Analogue/Digital Tv: Measuring The Carrier / Noise Ratio (C/N) - Promax US TV EXPLORER 2 User Manual

5.14.5 Analogue/Digital TV: Measuring the Carrier / Noise ratio (C/N)

The US TV EXPLORER II carries out C/N ratio measurement in four different
ways, according to the carrier type and the used band:
A) Terrestrial band, analogue carrier
Carrier level is measured using a quasi-peak detector (230 kHz BW). Noise level
is measured with an average detector and corrected to refer it to channel
equivalent noise bandwidth (according to the definition of the selected standard).
B) Terrestrial band, digital carrier
Both measurements are done with an average detector (230 kHz) and the same
corrections are introduced on them (bandwidth corrections).
C) Satellite band, analogue carrier
Carrier level is measured using a quasi-peak detector (4 MHz BW). Noise level is
measured with an average detector (230 kHz) and corrected to refer it to channel
bandwidth.
D) Satellite band, digital carrier
Equivalent to case B but now using the 4 MHz BW filter.
On selecting the Carrier / Noise measurement mode the screen displays the
following information:
0
FREQ:
CH:
Figure 27.- Carrier-to-noise ratio measurement (C/N).
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USER'S MANUAL. US TV EXPLORER II
10 20 30
168.25 MHz LEVEL: 78.2
S10 » C/N 40.1
V/A: 16.2
FM DEV: - - -
40
dBµV
dB
dB
kHz
10/2007