Справочник Пользователя для Rohde & Schwarz Inc SLV8000

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E-2

The basis for frequency generation is a 10 MHz oven-controlled crystal oscillator (OCXO).
This OCXO can be operated in different modes:

The OCXO runs in uncontrolled mode.

It obtains its control voltage via a D/A converter which can be set using the OCXO adjust
setting item. This allows the OCXO frequency applied at the test output 

 (

,

rear panel of the transmitter) to be adjusted to 10 MHz where necessary.

The OCXO runs in controlled mode.

Due to the control, the control voltage generated by the D/A converter is adapted on an on-
going basis so that the 10 MHz frequency of the OCXO is synchronized with the externally
supplied 5 MHz or 10 MHz reference frequency.

Mute on PPS Fail

Used to determine the behavior in SFN mode in the event of failure of 
the external time reference. The following settings are possible:

– off: The output signal is not suppressed

– only at startup: The output signal is suppressed at startup until a valid 

1 pps signal is detected; if the 1 pps signal fails after successful syn-
chronization, the output signal is no longer suppressed

– after fail delay time: The output signal is suppressed if the 1 pps sig-

nal fails for longer than the period specified under Fail Delay Time
This is the recommended setting for operation in SFN mode.

Mute on Ref. Fail

Used to determine the behavior in SFN and MFN mode in the event of 
failure of the external reference frequency source. The following settings 
are possible:

– off: The output signal is not suppressed

– only at startup: The output signal is suppressed at startup until a valid 

reference source is detected; if the reference source fails after suc-
cessful synchronization, the output signal is no longer suppressed

– after fail delay time: The output signal is suppressed if the reference 

source fails for longer than the period specified under Fail Delay Time
This is the recommended setting for operation in SFN mode.

Fail Delay Time

If a reference source fails, the time specified here must elapse before 
the output signal is suppressed. The setting is effective if "after fail delay 
time" is set under Mute on PPS Fail or Mute on Ref. Fail.

Selection: 0 to 24 hours; 0 hours = no delay time