Giga-tronics 2508A, Operation Manual

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Front Panel Operating Tasks
2500A Series Operation Manual, 34172 Revision C, March 2008
the input polarity of the PULSE IN/PM TRIG IN signal is set to active high.
Figure 2-34: External Pulse Modulation
The procedure follows:
1. Perform steps 1 through 6 of the procedure entitled “Generating a CW Signal” to set the frequency
and power level of the carrier.
2. Connect a TTL pulse source to the PULSE IN/PM TRIG IN connector on the rear-panel of the
instrument, and set it for the desired modulating characteristics.
3. Press the PM button to invoke the PM Main menu, then press the PM Ext Menu.
4. Select the “PM” menu item in PM Menu 1, and use the Step Up or Step Down button or press the
adjacent soft key again to set it to On.
5. Select the “Input Polarity” menu item in PM Menu 1, and choose the appropriate polarity setting
using the Step Up/Step Down buttons.
With a setting of Active High, a TTL high level at the PULSE IN/PM TRIG IN connector turns on
the carrier at the RF output, and with a setting of Active Low, a TTL high level at the PULSE IN/PM
TRIG IN connector turns off the carrier at the RF output.
6. Select the “Sync Out Delay” menu item in PM Menu 1, and enter the desired sync pulse delay set-
ting using either the numeric keypad, Step Up/Step Down buttons, or the rotary knob.
7. If the LED indicator that is above the RF ON button is not lit, press the RF ON button to enable the
signal at the RF output connector.
When the signal at the RF output connector is enabled, the LED indicator that is above the RF ON
button is blue.
8. Verify that the Unleveled indicator is not lit.
Carrier
PULSE IN
RF Output