What should I do if a channel out of tolerance occurs during network analyzer maintenance?

A network analyzer is a new type of instrument for measuring network parameters. It can directly measure the complex scattering parameters of active or passive, reversible or irreversible two-port and single-port networks, and give the amplitude, phase and frequency characteristics of each scattering parameter in a frequency sweeping manner. Network analyzers are used very frequently in the RF field, and the price of an instrument is not cheap. The editor's annual salary is not as much as the price of a network analyzer.

Recently, Antai Testing and Maintenance Center received several network analyzers for repair, and two of them had channel out-of-tolerance failures. What should we do when such failures occur? How can we prevent them?

Fault phenomenon of network analyzer maintenance:

The transmission measurement in the power-on direct state is normal, and the single-channel measurement is 3-5dBm lower.

The return loss curve is abnormal.

The transmission test curve in the power-on direct-through state is in the shape of an inverted parabola.

Possible Causes:

It is very likely that the receiver components were broken down due to the intrusion of large signals or strong static electricity.

The protector of the signal input terminal may be burned out.

Precaution:

Perform a pre-test on the signal under test that is connected to the test end of the network analyzer.

Improve anti-static facilities and procedures.

According to the analysis of the network analyzer maintenance engineer of Antai Test and Maintenance Center, in addition to the channel out-of-tolerance fault, the following major faults are also very common faults that engineers encounter during maintenance:

1. Power failure: Cannot boot normally

2. Input fault: abnormal impedance; no signal; abnormal signal amplitude

3. Test and analysis failure: frequency and phase test abnormalities

4. Display failure: flower screen; black screen

5. Button failure: the button does not respond; the adjustment knob does not respond

6. Interface failure: storage medium is not recognized; cannot connect to the control system