Giga-tronics 8003, Operation Manual

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Operation
Manual 20791, Rev. C, June 2001 2-75
2.9 Insertion & Return Loss Measurements
This section defines how to configure your signal splitting components to make accurate insertion and
return loss measurements on a device or component. Depending on how you configure your
measurement accessories, you must DEFINE a channel path and choose how you will MEASURE your
device against stored calibration or trace data.
2.9.1 Single-Sensor Insertion Loss Measurement
The simplest insertion loss measurement consists of just measuring the power gain or loss at the output
of your Device Under Test (DUT).
In this simple measurement, first choose a channel to be the Insertion Loss channel. Then press the
[DEFINE]
key to bring up the
[DEFINE]
softkey menu. Select the [ SINGLE SENSOR ] softkey and
choose the sensor to be used for that channel (A, B, or C). The displayed trace now indicates true or
absolute power measured by the sensor.
An insertion loss measurement typically compares the ratio of the power out of the DUT to the power
into the DUT. In a single sensor measurement, this is normally done by first measuring the swept power
into the device and storing that result. This is called path calibration or path cal. This stored path cal is
then ratio’ed with the power measured out of the DUT. In the softkey menu, the selection [
MEASURE
ABS PWR/PTH CAL ] function determines whether the analyzer measures absolute power (ABS PWR)
or ratio’s the reading with the stored path (PTH CAL). The actual path calibration is done via the CAL
front panel key and the THRU softkey, with the sensor bypassing the DUT and connected directly to
the swept source, as shown in Figure 2-29.
Figure 2-29: Swept Source & Power Sensor Only Block Diagram (w/ DUT)