UNAOHM
EP2500 (Rev. 0)
25
7.11
MEASUREMENT BANDWIDTH.
The instrument provides two bandwidths (100 kHz and 1 MHz), which are indicated as “N” (narrow) or
“W” (wide) on the OSD. The alternate selection between the two available values is carried out by
means of the key
BW
.
NOTE
:
The command is available only in the
SPEC
,
EXP
,
MEA
modes (see section 7.12,
OPERATING MODES).
There is no criterion for the selection of one of the two bandwidths: indicatively the wider one is
preferable, because it is less critical, unless it is necessary to differentiate between adjacent signals. A
typical case when it is necessary to use a narrow bandwidth is the measurement of the analogue stereo
subcarrier, only 250 kHz away from the mono subcarrier and FM radio signals.
7.12
FUNCTION
The instrument has five operating fucnctions:
1.
Spectrum analyser (
SPECT
rum). To rapidly explore a vast band of frequencies and thereby
immediately locate the signals present .
2.
Expanded spectrum (
SPAN)
. It is similar to
SPECT
rum, but the frequency band explored is
narrower, allowing for a more detailed analysis.
3.
(
MEA
sure). In this function the majority of measurements are carried out and is the only valid one
for level measurements.
4.
TV
. The instrument operates as a normal TV.
5.
Monitor (
EXT
ernal
)
. Reproduces external video and audio signals.
To pass from one mode to another use the multifunction keys
(4)
.
7.13
SPECTRUM ANALYSER FUNCTION
To enter the spectrum analyser mode press the key
SPEC
. In this operating mode the entire band
selected is displayed on the screen. The band frequency coverage is shown in the box on the screen. To
scroll through the frequency bands (C, L, M, H, S) press
RANGE (36)
.
On the screen, a marker overlapping the spectrum shows the tuning frequency.
The upper box in the middle of the
OSD
display
shows (see
Figure 5
for the terrestrial band and
Figure
9
for the SAT band):
•
The level in connection with the marker position.
NOTE
:
to get the most accurate level reading it is necessary to pass to
MEA
sure mode.
The lower box in the middle of the
OSD
display
will show:
•
The marker frequency.
•
The channel number related to the marker frequency, if a channel format has been set.
•
The program (
pr
in lower case letters = location empty,
PR
in capital letters = location being used.
•
The operating band.
•
The set LNB voltage (not necessarily applied).
•
22 kHz tone insertion.
•
The attenuation engaged.
The measurement bandwidth, W (wide) or N (narrow) and the type of demodulator in use appear on the
multifunction keys
(4)
.
