modulation screen appears as shown below. in
addition, the operation of the additional fields is described below.
Figure 2-29: Pulse Modulation Selection (Internal)
Trigger Source
This parameter selects either the rising or the falling edge of an external trigger as the start signal for each
pulse. When externally triggered, the internal generator will allow rates of 5 Hz to 5 MHz and will generate the
same widths and delays as in internal triggering.
Preference
This selection field allows two methods for pulse ‘timing’. If set to ‘Rate’, the repetition frequency for the pulse
group train (using the internal trigger) may be directly specified. There is no delay setting in this mode. When
this field is changed to ‘Start Delay’, the pulse repetition frequency is implicitly determined by the Delay and
Width parameters. Each of these methods can generate the same waveform if the parameters are set
appropriately. For example: setting a rate of 1 kHz with a width of 500 m s will produce the same waveform as
setting a start delay of 500 m s and a width of 500 m s (assuming a ‘singlet’ pulse selection). Note that this field
is always in the ‘Start Delay’ mode if the trigger selection is External.
Rate (Start Delay)
This field has two functions depending on the setting of the ‘Preference’ field (See above). When ‘Rate’ is
displayed, the repetition frequency for the pulse train may be entered directly. The internal pulse generator is
capable of generating pulse rates from 1 Hz to 3 MHz with widths of 100 ns to 1.67 seconds. When ‘Start
Delay’ is entered, the time from the trigger (internal or external) to the start of the first pulse in a group may be
entered. The delay (referenced to the Sync output) may be set from 0 to 1.67 seconds.
Width
This entry sets the width of each pulse produced, with either an external or an internal trigger. The width may
be set from 100 ns to 1.67 seconds. If the Waveform field is set to one of the multiple pulse selections, each
pulse in the group will have the same width.