Manual - 8500A Series Peak Power Meter - Giga-tronics

Operation
Figure 2-6. Typical Single Channel Peak Power Display
2. Press [FREQ] and enter either the RF operating frequency or the Cal Factor in dB. (This step is
not required if the External Frequency input mode is being used.)
3. Enter any required offset as described in Section 2.8.3.
4. If desired, the Peak Averaging can be changed by pressing [MENU] (2) [F2] [nnn] [Units].
(nnn = number of samples to be averaged - must be between 1 and 999. Default is 4)
5. The power will then appear on the display.
6. To change the time at which the power readings are taken, adjust the spin knob on the front panel.
Alternatively, Delay entries can also be made through the keypad. After the desired numeric
entry has been made, pressing the appropriate Units key will enter the delay in either
nanoseconds, microseconds, or milliseconds. Pressing any UNITS key without entering any
numbers will cause the cursor symbol (∆) next to the DLY indication on the screen ( CSR DLY =
N.NN ns) to disappear. This indicates that the keypad and spin knob are inactive and keeps the
spin knob from being accidentally bumped and moving the cursor to some undesired delay time.
To reactivate the Delay time entry, press either the up or down arrow key.
Method 2: Peak Mode - Direct Access
For the purposes of this procedure, assume that either the single channel 8501A or only channel A of the
dual channel 8502A is being used. The procedures for channel B of the 8502A are almost the same as
those for channel A. However, if it is desired to use the Internal Trigger function with channel B, this
must be selected by using the MENU key as described under Internal Triggering in Section 2.6.2.
1. Allow the PPM to warm up for 30 minutes, then conduct the Self Calibration procedure (see
Section 2.5).
2. Select the Peak Power Mode of operation. Observe the triggering guidelines. If there is no
external trigger available or if there is any uncertainty as to which method to use, use the
Internal Trigger (see Section 2.6.2).
3. To verify that the PPM is in the desired mode and that it is receiving the proper triggering, check
the following:
a. The light in the center of the PEAK key should be lit. (If not, this means that the Peak Mode
has not been entered.)
b. The Ready and New Data lights should be flashing. (If not, then the system is not receiving
a trigger. If external was selected and no triggering indication is observed, try the Internal
Trigger function. The RF pulse power level must be greater than -10 dBm.)
4. Once Step 3 has been successfully accomplished, the PPM should be taking readings in the Peak
Power Mode. However, the cursor might not be positioned on the specific pulse of interest at this
Manual No. 20790, Rev C, November 1998 2-21
Superceded by Revision D, March 2009