Fast Device Tune Measurement Description

This section is only applicable to the lab application or feature-licensed test application.

Last updated: October 30, 2014

How is a Fast Device Tune Measurement Made?

The Fast Device Tune measurement allows you to simultaneously calibrate your mobile station's transmitter (TX) output power and receiver (RX) input level across level and frequency in a single sweep (per frequency band range). 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 CPICH RSCP, for example) at various frequencies and power levels.

Example MS TX and MS RX Frequency/Power Series for Fast Device Tune Measurement

Before initiating the measurement, you must specify the power sequence that the MS will transmit (MS TX Power Sequence), and the frequencies at which the MS will transmit the power sequence (MS TX Frequency Sequence). You must also specify the power sequence you want the test set to transmit (MS RX Power Sequence), and the frequencies at which you want the test set to transmit the power sequence (MS RX Frequency Sequence).

Configuring the MS TX Frequency/Power Series

The MS TX Power Sequence may include up to 40 steps (of 10 ms or 20 ms duration) that span some or all of the measurement's input range (the levels can step up or down with varying magnitudes of change, as long as the first step in the sequence provides a 20 dB rise to trigger the measurement). The MS TX Frequency Sequence may include up to 20 frequencies (within one frequency band range).

The test set can measure a total of 400 power points in one measurement cycle (for example: 20 power values at 20 different frequencies). However, the measurement allows you to enter up to 40 MS TX Power Step Levels and 40 MS TX Frequency Step Values (indexed from 0 to 39). You must then use the MS TX Power Step Start Index and Number of Power Steps settings to specify which power steps comprise the MS TX Power Sequence, and the MS TX Frequency Step Start Index and Number of Frequency Steps settings to specify which frequency steps comprise the MS TX Frequency Sequence. See Frequency/Power Series Example for an example illustrating how to utilize this flexibility.

The test set uses the values in the MS TX Power Sequence and the MS TX Frequency Sequence to build the MS TX Frequency/Power Series, which drives how the test set's receiver is tuned throughout the measurement cycle. To build the MS TX Frequency/Power Series, the test set simply repeats the MS TX Power Sequence at each of the frequencies in the MS TX Frequency Sequence, and inserts a frequency re-tune step in between each repetition of the power sequence (to allow the test set and MS to re-tune to the new frequency; no measurements are performed by the test set during the frequency re-tune steps). During the frequency re-tune steps, the test set tunes its receiver to the power and frequency values required for the first step in the next power sequence. The frequency re-tune steps are the same step length as the power sequence steps (10ms or 20 ms).

Before initiating the measurement, you must ensure that your MS is set to transmit the MS TX Frequency/Power Series you've set in the test set, including the frequency re-tune steps.

Configuring the MS RX Frequency/Power Series

While the test set is measuring the MS TX Power Sequence, it also transmits a MS RX Power Sequence for the MS to measure. This MS RX Power Sequence must include the same number of power steps as the MS TX Power Sequence (up to 40 steps of 10 ms or 20 ms duration). These steps can be at any power level in the test set's Cell Power output range.

The test set transmits its MS RX Power Sequence at each of the frequencies in the MS RX Frequency Sequence. The MS RX Frequency Sequence may include up to 20 frequencies within one frequency band range (which does not have to be the same frequency band range as the MS TX Frequency Sequence). 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.

As with the MS TX Frequency/Power Series, the test set can transmit a total of 400 power points in one measurement cycle (for example: 20 power values at 20 different frequencies), but the measurement allows you to enter up to 40 MS RX Power Step Levels and 40 MS RX Frequency Step Values (indexed from 0 to 39). You must then use the MS RX Power Step Start Index and Number of Power Steps settings to specify which power steps comprise the MS RX Power Sequence, and the MS RX Frequency Step Start Index and Number of Frequency Steps settings to specify which frequency steps comprise the MS RX Frequency Sequence. See Frequency/Power Series Example for an example illustrating how to utilize this flexibility.

As with the MS TX Frequency/Power Series, the test set uses the values in the MS RX Power Sequence and the MS RX Frequency Sequence to build the MS RX Frequency/Power Series, which drives how the test set's generator is tuned throughout the measurement cycle. To build the MS RX Frequency/Power Series, the test set simply repeats the MS RX Power Sequence at each of the frequencies in the MS RX Frequency Sequence, and inserts a frequency re-tune step in between each repetition of the power sequence (to allow the test set and MS to re-tune to the new frequency; the MS should not perform any measurements on the test set's signal during this time, or if a measurement is performed, you should ignore the measurement results). During the frequency re-tune steps, the test set moves its generator to the power and frequency values required for the first step in the next power sequence. The frequency re-tune steps are the same step length as the power sequence steps (10ms or 20 ms).

Before initiating the measurement, you must ensure that your MS is set to measure the MS RX Frequency/Power Series you've set in the test set, and that its tuning profile includes the frequency re-tune steps. 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.

To configure the downlink code channels transmitted by the test set during the MS RX Frequency/Power Series, see Downlink Channel Codes and Levels .

Frequency/Power Series Example

The test set can measure/transmit 400 power points in one measurement cycle. However, you can enter up to 40 power values and 40 frequencies for both the MS TX and MS RX sequences. This flexibility is present to make it more efficient for you to test different power sequences over different sets of frequencies or, more commonly, to test the same power sequence over different bands. You must load in the superset of power levels and frequency values once. Then for each measurement cycle, you simply change the start index and number of steps as needed and initiate the measurement.

For example, to measure a MS TX sequence of 14 power step levels in both the US Cellular and US PCS frequency bands:

and to transmit a MS RX sequence of 8 power step levels for the mobile station to measure:

for multiple US Cellular/US PCS mobile stations, set the following:

  2. MS TX Power Step Levels = 20, 16, 12, 8, 4, 0,-4, -8, -12, -16, -20, -30, -40, -50
    MS RX Power Step Levels = -90, -80, -70, -60, -50, -40, -30, -20, -75, -75, -75, -75, -75, -75 (note that the last six values are "dummy" values required so that there are an equal number of power steps in the MS TX and MS RX sequences)
    MS TX Frequency Step Values = 826.4, 830.4, 834.4, 838.4, 842.4, 846.4, 1852.4, 1856.4, 1860.4, 1864.4, 1870.4, 1874.4, 1878.4, 1882.4, 1886.4, 1890.4, 1894.4, 1898.4, 1902.4
    MS RX Frequency Step Values = 871.4, 875.4, 879.4, 883.4, 887.4, 891.4, 1932.4, 1936.4, 1940.1, 1944.4, 1950.4, 1954.4, 1958.4, 1962.4, 1966.4, 1970.4, 1974.4, 1978.4, 1982.4
  3. MS TX Power Step Start Index = 0
    MS RX Power Step Start Index = 0
    Number of Power Steps = 14
  4. Mobile station #1:
    • MS TX Frequency Step Start Index = 0
      MS RX Frequency Step Start Index = 0
      Number of Frequency Steps = 6
      Initiate the measurement, query INITiate:CFDTune:ARMed?, fetch the results
    • MS TX Frequency Step Start Index = 6
      MS RX Frequency Step Start Index = 6
      Number of Frequency Steps = 13
      Initiate the measurement, query INITiate:CFDTune:ARMed?, fetch the results
  5. Mobile station #2: repeat step 3
  6. Mobile station #3: repeat step 3
  7. ...

Triggering the Fast Device Tune Measurement

The MS must trigger the measurement with a positive change in power of at least 20 dB (the mobile station's power must rise from 20 dB below the level of the first step in the MS TX Power Sequence to within 9 dB of the level of the first step).

To ensure successful triggering, it is recommended that you do the following:

  2. Order the MS to transmit continuously at >20 dB below the power level of the first step in the MS TX Power Sequence.
    Note: If your MS TX Power Sequence starts at a power level that is less than 20 dB above the minimum transmit power of your MS, then you must include a trigger pulse as the first step in the MS TX Power Sequence. The power level of this trigger pulse will be measured by the test set as one of the steps in the sequence.
  3. Initiate the Fast Device Tune measurement (this prepares the test set's hardware to execute the frequency/power series you've specified and arms the measurement's RF rise trigger).
  4. Send the INITiate:CFDTune:ARMed? query and wait for it to return a value of 1 , indicating that the measurement is armed and ready to be triggered (or wait ~2 seconds if running the measurement from the front panel).
  5. Order the MS to begin transmission of its MS TX Frequency/Power Series (the MS should then increase its output power by more than 20 dB to reach the first step in the series, which triggers the measurement with an RF rise).

Once triggered, the Fast Device Tune measurement performs a series of channel power measurements, one near the center of each step of the MS TX Power Sequence (while simultaneously transmitting the MS RX Power Sequence you've specified), then repeats the measurements at the next specified MS TX frequency (while simultaneously transmitting the MS RX Power Sequence at the next specified MS RX frequency). The test set tunes its receiver for each step according to the power levels you've specified for the MS TX Power Sequence. The MS must step its power according to the MS TX Power Sequence (and be within +/- 9 dB of the expected power level for each step) and hold its power constant for the duration of the measurement interval (666.7 us, 6.3 ms after the start of each 20 ms step, or 3.15 ms after the start of each 10 ms step.). After completing a measurement at each step of the MS TX Frequency/Power Series, the measurement returns power results for all of the measured steps.

Required Initial Conditions

Operating 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 ).

Fast Device Tune Measurement Parameters

Fast Device Tune Setup

Fast Device Tune MS TX/RX Parameters

Fast Device Tune Measurement Results

The Fast Device Tune measurement results are currently only available via GPIB command (see FETCh:CFDTune ). Measurement results are not available on the front panel screen.

Note that the test set does not report the mobile station's measurement results (for example, CPICH RSCP). You must capture the mobile station's measurement results so that you can compare its measurements with the test set's actual transmission levels.

Fast Device Tune Input Signal Requirements

The Fast Device Tune measurement meets specifications when the following input signal requirements are met:

Calibrating the Fast Device Tune Measurement

You must calibrate this measurement using the Calibrate Measurements procedure (see Calibrating the Test Set ).

Related Topics

Programming a Fast Device Tune Measurement

How Do I Make a Fast Device Tune Measurement?

Fast Device Tune Troubleshooting

Channel Power Measurement Description

Receiver Control