JDS Uniphase CellAdvisor JD780A Series, User Manual

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JD780A Series Analyzers
Using WCDMA/HSPA+ Signal Analyzer
159
Procedure
1.
Press the TRIGGER hot key.
2.
Select the trigger source option from the following choices: Internal , External , or GPS .
Setting external clock
To enhance the reliability of modulation analysis measurements the JD780A series must be
synchronized with a base station. When an external clock is not supplied, the instrument works with its
built-in internal high-accuracy time base and some measurement results may exhibit inaccurate values.
Therefore, it is highly recommended that you use the same reference clock as the signal source. You
can use the
TRIGGER hot key to set the external clock.
Table 12 Standards of external clock operation
Clock Type Reference Port Switching Standard
External
Reference Internal Internal 10 MHz Default
External External Ref Clock Ext Ref (SMA) Manual switching
(Input signal level >-3 dBm)
GPS GPS Clock GPS (SMA) Automatic switching
(GPS signal received)
Trigger Internal Internal Trigger Default
External External Trigger Trigger (SMA) Manual switching
GPS GPS GPS (SMA) Manual switching
Figure 56 Connection ports for external reference clock
Procedure
1.
Connect an external reference or a GPS antenna to the JD780A series.
2.
Press the SYSTEM hot key.
3.
Press the Freq Reference soft key, and then select the reference option: Internal , External 10
MHz , External 13 MHz , External 15 MHz , or GPS .
NOTE
When a GPS antenna is connected and locked, GPS coordinates (longitude and latitude)
are displayed on the screen and frequency reference is automatically set to GPS in the
System > Freq Reference .