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

Series 8500A Peak Power Meters
2.10 Dual Channel Measurements
Dual channel measurements are available only when using the Model 8502A power meter. The dual
channel capability of the Model 8502A provides two very useful functions. These are:
• Display of power measured by two channels simultaneously.
• Display of the power ratio between two channels.
Applications for these two functions are many and varied. Dual channel measurements allow two points
in a system to be measured with one power meter. The PPM can simultaneously measure both channels in
either the CW or Peak Power Modes.
The Ratio function allows relative measurements to be made in either CW or Peak. It is also possible to
ratio Peak to CW or CW to Peak. These functions are useful for gain and loss measurements under CW
or Peak conditions (or a combination of the two).
2.10.1 CW, CW Measurements
The following procedure is used for making dual channel CW measurements:
1. After power-on, press [CW] to access the CW Mode. Press [MEM] (3) [F1] for the PPM to use
its default values, if desired. Wait approximately 30 minutes for the PPM to warm up.
2. Self-Calibrate both channels. Press [MENU] (1) [F3] [F1].
3. Follow the instructions displayed by the PPM to connect the appropriate detector to the
Calibrator when prompted.
4. Connect the detectors to the device(s) or system to be tested.
5. The PPM will now be displaying the CW power for channel A. To display the CW power for
both channels, press [B].
6. Select the frequency of operation or cal factor as necessary for detector response correction by
pressing [FREQ].
7. Enter any required display offsets.
8. To return to single channel operation, use the Detector Select A and B keys as required.
2.10.2 Peak, Peak Measurements: Method 1
1. Follow the procedure given in Section 2.10.1, except press [PEAK] in Step 1 instead of CW.
2. If the PPM is triggering, it will display the peak power in both channels. The following default
settings are in effect if the PPM has been initialized.
a. Internal Trigger from channel A set at -10 dBm (i.e. pulse at channel A causes trigger if
greater than -10 dBm)
b. Frequency = 1.00 GHz
c. Chan A Cursor Delay = 1.0000 µs
d. Chan B Cursor Delay = 1.0000 µs
e. Spin knob active on channel A Cursor Delay as indicated by ∆ next to CSR DLY
3. If the PPM’s New Data and Ready lights are flashing, a trigger is occurring and measuring
should be possible. Try adjusting the channel A Cursor Delay by turning the spin knob until the
CSR DLY reads 0.0000 ns. The Delay can then be increased slowly until the reading is being
taken on the desired part of the pulse.
2-32 Manual No. 20790, Rev C, November 1998
Superceded by Revision D, March 2009