HP 8712ET User Manual page 72

Making Measurements
Measuring Transmission Response
View and Interpret the Transmission Measurement
Results.
1. To view the entire measurement trace on the display, press
Autoscale .
2. To interpret the transmission measurement, refer to
"Example of a Transmission Response Measurement Display,"
analyzer's display if you are making this measurement on your
instrument.
a. The values shown on the horizontal axis are the frequencies in
MHz. The values shown on the vertical axis are the power ratios
in decibels (dB) of the transmitted signal through the device
divided by the incident power. To display the result in logarithmic
magnitude format (designated by "Log Mag" at the top of the
measurement screen), the analyzer computes the measurement
trace using the following formula:
Transmission dB
where P = the power transmitted through the device and
trans
where P = the incident power.
inc
b. A level of 0 dB would indicate a lossless through cable or device
(no loss or gain). Values greater than 0 dB indicate that the DUT
has gain. Values less than 0 dB indicate loss.
3. To quickly determine the filter's minimum insertion loss, press
Marker Search
MARKER
4. Note the marker readout in
amplitude of the minimum insertion loss point.
3-20
P

( ) trans
------------- -
= 10 log

P
inc
Max Search
Figure 3-6
Figure 3-6,


−
Mkr > Max
provides the frequency and
ET User's Guide
SCALE
or your
.