HP ESA-L1500A, User'S And Calibration Manual

Page: 261 / 326

260 Chapter 9
Performance Verification Tests
15. Gain Compression
15. Gain Compression
Gain compression is measured by applying two signals, separated by
3 MHz. First, the test places a
−
26 dBm signal at the input of the
spectrum analyzer (the spectrum analyzer reference level is set to
−
10 dBm). Then, a 0 dBm signal (46.75 dBmV for 75
Ω
) is applied to the
spectrum analyzer, overdriving its input. The decrease in the first
signal’s amplitude (gain compression) caused by the second signal is the
measured gain compression.
There are no related adjustment procedures for this performance test.
Equipment Required
Synthesized sweeper
Synthesized signal generator
Measuring receiver (used as a power meter)
Power sensor, 100 kHz to 1500 MHz
Directional bridge
Cable, BNC, 120-cm (48-in) (2 required)
Adapter, Type-N (f) to BNC (m)
Adapter, Type-N (m) to BNC (m)
Adapter, Type-N (f) to APC 3.5 (f)
Adapter, Type-N (m) to BNC (f) (2 required)
Additional Equipment for 75
Ω
Input
Power sensor, 75
Ω
Adapter, Type-N (f), to BNC (m), 75
Ω
Adapter, BNC (m), to BNC (m), 75
Ω
Procedure
1. Zero and calibrate the measuring receiver and 100 kHz to 1500 MHz
power sensor combination in log mode (power reads out in dBm) as
described in the measuring receiver operation manual. Enter the
power sensor’s 50 MHz Cal Factor into the measuring receiver.
75
Ω
Input only: Calibrate the 75
Ω
power sensor.
2. Connect the equipment as shown in Figure 9-17 , with the load port
of the directional bridge connected to the power sensor.