Agilent Technologies 8935 series e6380a manual Time Offset

CDMA Measurements - Screens and Control Fields

CDMA Measurements

Time Offset

Time offset is displayed when the Rho measurement is selected. Time offset is the time difference between the base station’s even second and the start of the short sequence. It indicates how well your transmitter’s signal is time-aligned to system time. Time offset is measured at the base station’s antenna. The displayed value is based on the value entered in the PN Offset field. (See “PN Offset” on page 165.)

In Figure 5-2 on page 136 the first example is a measurement with a time offset of zero. The beginning of the received data block aligns with the first pilot PN chip of the reference signal. Zero time offset indicates that the trigger event to the CDMA Analyzer coincided with the arrival of the base station signal’s first pilot PN chip.

When the base station’s signal is delayed relative to the trigger event, time offset will be a positive value. The second example is a measurement with a positive time offset. The beginning of the data block will align with a portion of the reference signal toward the end of a pilot PN sequence. This indicates that the trigger event to the CDMA Analyzer occurred when the base station was still transmitting a pilot PN sequence prior to the first pilot PN chip of the expected sequence.

When the base station’s signal is early relative to the trigger event, time offset will be a negative value. The third example is a measurement with a negative time offset. The beginning of the data block will align with a portion of the reference signal after the first pilot PN chip. This indicates that the trigger event to the CDMA Analyzer occurred after arrival of the base station signal’s first pilot PN chip.

Screens on which this measurement is displayed

•CDMA ANALYZER

•CDMA GENERATOR

•CODE DOM (Code Domain Analyzer)

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