Peer Reviewed Journal via three different mandatory reviewing processes, since 2006, and, from September 2020, a fourth mandatory peer-editing has been added.
Cable television (CATV) systems generally consist of
a headend, trunk cables, distribution cables in the neighborhood,
drop cables to a home and in-house wiring, and terminal equipment.
Coaxial cables bring a CATV signal to customer premises
through a service drop, an overhead or underground cable.
Hermetic inline amplifiers are used to amplify the attenuated
CATV signal due to propagation loss or splitting the coaxial cable.
They are usually installed on utility poles. Therefore, maintenance
methods for inline amplifiers on utility poles are important issues
in CATV operations. This paper proposes a new maintenance
system for inline amplifiers in CATV systems, and develops a
prototype implementation. The proposed system consists of an
amplifier gain analyser to measure amplification performance of
inline amplifiers, a special smartphone application, and a cloud
server. The proposed amplifier gain analyser is composed of three
functions: a generation of high frequency signals for testing,
measurement of the test signal gain, and wireless communication
based on Bluetooth Low Energy (BLE). We develop a signal
generation circuit for a test signal and a smoothing circuit for
converting the high frequency test signals into DC signals. The
amplifier gain analyser can evaluate an amplifier gain by comparing
an input test signal from the signal generation circuit and an
output test signal from an inline amplifier. The measurement
function uses Nordic nRF51822, which is a System on Chip
(SoC) for BLE because Nordic nRF51822 has some AD converter
ports for evaluating the DC signals. The smartphone application
employs BLE communication function to collect the measured
amplifier gain from the amplifier gain analyser. Therefore, we
developed a special data collection application for iOS. The
data collection application has a central function of BLE, and
can find a target peripheral device that is the amplifier gain
analyser in this paper. Therefore, technicians of CATV systems
can easily check the operational status of inline amplifiers on
utility poles. Additionally, the smartphone application can upload
the measured information to a cloud storage server. We employ
Google App Engine and use Cloud Datastore to implement the
cloud storage service. Therefore, our storage service has flexibility
for various kinds of information.
