Functional Block Diagram - Blonder Tongue Laboratories Inc.

Broadband Specification Guide
CATV Terms & Definitions
Heterodyne
The process of mixing (beating) two frequencies together to generate
frequencies of their sum and difference. This process is used for
channel conversion.
1. Combining two carriers to generate a new carrier which may be either
the sum or difference addition of the original frequencies.
2. To shift a carrier frequency to a new frequency by combining it with
another carrier which is locally generated.
Heterodyne Signal Processor
A unit employed in CATV systems to convert a carrier frequency to
an intermediate frequency (IF). The intermediate frequency carrier
may then be filtered, regulated, or otherwise conditioned, and then
heterodyned back to either the original carrier frequency, or to a
completely new carrier frequency.
Highband
The radio spectrum between 174 and 216 megahertz (MHz). Standard
television channels 7 through 13 fall within this spectrum.
High-Split
Two-way cable communication frequency plan, where the diplex filter’s
cross-over frequency is in the high-band. Consists of an incoming
frequency range of 7-186 MHz and an out-going of 222-450 MHz.
Home Run Cabling
Wiring method where each subscriber is fed via a dedicated drop cable.
Horsepower
A unit of mechanical power equivalent to 550 foot-pounds per second,
or to 745.7 Watts.
HRC
Harmonically Related Carriers. Frequencies plan used by some CATV
companies which provides for lower perceived distortion levels in
cascaded amplifiers. HRC channels assignments with the exception of
channels 5 and 6 (.75 MHz higher than standard).
Hum Modulation
Undesired low frequency modulation of a carrier at the frequency of the
source of the interference, or a harmonic of that frequency, usually 60 Hz
or 120 Hz, for example.
Hybrid System
In Cable Television systems, this refers to a system that incorporates
lightwave transmission on optical fibers for a part of the system, and
extends the plant on RF broadband coaxial cables for distribution and
connection to subscribers.
Hydroxylion Absorption
Absorption of optical power in optical fiber due to hydroxyl (OH) ions. This
absorption has to be minimized for low fiber loss.
Hyperband
CATV channels AA thru YY (numeric equivalents -37 thru 61) falling in the
frequency range of 300 to 450 MHz.
IDF
Short for intermediate distribution frame, a cable rack that interconnects
and manages the telecommunications wiring between an MDF and
workstation devices. Cables entering a building run through a centralized
MDF, then each individual IDF and then on to specific workstations. For
example, an enterprise that encompasses a building with several floors
may have one MDF on the first floor and one IDF on each of the floors
that is connected to the MDF.
Index Matching Material
A material, often a liquid or cement, whose refractive index is nearly
equal to an optical element index. Material with an index nearly equal
to that of an optical fiber's core is used in splicing and coupling to reduce
reflections from the fiber end face.
Index Profile
A characteristic of an optical fiber which describes the way its index of
refraction changes with its radius.
Impedance
Circuit characteristic) voltage divided by current). TV distribution has
standardized on 75 ohm and 300 ohm.
Insertion Loss
The loss introduced into a cable or system by the Insertion of a device or
network expressed in decibels. See Loss.
Instructional Television Fixed Service (ITFS)
ITFS is a microwave transmission in the frequency range of 2500-
2686 MHz used by educational entities for distributing programming
employing analog TV transmissions. This band was also referred to as
MMDS and was used by wireless cable operators. The FCC has since
re-designated this band as BRS (Broadband Radio Service) and EBS
(Educational Broadband Service) and has established provisions for
digital transmissions.
Interference
Noise or other disturbances such as spurious signals that, when
introduced to a desired signal, reduce the intelligibility of the information
carried on that signal.
Intermodulation Distortion
The distortion introduced when several or many carriers are passed
through a nonlinear circuit. This includes the spurious signals (beats)
produced as sum and difference additions of the carriers present, and
the transfer or superimposition of modulating information from one
carrier to another.
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