Promax TV EXPLORER HD ISDB-T Manual page 180

The signal level for each frequency is displayed vertically, the lower frequencies
appear at the left of the screen and the higher ones at the right. The amplitude of the
lobes is calibrated. In the example in previous figure the noise level is at around 25 dBµV
and the lobe with the highest signal level (third from the right) is at 70 dBµV.
In the case that the equipment detects saturation on RF input due to an excess of
signal, it will appear the icon
the TV mode to indicate this situation. The user must increase the Reference Level in
order to activate an additional atenuator and to avoid the input saturation.
Speed of sweep can be modified for terrestrial TV signals. To that end, press
shortly the key [17] MEASUREMENT CONFIGURATION. On the menu "Configuration"
it will appear the option "Sweep". Entering in this option you can switch between "Fast"
for a quick sweep of the spectrum or "Accurate" for a slower sweep. This option will only
appear when you're working with terrestrial TV signals, therefore the led "T" on the front
panel must be lighted.
The frequency range displayed (called span from hereon) can also be altered
using the horizontal cursors
screen frequency range in Spectrum Analyser mode between Full (the entire band), 500
MHz, 200 MHz, 100 MHz, 50 MHz, 32 MHz, 16 MH and 8 MHz (the latter one only in
terrestrial band).
A vertical broken line, called marker, appears on the spectrum display to identify
the tuned frequency.
One of the applications of the TV EXPLORER
Spectrum Analyser is in the search for the best orientation and position of the receiving
antenna. This is particularly important in UHF. Because such frequencies are involved,
with wavelengths ranging from 35 cm to 65 cm, if the antenna is shifted only a few
centimetres, the relationship between the picture, chrominance and sound carrier
frequencies change, affecting the quality of the picture in the receiver.
If there is an excess of sound carrier, tearing or 'moiré' may appear on the screen
due to the frequency beats between the sound, chrominance and the picture
frequencies.
If there is a chrominance carrier defect, then the television colour amplifier must
function at maximum gain, which could result in noise appearing all over the television
screen with points of colour that disappear when the saturation control is reduced; in an
extreme case, loss of colour may occur.
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USER'S MANUAL. TV EXPLORER
in the Spectrum Analyser mode and the icon
[6] key. Therefore enables selecting the displayed
HD
HD ISDB-T/T operating as
B
ISDB-T/T
B
in
11/2010