Tabla de contenido
Idiomas disponibles
Idiomas disponibles
USER'S MANUAL. PROPOWER-5
4.2.3.1 Channel tuning
4.2.3.1.1 Power and C/N ratio measurement of digital PLC channels.
When a PLC digital channel is tuned, the
PROPOWER-5 will display a screen as the one
shown in the attached figure.
The tuned channel (UL4 in the figure) appears
in the higher left hand corner; this may be changed
by turning the rotary selector [9]. At its right appears
the frequency (10.50 MHz) and the active channel
plan (IBER in the figure).
Below a screen as shown in the attached figure will appear. This screen shows
the digital CHANNEL POWER (-10 dBm in the example) together with its related
channel bandwidth (BW=2.5 MHz) and the Carrier/Noise ratio (C/N=48 dB). At the
bottom of the screen a bar-graph represents the channel power, with a resolution of
1 dB.
In order to measure digital channels correctly, previously, the channel must be
configured (see Edit Channel Plan function at section '4.2.1 Unit Global
Configuration), if necessary, the CHANNEL BW parameter should be redefined by
means of the Channel-Frequency configuration menu. When a channel has been
defined as digital, the PROPOWER-5 tunes it at its central frequency.
Digital channels power measurement is carried out by means of an integration
method. The PROPOWER-5 divides the bandwidth of the channel (CHANNEL BW) in
sections of 230 kHz (4 by each MHz approximately) and measures the contribution of
each one to the total power of the channel. This way, a very exact measurement is
obtained, specially in the case of degraded channels, because the channel flatness is
had in consideration.
Figure 15.- Measuring the power of a digital channel by integration.
The C/N ratio measurement shows the ratio between the digital PLC channel
power and the noise power. The user can define the frequency where the noise power
must be measured. Two possibilities exist:
07/2006
Figure 14.- Measuring a digital
channel.
VERY IMPORTANT
180 kHz
Page 19
Capítulos
Tabla de contenido
