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Voice Activity Detection
Voice activity detection (VAD), also known as speech activity detection or speech detection, is the detection of the presence or absence of human speech, used in speech processing. The main uses of VAD are in speech coding and speech recognition. It can facilitate speech processing, and can also be used to deactivate some processes during non-speech section of an audio session: it can avoid unnecessary coding/transmission of silence packets in Voice over Internet Protocol (VoIP) applications, saving on computation and on network bandwidth. VAD is an important enabling technology for a variety of speech-based applications. Therefore, various VAD algorithms have been developed that provide varying features and compromises between latency, sensitivity, accuracy and computational cost. Some VAD algorithms also provide further analysis, for example whether the speech is voiced, unvoiced or sustained. Voice activity detection is usually independent of language. It was first investigat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speech Processing
Speech processing is the study of speech signals and the processing methods of signals. The signals are usually processed in a digital representation, so speech processing can be regarded as a special case of digital signal processing, applied to speech signals. Aspects of speech processing includes the acquisition, manipulation, storage, transfer and output of speech signals. The input is called speech recognition and the output is called speech synthesis. History Early attempts at speech processing and recognition were primarily focused on understanding a handful of simple phonetic elements such as vowels. In 1952, three researchers at Bell Labs, Stephen. Balashek, R. Biddulph, and K. H. Davis, developed a system that could recognize digits spoken by a single speaker. Pioneering works in field of speech recognition using analysis of its spectrum were reported in 1940s. Linear predictive coding (LPC), a speech processing algorithm, was first proposed by Fumitada Itakura of N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conference Call
A conference call is a telephone call in which someone talks to several people at the same time. The conference call may be designed to allow the called party to participate during the call or set up so that the called party merely listens into the call and cannot speak. It is sometimes called ATC (audio teleconference). Conference calls can be designed so that the calling party calls the other participants and adds them to the call; however, participants are usually able to call into the conference call themselves by dialing a telephone number that connects to a "conference bridge," which is a specialized type of equipment that links telephone lines. Companies commonly use a specialized service provider who maintains the conference bridge, or who provides the phone numbers and PIN codes that participants dial to access the meeting or conference call. These service providers can often dial-out to participants, connecting them to call and introducing them to the parties who are o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Predictive Dialer
A predictive dialer dials a list of telephone numbers and connects answered dials to people making calls, often referred to as agents. Predictive dialers use statistical algorithms to minimize the time that agents spend waiting between conversations, while minimizing the occurrence of someone answering when no agent is available.Predictive Dialing for Outbound Telephone Call Centers Douglas A. Samuelson, Interfaces, 29:5 September–October, 1999 (pp. 66-81). When dialing numbers one at a time, there are two sources of delay. First, only some fraction of dials are answered; for example, if 1 out of 3 dials are answered, a predictive dialer might dial 3 lines every time an agent becomes available. Second, even dials that are answered take some time before being picked up. If it typically takes 10 seconds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Random Access Memory
Random-access memory (RAM; ) is a form of computer memory that can be read and changed in any order, typically used to store working Data (computing), data and machine code. A Random access, random-access memory device allows data items to be read (computer), read or written in almost the same amount of time irrespective of the physical location of data inside the memory, in contrast with other direct-access data storage media (such as hard disks, CD-RWs, DVD-RWs and the older Magnetic tape data storage, magnetic tapes and drum memory), where the time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement. RAM contains multiplexer, multiplexing and demultiplexing circuitry, to connect the data lines to the addressed storage for reading or writing the entry. Usually more than one bit of storage is accessed by the same address, and RAM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Consumption
Electric energy consumption is the form of energy consumption that uses electrical energy. Electric energy consumption is the actual energy demand made on existing electricity supply for transportation, residential, industrial, commercial, and other miscellaneous purposes. Global electricity consumption in 2019 was 22,848 terawatt-hour (TWh), about 135% more than the amount of consumption in 1990 (9,702 TWh). China, United States, and India accounted for over 50% of the global share of electricity consumption. Overview Electric energy is most often measured either in joules (J), or in watt hours (W·h). : 1 W·s = 1 J : 1 W·h = 3600 W·s = 3600 J Electric and electronic devices consume electric energy to generate desired output (i.e., light, heat, motion, etc.). During operation, some part of the energy is lost depending on the electrical efficiency. Electricity has been generated in power stations since 1882. The invention of the steam turbine in 1884 to drive the electr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Simultaneous Voice And Data
Digital usually refers to something using discrete digits, often binary digits. Technology and computing Hardware *Digital electronics, electronic circuits which operate using digital signals **Digital camera, which captures and stores digital images ***Digital versus film photography **Digital computer, a computer that handles information represented by discrete values **Digital recording, information recorded using a digital signal Socioeconomic phenomena *Digital culture, the anthropological dimension of the digital social changes *Digital divide, a form of economic and social inequality in access to or use of information and communication technologies *Digital economy, an economy based on computing and telecommunications resources Other uses in technology and computing *Digital data, discrete data, usually represented using binary numbers *Digital marketing, search engine & social media presence booster, usually represented using online visibility. *Digital media, media sto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discontinuous Transmission
Discontinuous transmission (DTX) is a means by which a mobile telephone is temporarily shut off or muted while the phone lacks a voice input. Misconception A common misconception is that DTX improves capacity by freeing up TDMA time slots for use by other conversations. In practice, the unpredictable availability of time slots makes this difficult to implement. However, reducing interference is a significant component in how GSM and other TDMA based mobile phone systems make better use of the available spectrum compared to older analog systems such as Advanced Mobile Phone System (AMPS) and Nordic Mobile Telephone (NMT). While older network types theoretically allocated two 25–30 kHz channels per conversation, in practice some radios would cause interference on neighbouring channels making them unusable, and a single radio may broadcast too strong an oval signal pattern to let nearby cells reuse the same channel. GSM combines short packet sizes, frequency hopping, redundan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CDMA
Code-division multiple access (CDMA) is a channel access method used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communication channel. This allows several users to share a band of frequencies (see bandwidth). To permit this without undue interference between the users, CDMA employs spread spectrum technology and a special coding scheme (where each transmitter is assigned a code). CDMA optimizes the use of available bandwidth as it transmits over the entire frequency range and does not limit the user's frequency range. It is used as the access method in many mobile phone standards. IS-95, also called "cdmaOne", and its 3G evolution CDMA2000, are often simply referred to as "CDMA", but UMTS, the 3G standard used by GSM carriers, also uses "wideband CDMA", or W-CDMA, as well as TD-CDMA and TD-SCDMA, as its radio technologies. It can be also used as a channel or m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cellular Radio
A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive telephone call, calls over a radio frequency link while the user is moving within a telephone service area. The radio frequency link establishes a connection to the switching systems of a mobile phone operator, which provides access to the public switched telephone network (PSTN). Modern mobile telephone services use a cellular network architecture and, therefore, mobile telephones are called ''cellular telephones'' or ''cell phones'' in North America. In addition to telephony, digital mobile phones (2G) support a variety of other GSM services, services, such as text messaging, Multimedia Messaging Service, multimedia messagIng, email, Internet access, short-range wireless communications (Infrared Data Association, infrared, Bluetooth), business applications, video games and dig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bit Rate
In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time. The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction with an SI prefix such as kilo (1 kbit/s = 1,000 bit/s), mega (1 Mbit/s = 1,000 kbit/s), giga (1 Gbit/s = 1,000 Mbit/s) or tera (1 Tbit/s = 1,000 Gbit/s). The non-standard abbreviation bps is often used to replace the standard symbol bit/s, so that, for example, 1 Mbps is used to mean one million bits per second. In most computing and digital communication environments, one byte per second (symbol: B/s) corresponds to 8 bit/s. Prefixes When quantifying large or small bit rates, SI prefixes (also known as metric prefixes or decimal prefixes) are used, thus: Binary prefixes are sometimes used for bit rates. The International Standard ( IEC 80000-13) specifies different a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Universal Mobile Telecommunications System
The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the International Telecommunication Union IMT-2000 standard set and compares with the CDMA2000 standard set for networks based on the competing cdmaOne technology. UMTS uses wideband code-division multiple access (W-CDMA) radio access technology to offer greater spectral efficiency and bandwidth to mobile network operators. UMTS specifies a complete network system, which includes the radio access network (UMTS Terrestrial Radio Access Network, or UTRAN), the core network (Mobile Application Part, or MAP) and the authentication of users via SIM (subscriber identity module) cards. The technology described in UMTS is sometimes also referred to as Freedom of Mobile Multimedia Access (FOMA) or 3GSM. Unlike EDGE (IMT Single-Carrier, based on GSM) and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephony
Telephony ( ) is the field of technology involving the development, application, and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is intimately linked to the invention and development of the telephone. Telephony is commonly referred to as the construction or operation of telephones and telephonic systems and as a system of telecommunications in which telephonic equipment is employed in the transmission of speech or other sound between points, with or without the use of wires. The term is also used frequently to refer to computer hardware, software, and computer network systems, that perform functions traditionally performed by telephone equipment. In this context the technology is specifically referred to as Internet telephony, or voice over Internet Protocol (VoIP). Overview The first telephones were connected directly in pairs. Each user had a separate telephone wired ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
