Appendix D.- Carrier To Noise Ratio (C/N) - Promax -4 Manual De Uso

APPENDIX D.- CARRIER TO NOISE RATIO (C/N)
The Carrier to Noise ratio is a measurement of the signal quality. The power of
the noise measured changes according to the resolution filter utilized. However, in TV it
is usual to refer the noise level to a bandwidth of 5 MHz. If the measurement is reduced
to a different bandwidth, the user must apply a simple correction. The PROMAX-4 takes
the measurement in a noise bandwidth of 5 MHz.
N :
L
N = N
L measurement
There is some standards that determine the minimum C/N value for an
installation. In general greater values than 40 dB are considered good quality signals.
Lower than 40 dB you can see snow or graininess at the display.
Page 30
C/N = C – N
L
dependes on the measurement bandwidth
+ 10 log (BWx / BW
USER'S MANUAL. PROMAX-4
(dB)
L
)
measurement
Novembre 1999