Interpreting the Display
The GSM/EDGE Tx Analyzer screen is divided into two sections in the Channel Scanner and the Spectrum views, and into three sections in the Power versus Time view:
In the Power versus Time view only, the third section displayed is of slot information. This is the row of power values at the top of the screen
- The graphics display, that is, the graphic chart taking up most of the upper part of the screen
- The metrics display, that is, the table of values at the bottom of the screen
NOTE The results metrics that are displayed will not correlate precisely with the plot that you see. This is because the analyzer performs two or more separate data acquisitions - at least one to gather the data for the graphical plot, and a separate acquisition to display data for the metrics. Any small variances between the two displayed results are due to variances in the signal over time.
The Graphics Display contains the graphical view of your measurement. You can change this view by pressing [Display] and [View], and then selecting one of the three view options available to you. The three views are:
Channel Scanner: The graphics display shows channel power. In this display, the power of each selected channel is shown. The Y-axis labels display the absolute power (dBm), and dB/division. The X-axis labels display the frequency or channel number. Channel Scanner in GSM Tx Analyzer and in EDGE Tx Analyzer both use the 'Peak Detector' and therefore the displayed bar height is the 'Peak power in the acquisition'.
Power vs. Time with Zoom set to "Slots": The graphics display shows power versus time for the channel selected using [Display], then [Position]. In this display, the power of the channel (or of part of the channel) you selected is shown against time. The Y-axis labels display the absolute power (dBm), and dB/division. The X-axis represents time, and shows from 60 ms before the first of your specified timeslots, up to 60 ms after the last of your specified timeslots.
NOTE It is worth noting that regardless of which slot you have displayed in the graphics portion of the screen, the displayed metrics always refer to the first slot, that is, to Slot 0.
- You can display one or more of the eight slots in the channel of interest. The number of slots displayed is determined by your Zoom Interval setting. For more details, see "Setting Zoom Interval"
- The left-most slot displayed is determined by your Zoom Offset setting. For more details, see "Setting Zoom Offset"
Power vs. Time with Zoom set to "Rise/Fall": The graphics display shows power versus time for part of the selected slot ([Zoom Offset]) in the selected channel ([Display], then [Position]). The power of the slot you selected is shown against time.
- If the Power versus Time mask is set to On, you will also see a mask indicating the lower and the upper limits for the channels you are displaying. The lower limit mask is displayed in yellow, and the upper limit mask in magenta (pink). The green signal trace must lie between these limits for it to pass the Mask Test. For more details on the PvT mask, see "Setting PvT Mask"
- The power in each slot is displayed at the top of the screen, together with the results of the mask test for each slot. A 'P' in a green circle represents a Pass, and an 'F' in a red triangle represents a Fail. Each red triangle has an arrow beside it that indicates whether it is the upper limit, the lower limit, or both limits that have failed. A double-ended arrow indicates both upper and lower limits failed, an arrow pointing up indicates an upper limit failure, and an arrow pointing down indicates a lower limit failure. The entire channel's Pass or Fail status is also displayed.
NOTE It is worth noting that regardless of which slot you have displayed in the graphics portion of the screen, the displayed metrics always refer to the first slot, that is, to Slot 0.
- The Y-axis labels display the absolute power (dBm), and dB/division. The X-axis represents time. The portion of the X-axis to the left of the gray bar represents from 60 ms before the start, to 60 ms after the start, of the slot of interest.
- The gray bar in the center of the display represents the central portion of the slot for which no data is displayed.
- The portion of the X-axis to the right of the gray bar represents from 60 ms before the end, to 60 ms after the end, of the slot of interest. The power values ("TS Pwr") at the top of the screen represent the maximum TS Power for each of the eight slots in the frame.
- The slot whose trace is displayed is determined by your Zoom Offset setting. For more details, see "Setting Zoom Offset"
Spectrum: The graphics display shows spectral power for the selected slot ([Slot Sync]) in the selected channel ([Display], then [Position]) measured in a 500 kHz acquisition bandwidth. The Y-axis labels display the absolute power (dBm), and dB/division. The X-axis represents frequency, and shows the frequency across the Channel selected with your [Position] setting.
- If the Power versus Time mask is set to On, you will also see a mask indicating the lower and the upper limits for the channels you are displaying. The lower limit mask is displayed in yellow, and the upper limit mask in magenta (pink). The green signal trace must lie between these limits for it to pass the Mask Test. For more details on the PvT mask, see "Setting PvT Mask"
- The power in each slot is displayed at the top of the screen, together with the results of the mask test for each slot. A green 'P' represents a Pass, and a red 'F' represents a Fail. The entire channel's Pass or Fail status is also displayed.
The metrics display shows measurement parameters displayed below the trace display in three columns and five rows-each with a value and units (the exceptions are BSIC, TSC, and Mod Type, which have no units.) For more information about the parameters in the metric display, refer to "Metrics Provided by the GSM and EDGE Analyzer Measurement"
The frequency reference indicator is at the bottom right, and the time reference indicator at the bottom left. For each indicator the text indicates which reference you have chosen. A green LED indicates a locked condition, a red "X," an unlocked condition.