To provide the test engineer a guide in Calibrating the Hardware Test Fixture used on Cassini. This document will describe an example of how to perform a fixture calibration between ports RF5 and RF7 at low frequency. This example is usable when a fixture module is inserted into the signal path as well.
Example: Using RF5 to perform a low frequency ( 10MHz - 1010MHz) scalar calibration on RF7.
- The power vs frequency response at the end of a cable needs to be measured for RF5. A cable is attached to RF5 that is long enough to reach RF7 on the test head. A 10dB pad is attached to the cable closest to the power meter, in order to reduce any VSWR ripple that may occur. The power is set to -10dBm and is swept from 10MHz to 1010MHz as shown in the "RF5 Power Cal" pictures under the "Section Defaults" tab.
- The power response is measured and compared to the Source 1 power setting. This is then saved into a local variable "Input Power Using PM" and is sorted by frequency. This is shown in the "RF5 Power Cal Examples" under the "Test Panel" tab.
- The power meter is then removed and this end of the cable with the attenuator is attached to RF7.
- The power response is then measured between RF5 and RF7 and compared to the RF5 power response.
- The calibration data is then loaded into the cal factor "PathRF7DutRF1 and represents the loss of RF7. Please see pictures in "RF7 Loss Cal Examples" table.
RF5 Power Cal Examples:
This example can be used on any port to calibrate that port with an external Power Meter as the reference standard.
RF7 Loss Cal Examples:
This example can be used on RF port 2,3,6, or 7 to calibrate that port with an system receiver as the reference standard.