How Do I Make an Output RF Spectrum Measurement?

How Do I Make an Output RF Spectrum Measurement?

Last updated: December 2, 2008

Measuring 3GPP TS 13.16.3 / 13.16.4 Output RF Spectrum

This procedure assumes that the BCH parameter for Cell Band is set up correctly for your mobile station and that the appropriate RF IN/OUT Amplitude Offsets have been set to offset loss between the mobile station and the test set. For more details see How Do I Configure the Test Set for My Test System? .

  1. Connect the mobile.

  2. Turn the mobile on and wait for Attached in the Active Cell field.
    Note: For mobiles that don't perform a GPRS attach automatically, set the mobile to data mode.

  3. Press the Start Data Connection ( F3 ) key and watch for the Active Cell field changing to Transferring .
  4. Press the Measurement selection key.
  5. Select the Output RF Spectrum measurement.
  6. Press the ORFS Setup ( F1 ) key.
  7. Press the Measurement Setup ( F1 ) key.
  8. Set the measurement parameters as needed for your measurement, including:
    Measurement Timeout = 20 s.
  9. Press the Modulation Frequencies ( F2 ) key and set up your required offset frequencies for ORFS due to modulation.
  10. Press the Close Menu ( F6 ) key.
  11. Press the Switching Frequencies ( F3 ) key and set up your required offset frequencies for ORFS due to switching.
  12. Press the Close Menu ( F6 ) key.
  13. Press the Return ( F6 ) key.
  14. Press the Change View ( F2 ) key.
  15. Press the Modulation Numeric ( F1 ) key.

    The figure above displays the ORFS measurement results. Note that the results are in dB relative to the 30 kHz BW Power shown on the screen.
  16. Press the Switching Numeric ( F2 ) key to display the measurement results for ORFS due to switching.

    A typical measurement results screen for ORFS due to switching is shown above.

  17. Press the Graph ( F3 ) key then the Modulation ( F1 ) key to access the ORFS due to modulation bar graph.

    A typical ORFS due to modulation graph is shown above. On the display, the bar representing each offset is shown in yellow and the center frequency is indicated by a white vertical line. There are two limit lines displayed; the absolute limit line is green and the relative limit line is blue. The pass/fail result is relevant to the displayed measurement.

  18. Press the Switching ( F2 ) key to access the ORFS due to switching bar graph.

    A typical ORFS due to switching graph is shown above. On the display, the bar representing each offset is shown in blue and the center frequency is indicated by a white vertical line.

    In this case, the marker is turned on and positioned at the 600 kHz offset. The signal level and frequency of the offset where the marker is positioned, are shown at the top of the display above the graph.

    The marker can be turned on by pressing the Graph Control ( F5 ) key then the Marker Position ( F2 ) key. Set the required marker position using the knob or the numeric entry keys. In addition, the axis values can be changed by pressing the Axis Control ( F1 ) key. This allows you to zoom in or out to look at particular sections of the graph in more detail.

  19. Press the Modulation and Switching ( F3 ) key to access a screen displaying both graphs, as shown in the example below.

    Note that each of the graphs have their own graph controls on F4 and F5 .

    Any failing results are displayed in red.

    If you require details on how to navigate through the Output RF Spectrum graph menus, see Output RF Spectrum Graph Menus .

  20. Press the More key then the Switching Time Domain ( F1 ) key to access a screen displaying Switching Time Domain Graph, as shown in the example below:

    A typical ORFS due to switching Time Domain graph is shown above. On the display, the X axis shows the time of the burst trace data, and the Y axis shows the power value of the burst trace data. A vertical pink line is placed in the middle of bit 0 (or symbol 0 for 8PSK) of each burst. The center position of bit 0 of the burst that you have selected to measure is referred to as 0 us. The start and stop time of the trace data is displayed below the graph. A Marker can be turned on and scrolled across trace data. In this case, the marker is turned on and positioned at the 492.407 us. The signal level and time of the offset where the marker is positioned are shown at the top of the display above the graph.

    Note, the highest level of the Switching ORFS Time Domain trace may not be exactly the same as the result displayed in the Switching ORFS Numeric result screen, since the sampling rate for these two results are different.

  21. Verify the results from the test set meet the conformance requirements detailed in 3GPP TS 51.010 (Version 5.9) section 13.16.3.2 for GPRS mobile stations and 13.17.4.2 for EGPRS mobile stations.

Output RF Spectrum Graph Menus

Related Topics

Output RF Spectrum Measurement Description

Programming an Output RF Spectrum Measurement

ORFS Troubleshooting