Product specifications

16
Option SIM provides a spectrogram that provides a
three-dimensional display of the spectrum with power
over frequency and time. This feature helps find intermit-
tent interference signals, as well as locate and identify
unwanted signals that cause dropped calls and poor quality
service in communications systems. The X-axis represents
frequency as in a normal spectrum display, but amplitude
is represented by color: red for a strong signal and blue for
noise floor. The Y-axis represents time, with the trace from
the newest sweep displayed at the bottom of the screen.
Earlier traces move up towards the top of the screen with
each new sweep. Two coupled markers allow you to place
a marker on any trace in the spectrogram and view the nor-
mal spectrum for the time of that sweep. The time interval
between sweeps can be adjusted, and up to 1,500 traces
can be displayed and saved.
In this demonstration, the N9311X-500 whip antenna is
used to receive over the air GSM uplink signal. For interfer-
ence hunting application, a directional antenna like the
N9311X-504 is recommended.
Demonstration 6
Spectrum monitoring and interference hunting
Instructions for HSA Keystrokes for HSA
Set the update interval time
between two frames
{Update Int. (On)}, rotating
knob or pressing numeric
keypads to set the update
interval time
Turn on Marker 1 and Marker 2
(Note: Marker 1 is on by
default)
[MARKER], {Marker (2)},
{State (On)}
Move marker to the location
by setting frequency or time
{Frequency} or {Time},
rotating knob or pressing
numeric keypads to change
the marker’s location as
desired
Turn on file logging
Note: There are manual and
automatic methods to save
data, and the filename’s
format is <Prefix>_<Index>_
HHMMSS
• <Prefix> is N934X by
default, you can edit the
<Prefix> by pressing {File
Path}, {Setup}, {Prefix Edit},
input the name in the “Save
as” dialog box, [Enter]
• <Index> is 0, 1, 2, 3….
• HHMMSS is the time to
start saving
[Meas], {File Logging}
Manual save data
Note: To stop saving press
{Stop Save}
{Start Save}
Automatic save data
Note: To stop saving pressing
{Return}, {Stop Save}
{Timed Setting}, {Start Date},
date format is YYMMDD,
such as: [20100712], [Enter],
{Start time}, time format
is HHMMSS, such as:
[145945], [Enter], {Stop date},
[20100712], [Enter], {Stop
time}, [133000], [Enter], {Time
Save (On)}
Recall the saved spectrogram
file and playback (Figure 20)
[Shift], [File], rotating knob
and highlight the spectrogram
file, {Recall}, {Spctrg View},
{Playback}, {Play}
Figure 20. Spectrum
Instructions for HSA Keystrokes for HSA
Connect the N9311X-500 whip
antenna to the N934xC HSA
RF input connector
Set the center frequency and
span
[FREQ], {Center Freq}, [925],
{MHz}, [Span], [70], {MHz}
Set Y scale/div and On Hi-
Sensitivity to On
Note: If Hi-Sensitivity is On,
parameters below can be set
automatically:
• Reference level -50 dBm
• Attenuator 0 dB
• Preamp On
[Amptd], {Scale/Div},
{5/DIV}, {More 1 of 2},
{Hi-Sensitive (On)}
Turn on spectrum monitor
(N934xC-SIM option needed)
[Meas], {Spectrum Monitor}