Tektronix 2715, Руководство пользователя

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Spectrum Analyzer Menus
2715 User Manual
6–41
3. Press [2] [ ] [2] [Z] to enter –2.2 dBmV.
The 2715 reverts automatically to the spectral display that now contains a
horizontal line two divisions down (–2.2 dBmV). You will notice the
A register red LED is lit. When you display the line, you cannot display the
contents of the A register. Data stored in A is not destroyed, but you cannot
see it until you turn off the line.
The following steps show another way to set the level of the line:
4. Turn on the marker and set it at the peak of the calibration signal third
harmonic.
5. Press [DSPL] [8].
6. Press [3] to select DISPLAY LINE TO MARKER.
The spectral display reappears with a horizontal line at the marker position. This
provides a convenient way to identify all signals greater or less than another
signal. If the marker is not turned on when item 3 is selected, you receive an
error message.
7. Press [DSPL] [8].
8. Press [4] to select LIMIT DETECTOR.
The end-of-line status indicator changes to OVER; the display line has been
made an upper limit. If an on-screen signal goes over the limit, the audio
alarm sounds.
9. Press [DSPL] to return to the spectral display.
The alarm should be sounding. When the limit detector and the display line
are both selected, the marker automatically turns on and moves to the highest
signal peak on screen. This feature enables you to quickly read the amplitude
of the largest signal after the alarm alerts you that the limit has been
exceeded.
10. Press [DSPL] [8].
11. Press [2] and enter a new value of 23.8 dBmV for the display line.
The alarm should stop because all signals are now below the limit.
12. Press [DSPL] [8] [4].
The status indicator changes to UNDER. The display line has now changed
to a lower limit; the alarm will sound when all signals on screen are under
the limit.
13. Press [DSPL] to return to the spectral display. The alarm should be
sounding.