RFmx WCDMA 19.1 Help
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The primary objective of the SlotPhase measurement is to obtain the phase discontinuity at each slot boundary.
SlotPhase measurement is also useful to obtain the phase of the corrected received signal with respect to an ideal signal. This phase information is obtained for all the chips within the measurement interval.
According to the 3GPP standard, phase discontinuity result is the change in phase between adjacent timeslots. Phase discontinuity is obtained as follows:
- The received signal is corrected for frequency, absolute phase, absolute amplitude, and chip clock timing based on the ideal signal.
- The transient period of 25 microseconds is removed from the start and end of the slot, and a linear fit of the phase of the corrected signal is obtained for the slot.
- This linear fit of the phase is extrapolated to the slot boundaries. The slope of this linear fit indicates the frequency error.
- The same steps are repeated for all the slots. The difference between the first extrapolated chip phase of the current slot and the last extrapolated chip phase of the preceding slot is measured as the phase discontinuity. There is a provision to disable the removal of the transient period, if required, for signals which do not have a power change between slots.
The key result of SlotPhase measurement is the array of phase discontinuity values for all slot boundaries within the selected measurement interval. Apart from this, the measurement returns results corresponding to the Maximum Phase Discontinuity, Discontinuity Count > 36 degrees , Discontinuity Count > 66 degrees, and Minimum Distance between Discontinuities > 36 degrees.
The measurement allows us to view the traces for chip phase error and chip phase error linear fit.
The WCDMA SlotPhase measurement supports the following channel configuration modes:
- Set the Channel Configuration Mode property to Auto Detect, so the measurement detects the transmitted channels. This value is the default.
- Set the Channel Configuration Mode property to Test Model, and set the UL Test Model property to use a predefined test model.
- Set the Channel Configuration Mode property to User Defined to use a custom channel configuration.
The WCDMA SlotPhase synchronization modes enable you to synchronize to the frame or slot boundaries. It allows you to measure specific slots in a frame, where as the slot mode starts the measurement from the first complete slot in the acquisition.
RFmx WCDMA supports the following synchronization modes:
- Slot synchronization mode—Allows you to make SlotPhase measurements over the configured number of slots, starting at the configured offset from the first complete slot in the acquisition.
- Frame synchronization mode—Allows you to make SlotPhase measurements over the configured number of slots, starting at the configured offset from the first complete frame in the acquisition. This mode allows you to measure specific slots in a frame.
The WCDMA SlotPhase measurement allows multi-frame measurement.