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USER'S MANUAL.
PROMAX-8
4.2.3.1
Channel tuning
4.2.3.1.1
Video carrier + V/A + C/N measurement (only for analogue
channels)
If the tuned channel has been defined as
analogue by means of the Edit Channel Plan
function (see section 4. 2.1 Global Configuration
PROMAX-8
Menu), the
as the one shown in the attached figure.
The tuned channel (C69 in the figure)
appears in the higher left hand corner; this may be
changed by turning the rotary selector [9]. At its right appears the frequency (855.25 MHz)
and the active channel plan (CCIR in the figure).
Below is shown the video carrier level, VIDEO Carrier (80 dBμV in the example).
The units of measurement may be changed using the Global Configuration Menu (section
4.2.1). At the bottom, a bar-graph displays the level with a resolution of 1 dB.
Also the ratios between the video and the audio carriers (V/A) and the
video carrier and noise (C/N) are shown. The example in previous figure shows a
channel with a Video/Audio ratio of 16 dB and a C/N ratio of 54 dB.
4.2.3.1.2
Audio carrier measurement and demodulation (only for
analogue channels)
PROMAX-8
For the
demodulate an audio signal and
show its characteristics (level and
frequency offset), press the rotary
selector [9] again. In the attached figure, the audio
carrier level (AUDIO Carrier) is 64 dBμV and the
frequency offset is 5.50 MHz (ΔF). It also shows if
the audio (whether Level, FM or AM) is activated (a
speaker appears) or not (no speaker appears). To
change the audio carrier offset (ΔF) and the audio
modulation (Level, FM or AM) accede the section 4.2.3.5.
4.2.3.1.3
CSO-CTB
analogue channels)
The active devices present in the distribution systems, when working in its
nonlinear zone, generate interferent signals, called distortion products, that can fall
within the video bandwidth. From a certain level this interference becomes visible on the
TV image.
09/2013
SE
SE
will display a screen
SE
to
distortion
products
Figure 14.- V/A and C/N Level
measurement
Figure 15.- Audio demodulation
and measurement.
measurement
(only
for
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