Giga-tronics 2508A, Operation Manual

Page: 59 / 132

Front Panel Operating Tasks
2500A Series Operation Manual, 34172 Revision C, March 2008
To modify the step size for the selected parameter, press the STEP SIZE button, enter a new step size
using the numeric keypad, then press any Units button.
2.4.3 Signal Generation
This section explains how to use the instrument to generate different types of output signals. CW, ramp
(sweep), and modulation modes are explained.
2.4.3.1 Generating a CW Signal
The following procedure explains how to set up the instrument to generate a continuous wave (CW) sig-
nal at a specified output power level. This procedure is also used to set up the carrier signal when modu-
lation is used.
The procedure follows:
1. Press the CW button to invoke the CW menu in the display.
2. Select the “Frequency” menu item in the CW menu, and enter the desired CW frequency using
either the numeric keypad, Step Up/Step Down buttons, or the rotary knob.
3. If the 90 dB step attenuator is installed in the unit, continue with the next step, otherwise, continue
with Step 4.
The step attenuator, if installed, can be set in either of two modes:
• Auto Mode - In this mode, the step attenuator automatically switches attenuation state as the
instrument’s output power level setting is varied. To set the step attenuator so that it automati-
cally switches attenuation levels with changes in output power level , press the SYSTEM button,
select the “System 1 Menu” menu item if it appears, select the “Attenuation” menu item, and
use the Step Down button to select Auto.
• Fixed Mode - In this mode, the step attenuator is set to a fixed level of attenuation. The maxi-
mum and minimum settable range is +25 dB to -20 dB relative to the attenuator setting. To set
the step attenuator so that it remains fixed at a desired level of attenuation , press the
SYSTEM button, select the “System 1 Menu” menu item if it appears, select the “Attenuation”
menu item, and use the Step Up or Step Down button to select the desired level of attenuation.
4. Return to the CW menu if necessary by pressing the CW button, select the “Power” menu item, and
enter the desired output power level. Using either the numeric keypad, Step Up/Step Down buttons,
or the rotary knob.
5. If you wish to use the instrument’s insertion/conversion loss compensation features, continue with
the next step, otherwise, continue with Step 8. The insertion/conversion loss compensation features
include the Power Offset feature, which is used to account for a fixed level of insertion or conversion
loss, and the Power Slope feature, which is used to account for insertion or conversion loss that lin-
early varies with frequency.