Satellite band - Analogue channels:
Level
C/N
Satellite band - Digital channels
Channel power
C/N
Like in the TV mode, to select the type of measure, press key
the rotary selector [4] until desired mode is marked and finally press the rotary selector
[4] or key
[22] to activate the new measurement mode.
4.10.2.1
Measuring Carrier Levels (Level)
(Only for analogue channels). When selecting this mode on the lower part of the
image appears the tuned frequency (or channel) and the signal level at this frequency. If
dual marker function is selected, tuned frequency and signal level are showed for each
one of the markers and, on the far right, the frequency difference and the level between
them.
4.10.2.2
Measuring the Carrier / Noise ratio (C/N Referenced)
The Carrier/Noise ratio in Spectrum mode is always referenced to a noise
frequency defined by the user.
Imagine a situation like the one shown in the next figure: a digital channel (8 MHz
BW) adjacent to an analogue channel. When measuring C/N for the digital channel in
TV mode using the Auto setup, the analogue channel may interfere in the noise
measurement (given that the noise level is measured at f noise =f tuning - ½* Channel
BW = 650 MHz - 4MHz = 646 MHz), so under this situation it is recommended to make
the measurement in Spectrum Analyser mode and to define manually the frequency
where we want to measure noise (obviously a frequency where no signal is present);
i.e. in the next figure noise is defined to be measured at 655 MHz.
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Level measurement of the currently tuned carrier.
Video carrier to noise ratio referenced to a noise frequency
defined by the user through the Reference Noise function.
Integration method.
Referenced: Channel level to noise ratio referenced to a
noise frequency defined by the user through the Reference
Noise function.
USER'S MANUAL. PROLINK-3/3C
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[22] then turn
06/2005