Fast Device Tune Troubleshooting

Possible Setup Issues

• The measurement is not performed with a call established between the test set and mobile station (MS). Rather, you must place your MS into a test mode which forces it to transmit a predefined series of power steps at various frequencies, and forces it to simultaneously tune its receiver to perform measurements of the test set's signal (to determine RSSI, for example) at various frequencies and power levels. Note that the test set does not report the mobile station's measurement results (for example, RSSI). You must capture the mobile station's measurement results so that you can compare its measurements with the test set's actual transmission levels.
• During front panel operation of this measurement, you must press the START SINGLE key to initiate the measurement.
• Ensure that you have met the Fast Device Tune Input Signal Requirements .
• Before performing a fast device tune measurement, ensure that the measurement has been properly calibrated (see Calibrating the Test Set ).
• The MS RX Power Sequence must include the same number of power steps as the MS TX Power Sequence, and the number of frequencies in the MS RX Frequency Sequence must match the number of frequency steps in the MS TX Frequency Sequence. If you do not want the MS to measure test set power at as many power levels or frequencies as you want the test set to measure from the MS, simply place "dummy" power levels or frequencies at the end of the MS RX Power Sequence and MS RX Frequency Sequence (for example, simply repeat the final power level or frequency). You can then ignore the mobile station's measurement results for these "dummy" points. Likewise, if you need more measurement points in the MS RX Frequency/Power Series than in the MS TX Frequency/Power Series, you can place "dummy" power levels and frequencies in the MS TX Frequency/Power Series, but note that the test set will still measure and report power for these "dummy" points. You must simply ignore these results.
• To ensure successful triggering of the measurement, follow the instructions at Triggering the Fast Device Tune Measurement .
• If you are running the measurement from the front panel, you must wait 2 seconds after initiating the measurement before instructing your mobile station to trigger the test set (if using the measurement remotely, you can use the INITiate:CFDTune:ARMed? query to determine that the measurement is ready; a separate wait statement is not required). To ensure that the test set triggered on the first transmission from the mobile, verify that the "Number of MS TX Power Steps Measured" returned by the FETCh:CFDTune[:ALL]? commands is equal to Number of Frequency Steps multiplied by Number of Power Steps .
• Required initial conditions:
  • Operating Mode must be set to IS-2000 Test .
  • Rcvr Power Ctrl must be set to Manual and Meas Frequency must be set to manual control (See Manual Receiver Control in IS-2000 Test Operating Mode ).
    To set Meas Frequency to manual control from the front panel, press the OFF/MANUAL key. This sets Meas Frequency to the last frequency value that this parameter was set to. The Fast Device Tune measurement ignores the specific value that Meas Frequency is set to, so it can be set to any supported input frequency; the measurement simply requires that Meas Frequency be in manual control mode
  • RF Gen Freq Ctrl must be set to Manual . See Manual Receiver Control in IS-2000 Test Operating Mode .
  • AWGN Power must be Off . If in the Lab Application , also make sure no external fading is applied (see Digital Bus Information ).
  • You must configure the MS TX Frequency/Power Series to match the pattern of power levels to be transmitted by the MS and configure the MS RX Frequency/Power Series to match the pattern of power levels to be measured by the MS (and at the appropriate frequencies). Ensure that you have included the frequency retune steps in your mobile station's transmit/receive sequences (for example, the number of power steps you've configured your mobile to transmit should be equal to the Number of Power Steps setting + 1).
  • Your mobile station should be configured to measure the test set's signal 5 ms after the start of each step, to allow the test set's source to settle.
• Ensure that you set the Measurement Timeout to a value great enough to allow you to command the MS to transmit its MS TX Frequency/Power Series and for the test set to measure the MS TX Frequency/Power Series. For example, measuring the maximum allowable number of 400 power points can take more than 10 seconds (400 steps plus the 19 re-tune steps: 419 x 20 ms = 8.4 seconds, plus ~ 2 seconds required for the measurement to prepare for triggering).
• MS TX Power Step Start Index + Number of Power Steps and MS RX Power Step Start Index + Number of Power Steps must not exceed 40.
• You must ensure that the range of power values selected by MS TX Power Step Start Index, MS RX Power Step Start Index and Number of Power Steps do not include any NANs (9.91E+37) or values that are outside of the input or output ranges for the current application format (considering the amplitude offset settings).
• MS TX Frequency Step Start Index + Number of Frequency Steps and MS RX Frequency Step Start Index + Number of Frequency Steps must not exceed 40.
• The frequencies indicated by MS TX Frequency Step Start Index and Number of Frequency Steps must be within one frequency band range. Likewise, the frequencies indicated by MS RX Frequency Step Start Index and Number of Frequency Steps must be within one frequency band range, but do not have to be in the same frequency band range as the MS TX Frequency Sequence. Ensure that none of the frequency values you've selected are NANs (9.91E+37)).
• Note that if you specify fewer than 40 values for the following commands: SETup:CFDTune:MS:RX:FREQuency:STEP[:VALues] , SETup:CFDTunee:MS:RX:POWer:STEP[:LEVels] , SETup:CFDTune:MS:TX:FREQuency:STEP[:VALues] and SETup:CFDTune:MS:TX:POWer:STEP[:LEVels] , the remaining values are set to NAN (9.91E+37).
• Although you can enter any power levels for MS TX Power Step Levels between -129 and +80 dBm (because this measurement is common to the W-CDMA/HSDPA, 1xEV-DO and cdma2000 formats), when running the Fast Device Tune measurement in the 1xEV-DO application/format, you can only measure power levels in the range of -79 to +30 dBm and the measurement is only specified for power levels in the range of -61 to +30 dBm (these ranges assume an amplitude offset of 0; the ranges change as you change amplitude offsets, see Amplitude Offset ).
• Although you can enter any frequencies for MS TX Frequency Step Values between 411 and 1980 MHz, when running the Fast Device Tune measurement in the 1xEV-DO application/format, you can only test frequencies within a single 1xEV-DO frequency band range:
  • 411 to 479 MHz (Band: NMT-450)
  • 806 to 924 MHz (Bands: US Cellular, Japan CDMA, China Cellular, and Secondary 800)
  • 1750 to 1780 MHz (Band: Korean PCS)
  • 1920 to 1980 MHz (Band: IMT-2000)
  • 1850 to 1915 (Bands: US PCS and US PCS 1900)
• Although you can enter any power levels for MS RX Power Step Levels between -165 and 37 dBm, when running the Fast Device Tune measurement in the cdma2000 application/format, the test set can only transmit test power levels in the range of -115 to -13 dBm (RF IN/OUT) or -115 to -5 dBm (RF OUT ONLY). These ranges assume an amplitude offset of 0; the allowable ranges change as you change amplitude offsets, see Cell Power, AWGN Power and Total RF Power Ranges .
• Although you can enter any frequencies for MS RX Frequency Step Values between 421 and 2170 MHz, when running the Fast Device Tune measurement in the cdma2000 application/format, you can only test frequencies within a single cdma2000 frequency band range:
  • 421 to 489 MHz (Band: NMT-450)
  • 800 to 960 MHz (Bands: US Cellular, Japan CDMA, China Cellular, and Secondary 800)
  • 1840 to 1870 MHz (Band: Korean PCS)
  • 2110 to 2170 MHz (Band: IMT-2000)
  • 1930 to 1995 (Bands: US PCS and US PCS 1900)

Other Considerations

• The Fast Device Tune measurement must re-range and re-trigger for every step in the MS TX Power Sequence. To ensure that this process is not interrupted by other operations, it is recommended that you not send any GPIB commands to the test set or press any front panel keys until the measurement has completed. If the measurement misses a trigger, it aborts and returns Integrity Indicator 30 : Missed Trigger .
• No other measurements can be running when a Fast Device Tune measurement is performed. If any measurements are running when a Fast Device Tune measurement is initiated, they are closed and a message is displayed to indicate that they were closed. Likewise, if any other measurements are initiated while a Fast Device Tune measurement is running, the Fast Device Tune measurement is closed and a message is displayed.
• Measurement results (and the RF generator output level) are affected by any RF IN/OUT Amplitude Offsets that are entered (see Amplitude Offset ).
• The Fast Device Tune measurement results are currently only available via GPIB command (see FETCh:CFDTune[:ALL]? ). Measurement results are not available on the front panel screen.

Related Topics

Fast Device Tune Measurement Description

Integrity Indicator