Promax PROLINK-4 Manual De Instrucciones página 194

4.9.4.22 Exit
Exits from the TV functions menu.
4.10 Spectrum Analyser Operating Mode
The Spectrum Analyser mode allows the user to discover the signals present in the
frequency band in quickly and easily and to make measurements at the same time. To select it
press key [21]. The monitor will show a picture like the one described in the next figure.
The horizontal lines define the signal level, the broken lines being 5 dB from the
solid ones. The level of the top line (80 dBµV in previous figure), named the Reference
Level, can be altered using the Reference level function in the Spectrum Analyser mode
functions menu (section 4.10.1.3).
The signal level for each frequency is displayed vertically, the lower frequencies
appearing 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
37 dBµV and the lobe with the highest signal level (second from the left) is at 64 dBµV.
The frequency range displayed (called span from hereon) can also be altered
using the Spectrum Analyser mode functions menu.
A vertical broken line, called marker, appears on the spectrum display to
identify the tuned frequency.
One of the applications of the PROLINK-4 operating as 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.
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Figure 39.- Spectrum Analyser mode.
USER'S MANUAL. PROLINK-4
02/2003