Neighbour Cell Synchronization Trigger

Last updated: December 3, 2008

The neighbour cell synchronization trigger is useful for synchronizing other network simulating equipment to the test set for E-OTD testing. See E-OTD (Enhanced Observed Time Difference) for more information.

This trigger is provided at the rear panel TRIG OUT connector.

Trigger Control

Control of the synchronization trigger is available only by using a GPIB command. There is one configurable parameter which allows you to determine when the trigger is fired. See CALL:TRIGger[:OUTPut]:FRAMe:SYNChronize:OFFSet .

Trigger Timing

After the test set receives the GPIB command to generate the synchronization trigger, the test set's frame count is set to 2715448. This frame occurs 200 frames before the end of the hyperframe. When the trigger is generated depends on the offset you have specified. If no offset is defined, the trigger is generated when the first symbol of the next hyperframe occurs which is when the frame count becomes 0. Otherwise, the trigger is generated before the first symbol of the next hyperframe by the number of symbols specified in the offset.

Operating Considerations

Operating Mode

You can use the synchronization trigger in the following operating modes:

Active Cell
GSM BCH
GPRS BCH
GSM BCH + TCH
GPRS BCH + PDTCH

Interaction with other triggers

It is important to ensure that the other triggers provided by the test set are disabled before sending the synchronization trigger. An additional signal at the trigger output interferes with the synchronization process.

Use the CALL:TRIGger[:OUTPut][:ALL]:STATe:OFF to disable all triggers before sending the synchronization trigger command.