Promax US TV EXPLORER II Manual De Uso página 77

USER'S MANUAL. US TV EXPLORER
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 on 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 attenuator and to avoid the input saturation.
Speed of sweep can be modified for terrestrial TV signals. To that end, press
shortly the key
"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) can also be altered using the
horizontal cursor
frequency range in Spectrum Analyzer mode between Full (the entire band), 500 MHz,
200 MHz, 100 MHz, 50 MHz, 32 MHz, 16 MHz 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 US TV EXPLORER
Analyzer is to 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
centimeters, the relationship between the picture, chrominance and sound carrier
frequencies changes, 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 color amplifier must
function at maximum gain, which could result in noise appearing all over the television
screen with points of color that disappear when the saturation control is reduced; in an
extreme case, loss of color may occur.
11/2013
II
in the Spectrum Analyzer mode and the icon
[17] MEASUREMENT CONFIGURATION. On the menu
[6] key. Therefore enables selecting the displayed screen
II operating as Spectrum
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