114
Chapter 4
Performance Tests
2. Image Rejection Test
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2. Image Rejection Test
Description
The image rejection is checked at an LO power level of +15.2 dBm. A known input power is
applied to the input of the mixer. The IF output power is measured on an 8566B Spectrum
Analyzer at the input signal frequency and at the image response frequency. From the
measurements, the image rejection is determined. The image response appears on the
spectrum analyzer at a frequency of two times the IF frequency higher than the actual
signal frequency. In the case of the 8566B, the image response appears 642.8 MHz above
the actual frequency of the signal.
Procedure
1. Connect an SMA cable from the 1ST LO OUTPUT of the spectrum analyzer to the
INPUT of the 11975A Amplifier. Connect a second SMA cable to the OUTPUT of the
amplifier.
2. Connect the 8481A Power Sensor to the power meter sensor cable, then zero and
calibrate the 436A Power Meter.
3. Set the spectrum analyzer controls as follows:
SHIFT
⇑
⇑
⇑
⇑
(selects U Band)
FREQUENCY SPAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 Hz
CENTER FREQUENCY (sets LO frequency to 5.0 GHz) . . . . . . . . . 50.3 GHz
CAUTION
When you are using an 11975A Amplifier with an 11974, you must set the
amplifier rear-panel ALC switch to ON before you connect the amplifier to the
test setup. If the ALC switch is left in the OFF position, the amplifier output
power is high enough to destroy the mixer diodes.
4. On the 11975A Amplifier, set the rear-panel ALC switch to ON, then connect the 8481A
Power Sensor to the free end of the cable installed on the OUTPUT connector of the
amplifier. Set the 436A Power Meter Cal Factor % to the appropriate value for a
frequency of 5 GHz.
5. Adjust the amplifier OUTPUT POWER LEVEL for a reading of +15.2 dBm
±
0.1 dBm on
the power meter.
6. Connect the equipment as shown in
Summary of Contents for 11974 Series
Page 5: ...4 ...
Page 8: ...7 General Information 1 General Information ...
Page 28: ...27 Installation 2 Installation ...
Page 47: ...46 Chapter2 Installation Returning Equipment for Service Installation ...
Page 48: ...47 Operation 3 Operation ...
Page 97: ...96 Chapter3 Operation Using 8561A 62A 62B Spectrum Analyzers Operation ...
Page 98: ...97 Performance Tests 4 Performance Tests ...
Page 148: ...147 Safety and Regulatory Information 5 Safety and Regulatory Information ...