If you have a diagram or explanation of what your configuration looks like, it would help (including model numbers and options).
This error typically occurs when the reference is not receiving enough power to properly lock. For most analyzers, the R, R1, or R2 displays should show something above -30 dBm across the band. If you are using a PNA or PNA-L, try the below test (you can post the resulting screenshot if you like). If you are using a configurable test set (the semi rigid jumper beside the test ports) for this test have them in their default configuration.
Checking the receivers: 1. Disconnect everything from test ports (so that the ports are hanging open) 2. Preset the PNA 3. Go to: System->Service->Utilities->Receiver Display
" Anyone who can help me how can I repair or prevent this trouble for our Network Analyzer? "
You must tell us the model number, and firmeware revision. If it is an 8753, it is likely the trouble is not a good connection to the R channel, which is required.
Option 11 will show "phase locked lost" if you don't have a connection from the source out to the R channel. Typically this connection is made through the associated testset (85046, 85047). The ET and ES standard or option 6 should never show this message, if the R channel loop is connected. When you see this message it is typically because the source has gone bad (usually the YIG oscillator) or the R channel receiver has gone bad. You can sometimes get this message due to drift of the components over time, and the built in phase lock calibration factors are no longer correct for the current state of the hardware. There is a service test (don't remember the number just now) that will run to re-compute the phase lock calibration (phase lock service test). You can try this, but to get the numbers to "stick" I think you have to open the box and re-set the EEPROM write enable switch.
This error typically occurs when the reference is not receiving enough power to properly lock. For most analyzers, the R, R1, or R2 displays should show something above -30 dBm across the band. If you are using a PNA or PNA-L, try the below test (you can post the resulting screenshot if you like). If you are using a configurable test set (the semi rigid jumper beside the test ports) for this test have them in their default configuration.
Checking the receivers:
1. Disconnect everything from test ports (so that the ports are hanging open)
2. Preset the PNA
3. Go to: System->Service->Utilities->Receiver Display