Voiceband

Voiceband

In electronics, voiceband means the typical human hearing frequency range that is from 20 Hz to 20 kHz. In telephony, it means the frequency range normally transmitted by a telephone line, generally about 200–3600 Hz. Frequency-division multiplexing in telephony normally uses 4 kHz carrier spacing. The rate at which the amplitude of a signal drops off near the upper and lower limits can vary with the design of the band-pass filters.

The question of frequency spacing was addressed at an international meeting in the 1930s. Germany and Britain favored 2 kHz spacing, while the Netherlands and some other countries preferred 6 kHz. The question was compromised at the American position, which was the 4 kHz spacing that remained standard and also fixed the standard PCM sample rate at 8 kHz, which in turn defines what "voiceband" means for this purpose. The abandonment of in-band signaling in the late 20th century made available a larger voiceband for modems and voices.

See also

*A-weighting
*Telephone
*Frequency-division multiplexing
*Time-division multiplexing
*Hearing (sense)

*


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • Voiceband modem operating standards — ▪ Table Voiceband modem operating standards ITU T standard transmission rate modulation method transmission mode V.27ter 4.8 kbps PSK half duplex V.29 9.6 kbps QAM half duplex V.17 14.4 kbps QAM/TCM half duplex V.21 300 bps FSK full duplex V.22 1 …   Universalium

  • voiceband — noun The range of frequencies typically audible to humans, from about 20 Hz to 20 kHz …   Wiktionary

  • VIU — • Voiceband Interface Unit • Video Interface Unit NASA …   Acronyms

  • modem — /moh deuhm, dem/, Computers. n. 1. an electronic device that makes possible the transmission of data to or from a computer via telephone or other communication lines. v.t. 2. to send or receive (information, data, or the like) via a modem.… …   Universalium

  • telecommunication — [tel΄ə kə myo͞o΄ni kā′shən] n. [also pl., with sing. or pl. v.] communication by electronic or electric means, as through radio, telephone, telegraph, television, or computers * * * tel·e·com·mu·ni·ca·tion (tĕlʹĭ kə myo͞o nĭ kāʹshən) n. 1. The… …   Universalium

  • 56 kbit/s modem — 56k modems are voiceband modems nominally capable of download speeds up to 56 kbit/s (56,000 bits per second). At the beginning of the 21st Century, most personal computers contained one, their use declining as broadband technologies such as DSL… …   Wikipedia

  • Echo cancellation — The term echo cancellation is used in telephony to describe the process of removing echo from a voice communication in order to improve voice quality on a telephone call. In addition to improving subjective quality, this process increases the… …   Wikipedia

  • Digital Circuit Multiplication Equipment — (DCME) was a type of voice compression equipment that is installed at either end of a long distance link (typically communications satellite or submarine communications cable). The main characteristics of DCME are defined in ITU T recommendation… …   Wikipedia

  • Modem — For other uses, see Modem (disambiguation). A modem (modulator demodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The… …   Wikipedia

  • Digital subscriber line — DSL redirects here. For other uses, see DSL (disambiguation). DSL technologies Standard ADSL ANSI T1.413 Issue 2 ITU G.992.1 (G.DMT) ITU G.992.2 (G.Lite) ADSL2 ITU G.992.3 ITU G.992.4 ITU G.992.3 Annex J ITU G.992.3 Annex L ADSL2+ …   Wikipedia

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”