Handoff waveform quality measurements test a transmitter's modulation accuracy during transmission of a single code channel, the reverse Pilot Channel. The handoff involves changing the current PN (pseudo-noise) offset to force the mobile station to transmit a preamble on the Pilot Channel only. Reverse link power control is changed to alternating up/down bits and waveform quality is measured. After the measurement, the PN offset is returned to the original setting and the power control is returned to the original setting.
Each handoff waveform quality measurement returns a number of measurements which include rho, the percentage of signal energy that correlates with a perfect IS-2000 signal after time offset and frequency error have been removed.
This measurement is designed to analyze signals that are made up of multiple code channels, as in the case of radio configurations three and above.
Waveform quality measurements are made by sampling the down-converted input signal, then applying DSP (Digital Signal Processing) techniques to determine the original data input to the mobile station transmitter's Walsh spreading function for each channel. The DSP then generates a representation of what the "ideal" signal would be given the coding and data in use at the time of transmission. The ideal waveform is then compared with the waveform being measured to determine the waveform quality.
Handoff Waveform Quality measurement results lists the Handoff Waveform Quality measurements:
Handoff Waveform Quality |
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Rho |
Frequency Error |
Timing Error |
Carrier Feedthrough |
Phase Error |
Magnitude Error |
The handoff waveform quality measurement does not provide the Multi-Measurement Count feature in the setup menu.
Handoff waveform quality measurements are always triggered singly (press the START SINGLE key to initiate a measurement from the front panel).
The handoff waveform quality measurement meets or exceeds specifications when the following input signal requirements are met:
The handoff waveform quality measurement is automatically calibrated during a channel power calibration. Follow the channel power calibration schedule and the handoff waveform quality measurement will be properly calibrated. Refer to Calibrating the Test Set for a description of channel power calibration.
Measuring Handoff Waveform Quality
Programming a Handoff Waveform Quality Measurement