60 Cycle Hum

These hum bars at 60 cycles are normally a result of dc power on the line. See dcBlocker.

A/B Switch

A switch that selects one of two inputs (A or B) for routing to a common output while providing adequate isolation between the two signals.

Adjacent Channel

An adjacent channel is one which is immediately next to another channel.

AFC

A circuit which locks an electronic component onto a chosen frequency.

AGC

Controlling the gain of a device by the signal level through the device (using a high gain feedback loop circuit). A rising input signal level produces a negative feedback signal, which lowers the gain. A circuit that uses feedback to maintain the output of an electronic component at a constant level.

Agile Component

A component which can be tuned to any desired channel.

Amplifier

A device used to increase the power of a signal.

Analog

A system in which signals vary continuously in contrast to a digital system in which signals vary in discrete steps.

Antenna

A device that contributes an energy gain. Satellite dishes, broadband antenna and cut-to-channel antennas are some types of antennas encountered in private cable systems.

Antenna Pre-Amplifier

An amplifier located in the immediate vicinity of the antenna, used to amplify extremely weak signals, thereby improving the signal-to-noise ratio of a system.