Ceyear 4051 Series, Руководство пользователя

Страница: 685 / 751

8. Specifications and test methods
8.5 Performance characteristics test
671
Where, ΔA
500
refers to the 500 MHz absolute amplitude accuracy (dB);
ΔA
P
refers to the frequency response data obtained from the test in 4.6.12.2.3 (dB).
8.5.1.2.6 Input voltage standing-wave ratio
a) Test items
Impedance mismatch will lead to production of reflected voltage. The incident voltage and the reflected
voltage transmit in two opposite directions to produce certain interference pattern. The standing-wave ratio is
the ratio of the maximum value against the minimum value of the voltage pattern envelop.
The standing-wave test function of the vector network analyzer can be directly used to test the input voltage
standing-wave ratio at the input interface of the signal/spectrum analyzer.
b) Testing block diagram and testing instrument and equipment
N5247A is recommended for the network analyzer.
Fig. 8.12 Schematic diagram of input interface voltage standing-wave ratio test
c) Test steps
1) Reset the 4051 analyzer and check to confirm the input attenuator is set as 10 dB.
2) Set the frequency range and the source output power of the network analyzer properly and select VSWR
display mode.
3) Select calibration cable for the network analyzer for single-interface measurement and calibration
(including open circuit, short circuit and load calibration).
4) After calibration, take the calibrated part from the calibration cable and connect the test cable interface to
the output interface of the 4051 analyzer as shown in Fig. 8.11.
5) Use the marker function to read out the VSWR of corresponding band of the 4051 analyzer in the network
analyzer.
d) Test records and data processing
6) Record measurement results in the 4051 Record Sheet.
8.5.1.2.7 Resolution bandwidth switching error
a) Test items
The resolution bandwidth is affected by configured parameters during switching, resulting in gain error. Such
error has been modified during instrument design, however, certain amplitude error still exists due to
calibration methods and environmental change.