Specifications

Selbsttest ZVx
1043.0009.50 4.2 E-3
4.2 Monitoring the Function
4.2.1 Switch-on Test
After the instrument has been switched on, a self test of the processor functions is performed first. This
is followed by initialization of the transputer network, which then controls the analog modules.
4.2.2 Monitoring the Synthesizers and the Level Control
Note: The current firmware version doesn’t contain the error messages described below. If errors
occur in the syntesizers or in the level control, default values are set instead of the
respective measured values.
The network analyzer contains a monitoring circuit of the respective phase-locked loop for each
synthesizer and for the reference oscillator. Likewise, the phase-locked loop is monitored. Both the static
status and the dynamic response are monitored. If an error occurs, a message is output on the screen.
Table 4-1 Possible error messages
Message Meaning see section
REF UNLOCK 50-MHz reference oscillator not synchronized 4.2.3, Synthesizer Error Messages
SO UNLOCK Source oscillator not synchronized 4.2.3, Synthesizer Error Messages
LO1 UNLOCK First LO oscillator not synchronized 4.2.3, Synthesizer Error Messages
LO2 UNLOCK Second LO oscillator not synchronized 4.2.3, Synthesizer Error Messages
AUX UNLOCK Auxiliary oscillator not synchronized 4.2.3, Synthesizer Error Messages
LEVCTRL UNLOCK Generator level control not locked in 4.2.3, Synthesizer Error Messages
a1b1a2b2 OVLD Input signal in channel R1 (a1) and/or channel A
(b1) and/or channel R2 (a2, ZVR only and/or
channel B (b2) too large
4.2.5, Overload Displays
4.2.3 Synthesizer Error Messages
All phase-locked loops are monitored during operation in order to determine whether the tuning voltages
of the oscillators are within the permissible tolerance after a defined settling time (ready signals).
4.2.4 Error Message of Level Control
A check is made to determine whether the level control voltage lies within a permissible tolerance after a
defined period of time (level ready signal).
4.2.5 Overload Displays
A comparator is used on Converter A or Converter B, respectively, to determine whether the maximum
permissible test voltage is exceeded. A respective message is output either at the end of a sweep or,
with a sweep time > 5 s, immediately after the overload has occurred.