Related Research Articles
Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the amplitude of the wave is varied in proportion to that of the message signal, such as an audio signal. This technique contrasts with angle modulation, in which either the frequency of the carrier wave is varied, as in frequency modulation, or its phase, as in phase modulation.
A digital synthesizer is a synthesizer that uses digital signal processing (DSP) techniques to make musical sounds. This in contrast to older analog synthesizers, which produce music using analog electronics, and samplers, which play back digital recordings of acoustic, electric, or electronic instruments. Some digital synthesizers emulate analog synthesizers; others include sampling capability in addition to digital synthesis.
Frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. The technology is used in telecommunications, radio broadcasting, signal processing, and computing.
Frequency modulation synthesis is a form of sound synthesis whereby the frequency of a waveform is changed by modulating its frequency with a modulator. The (instantaneous) frequency of an oscillator is altered in accordance with the amplitude of a modulating signal.
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a separate signal called the modulation signal that typically contains information to be transmitted. For example, the modulation signal might be an audio signal representing sound from a microphone, a video signal representing moving images from a video camera, or a digital signal representing a sequence of binary digits, a bitstream from a computer.
In radio communications, single-sideband modulation (SSB) or single-sideband suppressed-carrier modulation (SSB-SC) is a type of modulation used to transmit information, such as an audio signal, by radio waves. A refinement of amplitude modulation, it uses transmitter power and bandwidth more efficiently. Amplitude modulation produces an output signal the bandwidth of which is twice the maximum frequency of the original baseband signal. Single-sideband modulation avoids this bandwidth increase, and the power wasted on a carrier, at the cost of increased device complexity and more difficult tuning at the receiver.
In signal processing, group delay and phase delay are two related ways of describing how a signal's frequency components are delayed in time when passing through a linear time-invariant (LTI) system. Phase delay describes the time shift of a sinusoidal component. Group delay describes the time shift of the envelope of a wave packet, a "pack" or "group" of oscillations centered around one frequency that travel together, formed for instance by multiplying a sine wave by an envelope.
A signal generator is one of a class of electronic devices that generates electrical signals with set properties of amplitude, frequency, and wave shape. These generated signals are used as a stimulus for electronic measurements, typically used in designing, testing, troubleshooting, and repairing electronic or electroacoustic devices, though it often has artistic uses as well.
Pulse-width modulation (PWM), also known as pulse-duration modulation (PDM) or pulse-length modulation (PLM), is a method of controlling the average power or amplitude delivered by an electrical signal. The average value of voltage 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 selected carefully in order to smoothly do so.
Wavetable synthesis is a sound synthesis technique used to create quasi-periodic waveforms often used in the production of musical tones or notes.
A numerically controlled oscillator (NCO) is a digital signal generator which creates a synchronous, discrete-time, discrete-valued representation of a waveform, usually sinusoidal. NCOs are often used in conjunction with a digital-to-analog converter (DAC) at the output to create a direct digital synthesizer (DDS).
A voltage-controlled oscillator (VCO) is an electronic oscillator whose oscillation frequency is controlled by a voltage input. The applied input voltage determines the instantaneous oscillation frequency. Consequently, a VCO can be used for frequency modulation (FM) or phase modulation (PM) by applying a modulating signal to the control input. A VCO is also an integral part of a phase-locked loop. VCOs are used in synthesizers to generate a waveform whose pitch can be adjusted by a voltage determined by a musical keyboard or other input.
Phase distortion (PD) synthesis is a synthesis method introduced in 1984 by Casio in its CZ range of synthesizers. In outline, it is similar to phase modulation synthesis as championed by Yamaha Corporation, in the sense that both methods dynamically change the harmonic content of a carrier waveform by influence of another waveform (modulator) in the time domain. However, the application and results of the two methods are quite distinct.
In electrical engineering, a function generator is usually a piece of electronic test equipment or software used to generate different types of electrical waveforms over a wide range of frequencies. Some of the most common waveforms produced by the function generator are the sine wave, square wave, triangular wave and sawtooth shapes. These waveforms can be either repetitive or single-shot. Another feature included on many function generators is the ability to add a DC offset. Integrated circuits used to generate waveforms may also be described as function generator ICs.
An arbitrary waveform generator (AWG) is a piece of electronic test equipment used to generate electrical waveforms. These waveforms can be either repetitive or single-shot in which case some kind of triggering source is required. The resulting waveforms can be injected into a device under test and analyzed as they progress through it, confirming the proper operation of the device or pinpointing a fault in it.
John M. Chowning is an American composer, musician, discoverer, and professor best known for his work at Stanford University, the founding of CCRMA - Center for Computer Research in Music and Acoustics in 1975 and his development of the digital implementation of FM synthesis and the digital sound spatialization while there.
The Access Virus is a virtual analog synthesizer made by the German company Access Music GmbH. It was first produced in 1997 and has since been upgraded frequently, with the company releasing new models about every two years. Early models include the Virus A, Virus B, and Virus C series, each available in various hardware configurations. In November 2005, the Virus TI series was released, including the 61-key Virus TI Keyboard and the 37-key Virus TI Polar. A small desktop model was released in February 2008 called the Virus TI Snow. A revision of the TI series called TI2 came out in March 2009, featuring faster digital signal processing (DSP) controllers, additional polyphony, more effects in the effect section and a slightly changed design. The Virus series also has come out with two software plugin versions: TDM for Pro Tools and VST for TC Electronic Powercore series. The term Access Virus can be used to refer to any one of these synthesizers.
In electronic music, waveshaping is a type of distortion synthesis in which complex spectra are produced from simple tones by altering the shape of the waveforms.
The chirp pulse compression process transforms a long duration frequency-coded pulse into a narrow pulse of greatly increased amplitude. It is a technique used in radar and sonar systems because it is a method whereby a narrow pulse with high peak power can be derived from a long duration pulse with low peak power. Furthermore, the process offers good range resolution because the half-power beam width of the compressed pulse is consistent with the system bandwidth.
The OPL series are a family of sound chips developed by Yamaha. The OPL series are low-cost sound chips providing FM synthesis for use in computing, music and video game applications.
References
- ↑ Nb. Some authors refer to these techniques as 'modulation synthesis'; e.g. Chapter 6 of Roads, Curtis (1996). The computer music tutorial. MIT Press.
- ↑ Dodge 1997, pp.115-138
- ↑ Roads, Curtis (June 1979). "A Tutorial on Non-Linear Distortion or Waveshaping Synthesis". Computer Music Journal. MIT Press. 3 (2): 29–34. doi:10.2307/3680281. JSTOR 3680281.
- ↑ Dodge 1997, pp.139-157
- ↑ Dodge 1997, pp.158-168
- ↑ J. Chowning (1973). "The Synthesis of Complex Audio Spectra by Means of Frequency Modulation". Journal of the Audio Engineering Society. 21 (7).
- ↑ Arfib, D. 1979. "Digital synthesis of complex spectra by means of multiplication of non-linear distorted sine waves." Journal of the Audio Engineering Society 27: 10.
- ↑ Marc Le Brun. "Digital Waveshaping Synthesis" in Journal of the Audio Engineering Society, 27(4), 1979, p250-266.
- ↑ Moorer, J. A. (November 1976). "The Synthesis of Complex Audio Spectra by Means of Discrete Summation Formulae". Journal of the Audio Engineering Society, 27(4), pp.717-727.
- ↑ T Stilson; J Smith (1996). "Alias-free digital synthesis of classic analog waveforms". Proc. Int. Comp. Music Conf. (ICMC'96 Hong Kong): 332–335. CiteSeerX 10.1.1.60.4437 .
- ↑ C. Roads 1996, p.260-61.
- Dodge, Charles; Thomas A. Jerse (1997). "5. Synthesis Using Distortion Techniques". Computer Music . New York: Schirmer Books. pp. 115–168. ISBN 0-02-864682-7.
- Chowning, John; Bristow, David (1986). FM Theory & Applications - By Musicians For Musicians. Tokyo: Yamaha. ISBN 4-636-17482-8.
