Graphical Access Probe Power Troubleshooting

Possible Setup Issues

If the Graphical Access Probe Power measurement is currently selected all other measurements are disabled.

The input signal must conform to Input Signal Requirements .

The graphical access probe power measurement becomes armed when the START SINGLE key is pressed or the INITiate GPIB command is sent. At that time, the test set calculates the number of expected access probes based on number of steps and maximum request or response sequence parameters.

If a registration occurs before a call is attempted, the measurement will disarm before the mobile station has finished sending access probes. This is because the test set does not distinguish between access probes occurring as a result of registrations, for example, and call attempts.

Graphical access probe power measurement results are affected by the Amplitude Offset value. Use the SYSTem:CORRection:GAIN command to determine offset values.

Graphical access probe power measurements are triggered by a rise in RF power that crosses approximately -55 dBm.

Clipping of Access Probes

The Graphical Access Probe Power measurement has a range of 15 dB. If the Power Step and Number of Steps are set up such that the mobile station transmits access probes greater than 15 dB from the first access probe, it will appear that the mobile station is transmitting a lower power level than expected.

To avoid this measurement inaccuracy, limit the Power Step and Number of Steps to yield no greater than 15 dB of change from the first (lowest power) access probe to the highest power access probe.

Interpreting Integrity Indicator values

See Integrity Indicator .

If over range (5) is returned the input power has exceeded the test set's internal sampler maximum value during some part of the sampling or the input power has exceeded the calibrated range of the test set's power detector.

If under range (6) is returned the measurement result is below the expected input power level. Under range is also indicated if the input power is below the calibrated range of the test set's power detector.

If the signal has both over range and under range conditions, only the over range (5) will be indicated.

Related Topics

Integrity Indicator

Graphical Access Probe Power Measurement Description