18WuD2x

common-mode input circuit • commutating capacitor 131
common-mode input circuit In a differential amplifier,
the input circuit between ground and the
inputs connected together.
common-mode input impedance In a differential
amplifier, the open-loop impedance between
ground and the inputs connected together. Compare
COMMON-MODE IMPEDANCE INPUT.
common-mode input signal A signal applied to
the common-mode input circuit of a differential
amplifier (i.e., to both inputs connected together).
Compare COMMON-MODE SIGNAL.
common-mode input voltage In a differential amplifier,
the maximum voltage that can be applied
safely between ground and the inputs connected
together.
common-mode interference A form of interference
that occurs across the terminals of a
grounded system.
common-mode rejection The extent to which a
differential amplifier will reject a signal presented
simultaneously to both inputs in phase,
or of two signals identical in amplitude, frequency,
and phase applied separately to the two
inputs. Also see COMMON-MODE REJECTION
RATIO.
common-mode rejection ratio In a differential
amplifier, the extent to which the amplifier cancels
undesired signals. It is the ratio of the differential
gain to the common-mode gain. Also see
COMMON-MODE REJECTION.
common-mode signal The algebraic average of
two signals applied simultaneously to the two
ends of a balanced circuit, such as a differential
amplifier. Compare COMMON-MODE INPUT SIG-
NAL.
common-mode voltage The part of the input that
is common to both inputs of a differential amplifier
circuit. It is quantitatively defined as the
arithmetic mean of the voltages at the inputs.
common-mode voltage gain See COMMON-
MODE GAIN.
common-mode voltage range The range limited
by the maximum nonsaturating input voltage
that can be applied to both inputs of an operational
amplifier.
common pool An assigned memory store, utilized
by two or more circuits or systems.
common-resistor coupling The process of coupling
one circuit to another by means of a resistor
that is common to both circuits.
Input
L1
C1
C2
R1
(Common
resistor)
common-resistor coupling
L2
Output
common-source circuit A field-effect transistor
circuit in which the source terminal is the
common (or grounded) electrode. Also called
grounded-source circuit.
common-user channels Communication channels
open to all licensees in a particular service.
communication band A band of frequencies
whose use is authorized expressly for communications,
rather than for other services (such as
broadcasting, education, remote control, etc.).
communication channel 1. In radio or wire service,
a (usually auxiliary) channel for direct exchange
of information between units of the
service (e.g., a “talking circuit” between a broadcast
studio and the transmitter house). 2. A data
transmission channel between two points (e.g., a
remote terminal and a central computer system).
communication link 1. Collectively, the equipment
providing a communication channel between
two transmitters. 2. Data terminal
equipment.
communication protocol The specifications of a
digital signal, including the speed in bits per second
(bps) or bauds, the code type, the bit duration,
the mark-to-space ratio, etc.
communications The science and art of using and
developing electronic equipment and processes
for the transmission and reception of information.
communications common carrier An organization
licensed to provide public communication
services.
communications network An organization of
transmitting and receiving stations for the reliable
exchange of intelligence. Also called net.
communications receiver A general-coverage or
multiband radio receiver, designed primarily for
listening to amateur, weather, or other nonbroadcast
stations. Compare BROADCAST RE-
CEIVER.
communications satellites Satellites in earth orbit
that provide propagation paths (e.g., by reflection
or retransmission) for radio waves between
terrestrial transmitters and receivers. Also see
ACTIVE COMMUNICATIONS SATELLITE and
PASSIVE COMMUNICATIONS SATELLITE.
community-antenna television Abbreviation,
CATV. A system in which an advantageously located
receiving station receives television signals,
amplifies them if necessary, and distributes them
in the community served by the system. Commonly
called cable TV.
commutating capacitor 1. In a flip-flop circuit, a
capacitor connected in parallel with the crosscoupling
resistor to accelerate the transition from
one stable state to the other. Also called speedup
capacitor. 2. A capacitor connected in parallel between
silicon-controlled rectifier (SCR) stages to
momentarily reverse the current going through
the SCR, thereby causing the SCR to go into the
cutoff condition.