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Topic: Frequency modulation synthesis

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	MusicDspWiki - Fm Synthesis (Site not responding. Last check: 2007-11-05)
		Frequency modulation synthesis is a simple but efficient synthesis algorithm.
		The reason for that is that if the modulating waveform is a sine, the result is going to end up being the same (and for other waveforms, the result will be as if the sound is frequency modulated by the derivate on the modulating signal).
		Frequency choices are not limited to multiples of the played note - if they are slightly detuned, there will be a slow variation in the resulting sound.
	www.musicdsp.org /phpWiki/index.php/FmSynthesis (632 words)

	Digital Music online course - Basic Frequency Modulation Synthesis Technique
		Sound engineers tend to refer to the carrier frequency as the fundamental frequency, but musicians often avoid this nomenclature because in music the term "fundamental frequency" is normally associated with pitch and in FM the carrier frequency does not always determine the pitch of the sound.
		The frequency ratio is a useful tool for the implementation of a phenomenon that is very common among conventional instruments, that is, achieving variations in pitch whilst maintaining the timbre virtually unchanged.
		If the frequency ratio and the modulation index of a simple FM instrument are maintained constant but the offset carrier frequency is modified then the sounds will vary in pitch, but their timbre will remain unchanged.
	x2.i-dat.org /~csem/UNESCO/5 (1349 words)

	FM - The real meaning from Timesharetalk wikipedia (Site not responding. Last check: 2007-11-05)
		Frequency modulation (FM) is a form of modulation which represents information as variations in the instantaneous frequency of a carrier wave.
		(Contrast this with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant.) In analog applications, the carrier frequency is varied in direct proportion to changes in the amplitude of an input signal.
		Note that frequency modulation can be regarded as a special case of phase modulation where the carrier phase modulation is the time integral of the FM modulating signal.
	www.timesharetalk.co.uk /wiki.asp?k=FM (1063 words)

	Digital Synthesis
		These sidebands are symmetrically spaced about the frequency of the carrier[3], and the size of the spaces is equal to the frequency of the modulator.
		At low modulation index, you will hear two distinct pitches in the tone; as the index is increased, the timbre of the upper pitch seems to become brighter.
		By applying an envelope function to the amount of modulation or the frequencies of carrier and modulator, sounds can be produced that have a life and excitement far beyond that available with the older synthesis methods.
	arts.ucsc.edu /ems/music/tech_background/TE-17/teces_17.html (876 words)

	Frequency modulation synthesis
		In essence FM is the modulation of the frequency parameter of an oscillator with a signal in the audio range, meaning that FM can be used on any oscillator that lets itself be smoothly controlled in frequency at audio range.
		The frequency of the carrier is the reference frequency to define the ratio, meaning that the ratio can be simply calculated by dividing the modulator frequency by the carrier frequency, while using the values in Hertz for the division.
		At the modulator side it is especially the pulse wave that is very suitable, as it will have the effect of alternatingly change the slope direction of the waveform, which works especially well on a triangle carrier waveform.
	www.xs4all.nl /~rhordijk/Proto/FM.htm (1820 words)

	Hubert Howe, Music 733.2 lab 4
		Frequency modulation synthesis was invented by John Chowning in the late 1960s and implemented by Yamaha in its DX-7 synthesizer, which was the most successful synthesizer ever at the time it was introduced.
		The tone that is modulated is called the carrier frequency, and the tone that does the modulation is called the modulating frequency or simply modulator.
		The amount of modulation or frequency deviation is called the modulating index, and it is measured in relation to the modulating frequency.
	qcpages.qc.cuny.edu /~howe/music733.2/lab4.html (1511 words)

	FM Tutorial
		Frequency Modulation (or FM) synthesis is a simple and powerful method for creating and controlling complex spectra, introduced by John Chowning of Stanford University around 1973.
		When the frequency of the modulator (which we'll call M) is in the sub-audio range (1-20 Hz), we can hear siren-like changes in pitch of the carrier.
		That is, the distance in frequency between adjacent sidebands is unequal.
	www.sfu.ca /~truax/fmtut.html (2588 words)

	Types of Synthesis - The Sonic Spot
		When the modulation signal is used to quickly cycle the carrier signal's amplitude, like AM synthesis it forms two additional sidebands, but the carrier signal is cancelled out and disappears.
		RM synthesis is used by Vocoders which are often used to effect a human voice's sound signal to create a "robotic" sounding variation.
		Frequency Modulation (FM) Synthesis produces an output signal by oscillating the frequency of a source oscillator's signal.
	www.sonicspot.com /guide/synthesistypes.html (983 words)

	Computer Music: FM Synthesis
		Frequency Modulation is a technique not just limited to sound synthesis but has been used in radio transmission since around 1935 (Edwin Armstrong, "A Method of Reducing Disturbances in Radio Signaling by a System of Frequency Modulation").
		The actual MODULATION INDEX (I) is the ratio of the frequency of the carrier wave to the amplitude of the modulating signal.
		The FREQUENCY DEVIATION is equivalent to the AMPLITUDE of the modulating signal.
	www.ec.vanderbilt.edu /computermusic/musc216site/FM.synthesis.html (1204 words)

	FM (Site not responding. Last check: 2007-11-05)
		--> In frequency modulation the amplitude is kept constant and the frequency is modulated by the amplitude of the modulating signal.
		The frequency spectrum can be found by rewriting the above expression as a sum of components of constant frequency using the properties of the Bessel Functions.
		Applet below shows a modulating signal in orange, the FM signal in red, the frequency spectrum in fl and how they vary with the modulation index and modulating frequency.
	cnyack.homestead.com /files/modulation/modfm.htm (101 words)

	Introduction to FM (Frequency Modulation) Synthesis - Article at Scott R. Garrigus' DigiFreq
		Modulation synthesis is a waveshaping technique in which an audio-rate signal called the modulator controls some parameter of another audio signal, called the carrier.
		In FM, the frequency is the modulated parameter.
		A signal with frequency —F is simply inverted (180 degrees out of phase) with respect to a frequency F. In this particular example, the negative frequencies wouldn’t affect the sound.
	www.digifreq.com /digifreq/article.asp?ID=31 (960 words)

	Frequency Modulation Synthesis (2/2)
		In FM Synthesis - part 1, a basic rule of thumb was given to determine the frequency of sidebands.
		While the frequencies of sidebands are fairly easy to calculate, thier amplitudes is a much more complex story, and typically involves the constructive and destructive interference of negative frequencies rebounding into the positive frequency domain.
		;; again the value of the modulation index is given a dependency ;; with respect to amplitude and frequency: the frequency relationship ;; is as in the duration calculation, and the amplitude relation is now ;; a multiple.
	ccrma.stanford.edu /software/clm/compmus/clm-tutorials/fm2.html (1499 words)

	Frequency modulation synthesis - Wikipedia, the free encyclopedia
		For synthesizing harmonic sounds, the modulating signal must have a harmonic relationship to the original carrier signal.
		FM synthesis is a form of "distortion synthesis" or "nonlinear synthesis".
		The ratio of deviation to modulation frequency is called the "index of modulation".
	en.wikipedia.org /wiki/Frequency_modulation_synthesis (747 words)

	FM (Site not responding. Last check: 2007-11-05)
		In analog applications, the carrier frequency is varied in direct proportion to changes in the amplitude of an input signal.
		Frequency modulation requires a wider bandwidth than amplitude modulation by an equivalent modulating signal, but this also makes the signal more robust against interference.
		Frequency-shift keying refers to the simple case of frequency modulation by a simple signal with only discrete states, such as in Morse code or radio-teletype applications.
	www.yournursery.com /search.php?title=FM (931 words)

	Frequency and phase modulation
		are called the carrier frequency, the modulation frequency, and the index of modulation, respectively.
		It is customary to use a simpler, essentially equivalent formulation in which the phase, instead of the frequency, of the carrier sinusoid is modulated sinusoidally.
		We can analyze the result of phase modulation as follows, assuming that the modulating oscillator and the wavetable are both sinusoidal, and that the carrier and modulation frequencies don't themselves vary in time.
	www-crca.ucsd.edu /~msp/techniques/latest/book-html/node78.html (562 words)

	Advanced Sound-Synthesis in OSW (Site not responding. Last check: 2007-11-05)
		In wavetable synthesis, a small waveform is stored in a table, which in OSW can be either a Table or SampleBuffer, and treated as a single period of a repeating waveform.
		Although this technique is more accurlately called "phase modulation" the name "frequency modulation" is still used in practice and the behavior of this patch is similar to the technique used in "classic FM" synthesizers[Chowning 1985].
		Granular synthesis is an alternative to additive synthesis that is based on a theory developed by Gabor [Roads 1988].
	osw.sourceforge.net /html/advanced.html (2626 words)

	Synthesis and Control of Hundreds of Sinusoidal Partials on a Desktop Computer without Custom Hardware
		Another important aspect of additive synthesis is the simplicity of the mapping of frequency and amplitude parameters into the human perceptual space.
		This is in contrast to the parameter space of the frequency modulation synthesis method which maps awkwardly to the spectral domain through Bessel functions [Corrington 1970].
		Then, at the synthesis stage, it is easy to compute the frequency of a partial, retaining control of the amount of inharmonicity in the resulting sound.
	www.cnmat.berkeley.edu /~adrian/FFT-1/FFT-1_ICSPAT.html (3611 words)

	Sound Synthesis
		One way to do this is to simply add various amplitudes of the harmonics of a chosen pitch until the desired timbre is obtained, called additive synthesis.
		Another way is to start with geometric waves, which are rich in harmonic content, and filter the harmonics to produce a new sound- subtractive synthesis.
		Modern sound synthesis makes increasing use of MIDI for sequencing and communication between devices.
	hyperphysics.phy-astr.gsu.edu /hbase/audio/synth.html (615 words)

	Digital Music online course - Advanced Frequency Modulation synthesis
		In this case, however, the modulating signal is a frequency modulated signal.
		The sideband frequencies are calculated using the same method used above for parallel modulators, but the calculation of the amplitude scaling factors is different.
		This scheme will always produce a sawtooth-like waveform due to the fact that it works with a 1:1 frequency ratio by default; that is, the modulation frequency is equal to its own frequency.
	x.i-dat.org /~csem/UNESCO/6/index.html (577 words)

	audio-rate frequency modulation
		This article explains the phenomenon of audio-rate frequency modulation of sound, which was explored and used compositionally by John Chowning of Stanford University around 1970.
		The rate of the vibrato is determined by the modulator's frequency, the depth of the vibrato (or how far above and below its center frequency the carrier will be pushed) is determined by the modulator's amplitude and the shape of the vibrato is determined by the modulator's waveform.
		The greater the amplitudes of the modulating wave are at its peaks, the greater the maximum distance the carrier is pushed off its center frequency.
	www.indiana.edu /~emusic/fm/fm.htm (2969 words)

	UTSA Electronic Music Studio Web Site: FM Synthesis (Site not responding. Last check: 2007-11-05)
		FM: The instantaneous frequency of a carrier wave is varied according to a modulator wave such that the rate at which the carrier varies is the rate of the modulating wave, or modulating frequency.
		Modulation index: the modulation index measures the peak deviation of the carrier from its average.
		Reflected sideband frequencies: The special richness of FM lies in the fact that there are ratios of c and m and values of the index that can produce sideband components which fall into the negative domain of the spectrum.
	music.utsa.edu /comp/fm.htm (293 words)

	Frequency Modulation
		The process of modulation means to systematically use the information signal (what you want to transmit) to vary some parameter of the carrier signal.
		To modulate the signal just means to systematically vary one of the three parameters of the signal: amplitude, frequency or phase.
		The modulation index is normally limited to a value between 1 and 5, depending on the application.
	www.fas.org /man/dod-101/navy/docs/es310/FM.htm (1801 words)

	FM synthesis - Glossary - CNET.com (Site not responding. Last check: 2007-11-05)
		There are two main ways to synthesize music: frequency modulation, and sampling from a wavetable.
		FM synthesis uses a signal to modulate the frequency of another signal, and the results sound like arcade games from the 1970s or one of the first wave of poker-faced European techno-bands.
		In general, however, FM synthesis is not as desirable an asset in your sound circuitry as wavetable synthesis.
	www.cnet.com /Resources/Info/Glossary/Terms/fmsynthesis.html (90 words)

	Frequency Modulation (FM) Synthesis
		The top-most wavetable is called the 'modulator' because it is not heard directly, just indirectly via the effect it has on the bottom wavetable, which is called the 'carrier'.
		For example, if the carrier frequency is 400hz and the modulator frequency is 600hz, then the C:M ratio is 1.5.
		The second imporant variable is the amplitude of the modulator, called the 'modulation index.' The modulation index will effect the loudness of the sideband overtones, so the higher the modulation index the more prominent the n overtones will be.
	jmusic.ci.qut.edu.au /jmtutorial/FMSynthesis.html (388 words)

	Digital Synthesis of Musical Sounds
		When John M. Chowning proposed the application of the frequency modulation (FM) technique as used in radio transmission to the synthesis of complex musical sounds [Journal of Audio Engineering Society, Sept. 1973, 21:526-534] in 1973, the technology of musical sound synthesis was significantly advanced.
		The use of AFM in synthesis results in a more effective method of waveform synthesis and can possibly lead to generation of new sounds which are beyond the capabilities of other synthesis methods.
		When John M. Chowning proposed the application of the frequency modulation (FM) technique as used in radio transmission to the synthesis of complex musical sounds [14] in 1973, the technology of musical sound synthesis was significantly advanced.
	xenia.media.mit.edu /~gan/Gan/Education/NUS/Physics/MScThesis (706 words)

	Basic Frequency Modulation (Site not responding. Last check: 2007-11-05)
		A signal flow diagram describing simple frequency modulation (FM) with sinusoidal oscillators is shown in Fig.
		Using sinusoidal waveforms for both the carrier and modulator, this modulation produces additional spectral components in the output signal at multiples of
		FM.m provides an aural and visual demonstration of the modulator's affect on the resulting FM spectrum.
	www.music.mcgill.ca /~gary/307/week10/node14.html (133 words)

	Modulation (Site not responding. Last check: 2007-11-05)
		Without going in-depth into FM synthesis and the use of its technical terms, it can basically be described as the output produced when one operator modulates the frequency of another.
		PD synthesis and FM synthesis, as used in Yamaha's DX range, were often lumped into the same category, and although they use similar synthesis techniques, they are most certainly very different beasts.
		Now what happens in PD synthesis is that your output swings between a sine wave and a square wave at a specific frequency, giving you an almost filtering effect.
	www.analoguesque.com /modsynthesis.htm (4721 words)

	Programming sounds in FM Synthesis \| How to Program Frequency Modulation Synthesis, basics of FM programming
		A formant is a frequency or a group of frequencies that doesn't change as the fundamental changes.
		Choosing anything but a sine wave as a carrier or modulator multiplies the number and intensity of the sidebands, because each overtone in a more complex wave serves as a separate carrier or modulator, generating new sidebands that are added to the mix.
		Reducing a modulator's amplitude at the low end of the keyboard, for example, produces bass notes with fewer overtones, which is helpful because it prevents the bass from overpowering instruments that are playing in the midrange.
	emusician.com /tutorials/emusic_operators_standing (1523 words)

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