Ceyear 3943B, Руководство по эксплуатации

Страница: 122 / 167

8 Technical indicators and testing methods
8.5 Performance characteristics test
114
other. Each frequency of the LO has a mirror frequency of corresponding input signal, with the difference
of two IFs between the signal and the mirror frequency. This test is to measure the ability of the
equipment to be tested to suppress the interference signal whose input frequency is its mirror frequency
rate.
b) Test diagram and test instruments and equipment
Synthetic Signal Generator1.................................... Recommend 1464/E8257D
Power Meters .............................................. Recommend AV2436/E4419
Power Probes ............................................ Recommend AV71710/9304A
Power Divider .............................................. Recommend 11667C
3.5mm(f)-N type(m) connector
Fig. 8.11 Schematic diagram of the test for mirror frequency suppression
c) Test procedure
1) Connect the test equipment as shown in Figure 8.11.
2) Reset the device to be tested. The device to be tested shares a common time base with the
synthesized signal generator, and the frequency reference of the device to be tested is set as the
external reference. Set the device to be tested to fixed frequency reception mode (FFM mode). In the IF
Panorama window, set the bandwidth to 100 kHz and the resolution bandwidth (RBW) to auto. Set the
center frequency and attenuator status according to auxiliary table B.11. Set the level unit to dBm. Set
the display maximum level according to the output power of the synthesized signal generator, so that the
maximum level is greater than the value by 3dB or more, and set the minimum level less than the
maximum level by 100dB.
3) Set the detection type to average, the measurement time mode to manual, and the measurement
time to 350ms.
4) Set the output frequency and power of the synthesized signal generator according to the auxiliary
table B.11, the frequency is the mirror frequency rate of the center frequency of the equipment to be
tested.
5) Use a power meter to measure the input power of the mirror frequency signal and record the value
in the auxiliary table B.11.
6) In the IF panoramic window of the device to be tested, the level value of the mirror frequency
interference signal is measured using the frequency scale and the value is recorded in the auxiliary table
B.11. If the mirror frequency interference signal level does not exceed the background noise by 10 dB,
the center frequency position level value is recorded in the auxiliary table B.11.