In the External power supply mode the unit powering the amplifiers before the
antenna (terrestrial television) or the satellite TV receiver (house-hold or community)
also powers the external units.
The DRAIN [6] indicator lights when current is flowing to the external unit. If any
kind of problem occurs (e.g., a short circuit), an error message appears on the monitor
('SUPPLY SHORT'), the acoustic indicator will be heard and the instrument will cease
to supply power. The PROLINK-3/3C
state until the problem has been solved.
4.9 TV Operating Mode
4.9.1 Selecting the Measurement Mode (MEASURE)
The types of measurements available depend on the band, the standard and the
operating mode.
Terrestrial band - Analogue channels:
Level
Video / Audio
C / N
Terrestrial band - Digital channels:
Channel power
C/N
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Level measurement of the currently tuned carrier.
Video carrier to audio carrier level ratio.
Ratio between the modulated signal power and the
equivalent noise power fora same bandwidth. There are two
methods to make this measurement (selectable through the
C/N setup function):
Auto: In-channel measurement. Noise level is measured at
a frequency where modulation contents is minimum. After a
small period of time, minimum measured level corresponds
to noise level.
Referenced: The user defines the frequency where noise
level will be measured (by means of the Reference noise
function). This frequency will be used to measure noise
level for all channels.
Automatic method: channel power is measured assuming
that power spectral density is uniform throughout channel
bandwidth. To measure it correctly it is indispensable to
define the Channel BW.
Two methods selectable through the C/N setup function:
Auto: Out-channel measurement. Noise level is measured
at f noise = f tuning - ½*Channel BW. To measure it correctly
digital channel must be tuned at its central frequency.
Referenced: The user defines the frequency where noise
level will be measured (by means of the Reference noise
function). This frequency will be used to measure noise
level for all channels.
USER'S MANUAL. PROLINK-3/3C
does not return to its normal operating
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06/2005