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Amplifier measurement example
Table 7. Absolute output power and 1 dB compression measurements of an amplifier
8510C Keystrokes
Description
Perform the flatness-correction calibration as presented in Table 1
Set up the test port power level
STIMULUS [MENU]
Set the test port power below the amplifier's compression level (P
{POWER MENU}
in Table 4.
{POWER SOURCE 1}
P
[x1]
A
Set up a b
measurement and connect a thru
2
PARAMETER [MENU]
Set up the analyzer for a b
{USER 2 b
}
2
Perform a thru calibration
[CAL]
Perform a thru calibration to eliminate the frequency response errors of the port 2 path in the measurement. Be sure to
{CAL#...}
include any attenuators and/or adapters which are part of the measurement in the thru calibration. It may be necessary
{CALIBRATE:RESPONSE}
to swap adapters for the thru calibration. Any cal set may be selected to access the response calibration in the calibration
{THRU}
menu structure.
{DONE RESPONSE}
{CAL SET #}
Connect the amplifier and measure the absolute output power
RESPONSE [MENU]
Display the absolute power by entering a magnitude offset (P
{MORE}
calibration. Gain can be calculated for any measurement point by subtracting P
{MAGNITUDE OFFSET}
can also be measured by performing an S
P
[x1]
A
[AUTO]
Set up a 1 dB compression measurement and normalize the trace
[DISPLAY]
By normalizing the measurement, the first frequency point to drop by 1 dB will be easy to identify.
{DATA AND MEMORIES}
{DISPLAY→ MEMORY 1}
{MATH(/)}
Adjust the display
[REF VALUE]
Move the reference line near the bottom of the grid to allow full use of the display.
1 [x1]
[REF POSN]
USE DOWN ARROW
[SCALE]
1 [x1]
Increase power to find the 1 dB gain compression point
STIMULUS [MENU]
Increase the test port power 1 dB at a time until the trace visibly drops. Then use the knob to adjust the power until
{POWER MENU}
a 1 dB drop in the trace occurs. Note the test port power and use a marker to measure the frequency.
{POWER SOURCE 1}
USE UP ARROW
[MARKER]
Measure the absolute output power at the 1 dB compression point
[REF POSN]
Move the reference level back to the center of the screen and display the absolute output power versus frequency.
[DISPLAY]
The marker will indicate the amplifier's absolute output power for the1 dB compression point.
{DATA AND MEMORIES}
{DISPLAY:DATA}
[AUTO]
measurement.
2
measurement.
21
) and within the settable power range presented
A
) equivalent to the test port power level during the thru
A
from P
(or P
in
out
/P
). The gain
measured
A
11
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