11 Glossary

A

AAC (Advanced Audio Coding)

An audio compression scheme defined as part of the MPEG-2 standard (also known as MPEG- 2 AAC or MPEG-2 NBC, or Not Backwards Compatible). It offers better sound and a compression ratio that is superior by roughly 30 percent compared to the MPEG-1 MP3 format.

AC (alternating current)

An alternating current is an electrical current whose magnitude and direction vary cyclically, as opposed to DC (direct current), whose direction remains constant.The usual waveform of an AC power circuit is a sine wave, as this results in the most efficient transmission of energy. However certain applications use different waveforms, such as triangular or square waves.

Audio output

High-level (speaker) or line-level (RCA) signals sent from one system component to another; or the high-level signal from an amplifier to the system speakers.

C

CBR (constant bit rate)

With CBR the encoder spends the same amount of bits on each frame, regardless of how much it may really need. Disadvantage of CBR: Bits are wasted in case of absolute blackness of a picture or complete silence in an audio frame. And pictures or audio frames with a lot of elements may need those bits.

D

dB (Decibel)

A unit of measure used to express relative difference in power or intensity of sound.

D

DC (direct current)

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Direct current or continuous current is the

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constant flow of electric charge.This is typically

E

 

in a conductor such as a wire. In direct current,

 

the electric charges flow in the same direction,

Glossary

DHCP

distinguishing it from AC (alternating current).

 

DHCP stands for Dynamic Host Configuration

 

Protocol. It is a protocol for assigning dynamic

 

IP addresses to devices on a network.

 

Digital

 

A method to encode information using a binary

 

code of 0s and 1s. Many wireless phones and

 

networks use digital technology.

 

Digital Audio

 

Digital Audio is a sound signal that has been

 

converted into numerical values. Digital sound

 

can be transmitted through multiple channels.

 

Analog sound can only be transmitted through

 

two channels.

 

Duplex (half/full)

Full duplex is the ability to send and receive data simultaneously. Duplex is synonymous with full duplex. Example: when a modem operates in full-duplex mode, it can transmit data in two directions simultaneously. In half-duplex mode it can transmit data in two directions, but not simultaneously.

F

Frequency

The property or condition of occurring at frequent intervals. In sound, this simply refers to the regular occurrence of compression and rarification of air that we experience as sound.

Frequency Response

Is the range of frequencies that a speaker reproduces, lowest frequency to the highest. While the optimal normal is 20-20,000 Hz (Hertz), the range of human hearing for

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Philips NP1100/37 user manual Glossary, Dhcp