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Continuously Variable Slope Delta Modulation
Continuously variable slope delta modulation (CVSD or CVSDM) is a voice coding method. It is a delta modulation with variable step size (i.e., special case of adaptive delta modulation), first proposed by Greefkes and Riemens in 1970. CVSD encodes at 1 bit per sample, so that audio sampled at 16 kHz is encoded at 16 kbit/s. The encoder maintains a reference sample and a step size. Each input sample is compared to the reference sample. If the input sample is larger, the encoder emits a ''1'' bit and adds the step size to the reference sample. If the input sample is smaller, the encoder emits a ''0'' bit and subtracts the step size from the reference sample. The encoder also keeps the previous ''N'' bits of output (''N'' = 3 or ''N'' = 4 are very common) to determine adjustments to the step size; if the previous ''N'' bits are all 1s or 0s, the step size is increased. Otherwise, the step size is decreased (usually in an exponential manner, with \tau being in the ran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speech Coding
Speech coding is an application of data compression to digital audio signals containing speech. Speech coding uses speech-specific parameter estimation using audio signal processing techniques to model the speech signal, combined with generic data compression algorithms to represent the resulting modeled parameters in a compact bitstream. Common applications of speech coding are mobile telephony and voice over IP (VoIP). The most widely used speech coding technique in mobile telephony is linear predictive coding (LPC), while the most widely used in VoIP applications are the LPC and modified discrete cosine transform (MDCT) techniques. The techniques employed in speech coding are similar to those used in audio data compression and audio coding where appreciation of psychoacoustics is used to transmit only data that is relevant to the human auditory system. For example, in voiceband speech coding, only information in the frequency band 400 to 3500 Hz is transmitted but the re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A-law Algorithm
An A-law algorithm is a standard companding algorithm, used in European 8-bit PCM digital communications systems to optimize, i.e. modify, the dynamic range of an analog signal for digitizing. It is one of the two companding algorithms in the G.711 standard from ITU-T, the other being the similar μ-law, used in North America and Japan. For a given input x, the equation for A-law encoding is as follows: F(x) = \sgn(x) \begin \dfrac, & , x, < \dfrac, \\ ex \dfrac, & \dfrac \leq , x, \leq 1, \end where is the compression parameter. In Europe, . A-law expansion is given by the inverse function: The reason for this encoding is that the wide |
Delta-sigma Modulation
Delta-sigma (ΔΣ; or sigma-delta, ΣΔ) modulation is an oversampling method for encoding signals into low bit depth digital signals at a very high sample-frequency as part of the process of delta-sigma analog-to-digital converters (ADCs) and digital-to-analog converters (DACs). Delta-sigma modulation achieves high quality by utilizing a negative feedback loop during quantization to the lower bit depth that continuously corrects quantization errors and moves quantization noise to higher frequencies well above the original signal's bandwidth. Subsequent low-pass filtering for demodulation easily removes this high frequency noise and time averages to achieve high accuracy in amplitude, which can be ultimately encoded as pulse-code modulation (PCM). Both ADCs and DACs can employ delta-sigma modulation. A delta-sigma ADC (e.g. Figure 1 top) encodes an analog signal using high-frequency delta-sigma modulation and then applies a digital filter to demodulate it t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse-width Modulation
Pulse-width modulation (PWM), also known as pulse-duration modulation (PDM) or pulse-length modulation (PLM), is any method of representing a signal as a rectangular wave with a varying duty cycle (and for some methods also a varying period). PWM is useful for controlling the average power or amplitude delivered by an electrical signal. The average value of voltage (and current) fed to the load is controlled by switching the supply between 0 and 100% at a rate faster than it takes the load to change significantly. The longer the switch is on, the higher the total power supplied to the load. Along with maximum power point tracking (MPPT), it is one of the primary methods of controlling the output of solar panels to that which can be utilized by a battery. PWM is particularly suited for running inertial loads such as motors, which are not as easily affected by this discrete switching. The goal of PWM is to control a load; however, the PWM switching frequency must be sele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continuously Variable Slope Delta Modulation
Continuously variable slope delta modulation (CVSD or CVSDM) is a voice coding method. It is a delta modulation with variable step size (i.e., special case of adaptive delta modulation), first proposed by Greefkes and Riemens in 1970. CVSD encodes at 1 bit per sample, so that audio sampled at 16 kHz is encoded at 16 kbit/s. The encoder maintains a reference sample and a step size. Each input sample is compared to the reference sample. If the input sample is larger, the encoder emits a ''1'' bit and adds the step size to the reference sample. If the input sample is smaller, the encoder emits a ''0'' bit and subtracts the step size from the reference sample. The encoder also keeps the previous ''N'' bits of output (''N'' = 3 or ''N'' = 4 are very common) to determine adjustments to the step size; if the previous ''N'' bits are all 1s or 0s, the step size is increased. Otherwise, the step size is decreased (usually in an exponential manner, with \tau being in the ran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Codec
A codec is a computer hardware or software component that encodes or decodes a data stream or signal. ''Codec'' is a portmanteau of coder/decoder. In electronic communications, an endec is a device that acts as both an encoder and a decoder on a signal or data stream, and hence is a type of codec. ''Endec'' is a portmanteau of encoder/decoder. A coder or encoder encodes a data stream or a signal for transmission or storage, possibly in encrypted form, and the decoder function reverses the encoding for playback or editing. Codecs are used in videoconferencing, streaming media, and video editing applications. History Originally, in the mid-20th century, a codec was a hardware device that coded analog signals into digital form using pulse-code modulation (PCM). Later, the term was also applied to software for converting between digital signal formats, including companding functions. Examples An audio codec converts analog audio signals into digital signals for transmissi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sirius Systems Technology
Sirius Systems Technology was a personal computer manufacturer in Scotts Valley, California. It was founded in 1980 by Chuck Peddle and Chris Fish, formerly of MOS Technology and capitalized by Walter Kidde Inc. In late 1982 Sirius acquired Victor Business Systems (known for its calculators and cash registers) from Kidde and changed its name to Victor Technologies. It made the Victor/Sirius series of personal computers. The company made a public stock offering in the first half of 1983, but went into Chapter 11 protection from bankruptcy before the end of 1984. The company's assets were acquired by Datatronic AB, a Swedish software/hardware distribution company headed by . Gabrielsson signed a distribution deal with Kyocera, which began to supply PC clones to Victor. Victor 9000 / Sirius 1 The Victor 9000 (distributed in the UK by British company Applied Computer Techniques as the ACT Sirius 1, and in Australia by Barson Computers as the Sirius 1) was design ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Shuttle (pinball)
''Space Shuttle'' (full title: ''Space Shuttle: Pinball Adventure'') is a Space Shuttle The Space Shuttle is a retired, partially reusable launch system, reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. ... themed pinball machine designed by Barry Oursler and Joe Kaminkow and produced in 1984 by Williams Electronics. The machine's marketing slogan is "The fastest way to make your earnings really take off!". It is notable for its central ramp shot up a feature themed after the Space Shuttle. A sequel, ''Space Station: Pinball Rendezvous'', was released in 1987. Gameplay In ''Space Shuttle'' the main goal is to acquire the shuttle score value from spelling out "S H U T T L E" by hitting six stand up targets and one drop target - or by using the lit inlanes (if available). The reward for the shuttle score value is assigned randomly with each ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gorgar
''Gorgar'' is a 1979 pinball machine designed by Barry Oursler and released by WMS Industries, Williams Electronics. It was the first speech synthesis, speech-synthesized ("talking") pinball machine, containing a vocabulary of seven words ("Gorgar", "speaks", "beat", "you", "me", "hurt", "got") that were combined to form varying broken-English phrases, such as "Gorgar speaks" and "Me got you". The pinball machine also has a heartbeat sound effect that increases in speed during longer gameplay. According to the game's programmer, Paul Dussault, "the voice was John Doremus, an announcer in Chicago that we recorded and then digitized his voice. He was the voice of the in flight audio for various airlines. We had tried in house voices but weren’t getting the bass effect we wanted to make Gorgar sound menacing." Also a promotional record for the machine titled ''Gorgar Speaks'' was produced by Bud Solk & Associates and recorded at Zenith Cinema Service Studios. John Doremus was the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smash TV
''Smash TV'' is a 1990 arcade video game created by Eugene Jarvis and Mark Turmell for Williams Electronics Games. It is a twin-stick shooter in the same vein as 1982's '' Robotron: 2084'', which was co-created by Jarvis. The Super Nintendo Entertainment System, Genesis, Master System, and Game Gear versions are titled ''Super Smash TV''. The game takes place in a dystopian television game show in the then-future year of 1999. One or two contestants shoot waves of attackers while collecting money, prizes, and temporary power-ups. After an arena has been cleared of adversaries, the contestants choose an exit, each leading to another room. One room contains an end-of-level boss. With two players, the game is cooperative, but at the end of the level the player who collected the most cash and prizes receives an extra reward. The arcade game has a high difficulty and leans on being able to pay to continue. A bonus feature was added after release allowing players to collect keys th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinistar
''Sinistar'' is a 1983 multidirectional shooter arcade video game developed and manufactured by Williams Electronics. It was created by Sam Dicker, Jack Haeger, Noah Falstein, RJ Mical, Python Anghelo, and Richard Witt. Players control a space pilot who battles the eponymous Sinistar, a giant, anthropomorphic spacecraft. The game is known for its use of digitized speech and high difficulty level. Although not ported standalone to home consoles, ''Sinistar'' was included in multiple arcade compilations. A sequel from a different developer and publisher, '' Sinistar: Unleashed'' was released for Microsoft Windows in 1999. Gameplay The player pilots a lone spacecraft, flying through a large region of space, part of which is shown on the mini-map at the top of the screen. Shooting drifting planetoids releases small, white crystals. When collected, each crystal turns into a "Sinibomb", which is the weapon for defeating the end of level boss, Sinistar, an animated spacecraf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
μ-law Algorithm
The μ-law algorithm (sometimes written Mu (letter), mu-law, often abbreviated as u-law) is a companding algorithm, primarily used in 8-bit PCM Digital data, digital telecommunications systems in North America and Japan. It is one of the two companding algorithms in the G.711 standard from ITU-T, the other being the similar A-law. A-law is used in regions where digital telecommunication signals are carried on E-1 circuits, e.g. Europe. The terms PCMU, G711u or G711MU are used for G711 μ-law. Companding algorithms reduce the dynamic range of an audio signal. In analog systems, this can increase the signal-to-noise ratio (SNR) achieved during transmission; in the digital domain, it can reduce the quantization error (hence increasing the signal-to-quantization-noise ratio). These SNR increases can be traded instead for reduced Bandwidth (signal processing), bandwidth for equivalent SNR. At the cost of a reduced peak SNR, it can be mathematically shown that μ-law's non-linear q ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
