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Wavetable-modification instrument and method for generating musical sound
2010-03-12
multiplications and additions to formeach sample. That process requires digital circuitry which is both expensive and inflexible. Accordingly, the digital design necessary to carry out the method of harmonic summation is computationally complex and leaves much to be desired.

Another known type of musical instrument employs the filtering method of music generation. In the filtering method, a complex electrical waveform, such as a square wave or a saw-tooth pulse train, is filtered by one or more filters to select thedesired frequency components. Thereafter, the filtered frequency components are combined to form the electrical signal which drives the speaker. The filtering method is commonly used to synthesize human speech and has often been used with analogelectronic organs. The filtering method is comparatively inflexible since each sample relies upon the stored values of fixed samples. In order to achieve natural sound, the filtering method requires a large number of multiplication steps which areeconomically expensive to achieve.

In a typical example of a filter technique, a waveshape memory provides digital samples of one cycle of a waveshape to a loop circuit which includes a filter and a shift register. The digital waveshape samples read out from the waveshape memoryare caused to circulate at a predetermined rate of time in the loop circuit. A output from the loop circuit varies as time lapses, and is utilized as a musical tone.

The classical filter techniques result in systems in which the pitch frequency fs /N, is determined by division using an integer, N, and hence desirable variations due to non-integral division are not achieved.

In many prior art systems, the divisor, N, is forced to be an integer when shift-register or other fixed circuits are employed. Also, the integer is further limited to some power of 2 in order to facilitate processing. In order to vary thepitch, fs /N, the frequency fs must be varied. Such systems, however, cannot be extended readily and economically to multi-voice embodiments because, for example, each voice requires a different frequency, fs.

Both the harmonic summation and the filtering methods rely upon a linear combination of sinusoids and, hence, they are characterized as linear methods for generating musical sound. The linear property is apparent from the fact that multiplyingthe amplitude of the input function (sinusoids for harmonic summation or a pulse train for filtering) by a factor of two results in an output waveform with the same tone quality and with an amplitude multiplied by a factor of two.

U.S. Pat. No. 4,018,121 entitled METHOD OF SYNTHESIZING A MUSICAL SOUND to Chowning describes a non-linear method for generating musical sound. That nonlinear method employs a closed-form expression (based upon frequency modulation) torepresent the sum of an infinite number of sinusoids. That non-linear frequency modulation method produces a number of sinusoids which have frequencies which are the sum of the carrier frequency and integral multiples of the modulation frequency. Theamplitudes of the multiples of the modulation frequency are sums of Bessel functions. The non-linear frequency modulation method of Chowning is an improvement over previously used linear harmonic summation and filtering methods, and has found commercialapplication in music synthesizers.

U.S. Pat. No. 4,215,617 entitled MUSICAL INSTRUMENT AND METHOD FOR GENERATING MUSICAL SOUND to Moorer describes improved non-linear methods of musical sound generation in which the amplitudes of frequency components are not constrained to theBessel functions and in which finite spectra can be utilized, that is, spectra composed of the sum of a finite number of sinusoids.

In general, prior art methods of musical sound generation have employed deterministic techniques. Typically, the methods rely upon an input sample which has fixed parameters which specify the musical sound to be generated. Such input sampleswhen processed by a predetermined method result in a deterministic output signal which does not have the rich, natural sound of more traditional instruments.

While many linear and non-linear methods, like those described above, have been used with success for digital musical synthesis, they all have required fast and complex computational capability typically involving several multiplication steps persample in order to achieve rich, natura...

Method for encoding music printing information in a MIDI message
2010-03-10
a long and distinguished history. The origins of the modern system can be traced as far back as the 10th Century AD with notation of early church chant. These simple melodies were made up entirely of the notes of what we today call the diatonic scale. This is the origin of the "white" keys on the modern keyboard. Early chant was not composed in what we today call the major-minor system of keys but rather in an older system call modes. All modes used the same diatonic scale tones, but each mode started at a different degree (note) of the diatonic scale. Thus, for example, the Dorian Mode started on what we today call the diatonic pitch of D and consisted of the notes, D, E, F, G, A, B, C. This mode sounds a lot like the modern key of D minor, but includes a "raised" sixth degree (the note B instead of the B-鈾?that would be called for in modern D minor.

The system for notating pitch in chants and other early music was quite simple. A set of lines was drawn (sometimes four, sometimes five, sometimes more than five), and the degrees of the scale were represented as positions on the lines or on the spaces in between them. This is the origin of our modem five-line staff system. In the case of the Dorian mode referred to above, the notation of the scale would look as shown in FIG. 1.

The important thing to notice is that each degree (note) of the scale has a position that is one level higher than the previous degree, but that the actual size of musical interval between two consecutive degrees is not the same in all cases. For example, the size of musical interval between D and E is what we today call a whole step. In terms of sound frequency, the pitch E is on the order of 12.24 percent higher than the pitch D (the actual size will depend on the system of tuning used). The size of the musical interval between E and F is what we today call a half step. In terms of sound frequency, the pitch F is on the order of 5.94 percent higher than the pitch E. To restate the point in another way, the levels on the musical staff do not all represent the same size musical interval.

The modern system of major-minor keys, which is the basis of practically all music written and/or performed today (both classical and popular), grew out of the earlier modal system. What allowed the major-minor system to develop was the ability to alter selectively the basic pitches of the modes either by raising them with what we today call a sharp (#), or lowering them with what we today call a flat (鈾?. The amount by which a pitch is raised or lowered by a sharp or a flat is a half-step, about 5.94 percent of the base (starting) frequency. The Dorian scale in the previous example can be made into a D-mi...

Control system for a musical instrument
2010-03-09
to prevent leakage of air through the neoprene material. Neoprene material of the above-dimensions is preferred as it has a tactile feel which allows the musician 100 to depress the material to a known depth. Specifically, in the preferred embodiment, the tactile member 106 exerts a known, predictable amount of force against the finger of the musician when the musician is depressing the tactile member 106 until the point where the central chamber 124 of the member 106 has been pinched off. Hence, the musician 100 can become acquainted with the extent to which he must depress the tactile member 106 to produce a given change in pressure within the tactile member 106.

The tactile members 106 are preferably glued to the surface of the musical instrument 102 so that they project outward from the musical instrument 102 in the positions shown in FIGS. 1 and 2. This further facilitates the musician 100 in depressing the tactile member 106 in a controlled fashion as it allows the musician 100 to depress the tactile member 106 towards a surface. Since the tactile members 106 are positioned on the outer surfaces of the musical instrument 102, the musician 100 can position the members 106 in a desired location and change the position of the members whenever he desires by simply removing the member from one location and gluing it to another.

FIG. 4 illustrates the control box 108 in greater detail. Specifically, the control box 108 includes a power on-off switch 200 and an auxiliary power port 202. The control box 108 preferably includes an internal battery (See, FIG. 5) but is equipped to operate on either batteries or from an external power source.

The control box 108 also includes a tube input 204 to receive the pressure signal from the tactile member 106 and an electrical input 206 which receives the audio signal from the musical instrument 102. In the preferred embodiment, the musical instrument is an electric guitar which produces an electrical signal indicative of the notes played on the strings via a plurality of magnetic pickups associated with the strings. The electrical signal from the musical instrument 102 is then processed by the control box 108 in the manner described hereinbelow and an output signal is then provided via an electrical output 210 to a sound system, e.g., an amplifier (not shown), where in an audio signal is produced.

The control box 108 also includes a program mode select button 212 and a program mode LED 214. The program mode select button 212 enables the musician 100 to program the control box 108 to perform manipulations to the audio signal produced by the musical instrument using a plurality of select buttons 216, 218 and 220. The select buttons include the volume select button 216, the tremolo speed select button 218 and the tremolo depth or amplitude button 220. The operation of these buttons varies depending upon whether the control box 108 is in a program mode or in a play mode.

In the program mode, the volume select button 216 enables the musician 100 to program a set starting volume for the signal produced by the musical instrument 102. Further, in the program mode the tremolo speed select button 218 enables the musician 100 to program a plurality of different frequencies, i.e., speeds, for a tremolo effect on the sound signal produced by the musical instrument. Finally, in the program mode the tremolo depth button 220 enables the musician 100 to select a plurality of different amplitudes for a tremolo effect, e.g., volume levels, on the audio signal produced by the musical instrument 102.

In the play mode, the volume select button 216 can be selected by the musician 100 to induce the control system 104 to perform one of two functions. In the first function, the control system 104 modifies the audio signal produced by the musical instrument 102 so that the volume characteristic is dependent upon the pressure that the musician 100 is exerting on the tactile member 106. In the second function, the control box 108 modifies the audio signal produced by the musical instrument 102 so that the volume characteristic of the audio signals is sustained at a particular value. In this function, while the musician 100 is playing the instrument 102, he is depressing on the tactile member 106 thereby causing the volume characteristic to increase. The control system 104 sustains the volume characteristic at the volume that corresponds to the maximum amount of pressure that the musician 100 exerted on the tactile member 106.

Further, in the play mode, the tremolo speed select button 218 enables the musician 100 to select the frequency or speed of the tremolo effect as one of three preset frequencies. The preset frequencies are generally frequencies that the musician has preprogrammed into the control system 104 in the program mode as described above. The musician 100 is also capable of increasing the frequency from one of the pre-programmed frequencies by depressing on the tactile member 106. The control system 104 increases the frequency at a rate which is proportional to the amount of pressure exerted on the tactile member 106 by the musician 100.

Finally, in the play mode, the tremolo depth button 220 allows the musician 100 to change the volume, i.e., the amplitude, of the tremolo effect on the audio signal produced by the musical instrument 102. In the preferred embodiment, the musician 100 can change the volume between a plurality of different pre-programmed volumes.

Hence, the control box 108 permits the musician 100 to program various parameters for different sound characteristics and then, when playing the instrument, use the pre-programmed parameters to alter different sound characteristics. In the preferred embodiment, the volume select, tremolo speed select and tremolo depth select buttons 216, 218, 220 are all lighted by LEDs 216a, 216b, and 216c which facilitate the musician 100 in programming the control box 108 and using the control box 108 while playing the musical instrument 102.

FIG. 5 is an electrical schematic which illustrates the components of a control circuit 109 positioned in the control box 108 that enable the control system 104 to perform the above-described operations. The control circuit 109 includes a controller 300 which, in the preferred embodim...

Musical apparatus detecting maximum values and/or peak values of reflected light beams to control musical functions
2010-03-08
of an object in an operation space, and where the musical control instructions are varied by changing the state of motion of the object in space.The musical apparatus performs musical control instructions whose contents are based on the state of motion of an object in motion within a specified operation space. The musical apparatus may have at least one light source which shines light into said operation space, at least one light sensor which receives light which has been reflected by an object in the space so that it has at least two light paths which reach from the light source to the light sensor via the object, so that a detection values is output according to the quantity of light received via a respective one of the light paths, and a musical controller which outputs music and controls a musical function when the correlation between the current values of the detection values of the various paths satisfies a specified relationship.Claims

We claim:

1. An electronic musical system which responds to the motion of an object within a specified space to control a sound function, wherein the electronic musical system comprises:

at least one radiation source that emits radiation into the specified space;

at least one sensor that receives radiation reflected along at least two different paths from an object in the specified space and provides at least one detection value corresponding to a characteristic of radiation received from the two paths; and

a controller for generating a control signal for operating the sound function based on the detection value.

2. The system of claim 1, wherein the at least one radiation source that emits radiation comprises a light source that emits at least one light beam and wherein the at least one sensor that receives radiation from each of the at least two different paths comprises at least two light detectors for detecting light in at least two light paths.

3. The system of claim 1, wherein the sound function is an audio signal.

4. The system of claim 1, wherein the sound function is a tone signal.

5. The system of claim 1, wherein the controller comprises a central processing unit.

6. The system of claim 1, wherein the controller comprises a digital signal processor.

7. The system of claim 1, further comprising a sound source comprising a storage device for storing multiple tone waveform data, the multiple tone waveform data being readable for producing the sound function.

8. The system of claim 1, wherein the characteristic of the radiation comprises magnitude of radiation.

9. A method of controlling music based on the motion of an object within a specified spate, the method comprising:

receiving radiation reflected from an object within the specified space along at least two light paths;

generating information based on a characteristic of radiation received from each of the at least two light paths;

receiving performance data from a performance signal source;

generating an audio signal based on the performance data; and

controlling a characteristic of the audio signal based on the generated information.

10. A method as recited in claim 9, wherein receiving radiation reflected from an object comprises receiving light reflected from an object.

11. The method recited in claimed 9, wherein receiving performance data from a performance signal source comprises receiving performance data from a digital music signal source.

12. The method recited in claim 9, wherein receiving performance data from a performance signal source comprises re...

METHOD AND APPARATUS FOR PLAYING IN SYNCHRONISM WITH A DIGITAL AUDIO FILE AN AUTOMATED MUSICAL INSTRUMENT
2010-03-04
an automated piano in synchronism with a CD, the CD media contained music sequences that were pre-synchronized to a digital accompaniment music track encoded as linear PCM. For instance, the audio music track would be encoded as PCM on the left channel of the CD, and the music sequence, encoded as MIDI, would be encoded on the right channel. In the invention described herein, the system utilizes off the shelf commercially recorded CD, or other digital audio data such as MP3 files, and music sequences specifically authored to play in synchronism with the musical selections on the media. The music sequences are generally MIDI files stored on removable media such as SD cards and the like. One skilled in the art will recognize that there are many ways to deliver the music sequences, such as MIDI files, to the consumer and ultimately to the controller of the automated musical instrument, and SD cards are but one example. Likewise, the MP3 or other digital audio data can be stored in any number of media, including optical discs, hard drives, SD cards, Compact Flash cards or any other media suitable for storing digital data.

SUMMARY OF THE INVENTION

[0006] The system described herein includes a controller for delivering the music sequences to the automated musical instrument. The controller is also in communication with a drive or other device or software capable of playing or rendering digital media such as a CD, MP3 files, or other digital audio data. The controller, using the digital audio data as a time reference, delivers the music sequences to the automated musical instrument so that the instrument plays in synchronism with the selection playing from the digital audio data. One skilled in the art will recognize that the controller could also host and act as the player for the music sequence with the appropriate software. Hence, the controller can host and act as the player for both the digital audio data and the music sequence.

[0007] The following terms and definitions are used in this specification. The definitions included herein are to add meaning to terms and are not meant to limit or otherwise supplant meanings that are understood by those skilled in the art. [0008] MIDI--Acronym for Musical Instrument Digital Interface. MIDI is a music industry standard for digitally communicating musical instrument articulation events as a sequence of one or more bytes per event. The standard includes mechanical, electrical and byte signaling specifications. [0009] MIDI Interface--A physical interface across which MIDI bytes are sent and/or received. [0010] MIDI Event--A byte sequence that encodes a single musical instrument articulation event such as `key on` or `sustain pedal depressed.` [0011] MIDI Sequence--A chronological sequence of time-stamped MIDI events that encapsulates a performance of one or more musical instruments. [0012] MIDI Sequencer--A device that plays a MIDI Sequence in real time for the purpose of reproducing a musical performance. [0013] Standard MIDI File (SMF)--A music industry standard for storing and retrieving MIDI Sequences to and from a digital data file commonly referred to as MIDI file. [0014] Pianomation--A system for translating MIDI events to electro-mec...

High density sound enhancing components for stringed musical instruments
2010-03-03
a stone laminate. According to the disclosure of the patent, the stone employed may be extremely dense and hard, extremely soft(soapstone being an example), or anywhere in between in order to provide the desired effect. An extremely hard rock, for example, will give the musical instrument great sustain properties. A softer rock or stone, on the other hand, may be used toaffect the sound in other ways, such as "softening" the tone and resonance. The patent further discloses that when the stone laminate is positioned at the pick guard of an electric stringed instrument, the aural characteristics are affected due toshielding of the instrument's electronic components.

U.S. Pat. No. 5,097,514 for an Equilateral Tetrahedral Speaker discloses that the enclosure can be constructed of dense material such as a CORIAN鈩?material to minimize enclosure coloration. CORIAN鈩?is Dupont's registered trademark forits premium quality brand of solid surface product that is a solid, homogeneous, filled material containing methyl methacrylate.

U.S. Pat. No. 4,190,739 for High-Fidelity Stereo Sound System discloses that in an actual embodiment of a surface, marble gravel was glued across the surface of a parabolic surface like the parabolic surface of well-known microwave antennas.

U.S. Pat. No. 4,805,221 for the Construction of Sound Converter in Sound Guide Especially for Loudspeakers, for Example Speaker Boxes, discloses that the conventional technology for attaining this object consists in providing the sound guideand housing with sufficiently thick walls, adding braces and reinforcements, and/or selecting a material which has high internal clamping. Examples of this are speaker boxes made of concrete, marble, ceramic Plexiglas, and aluminum.

SUMMARY

According to a first broad aspect of the present invention, stone can be used as a resonating surface for an acoustical device, such as a musical instrument. With many such instruments, weight of the instrument is a critical factor. Forexample, musicians generally reject guitars that weigh over 8 or 9 pounds. Similar weight limitations apply to other string instruments, such as banjos, mandolins, violins, and the like. An instrument such as a piano generally does not have a weightlimitation from the standpoint of a performer but practical considerations limit the weight of pianos.

According to another broad aspect of the invention, it has now been found that although a material such as granite would not resonate in a manner comparable to wood, providing a stringed musical instrument with a thin acoustical veneer of stoneas a sound board, in conjunction with grounding and interconnecting, and having stone as the major sound-generating components of the instrument, dramatic acoustic benefits can be produced. The added stone enhancements are designed to connect andvibratically unify the soundboard, strings, bridge system, pickups, neck and body in a time-correct sound transfer loop.

According to a further broad aspect of the invention, it has now been found that the added stone enhancements collective mass and high-efficiency transmission rate focuses, retains and centralizes the instruments core vibrations producing abalanced, compressed, naturally equalized sound with remarkable clarity and sustain with minimal distortion. It should be understood, that when reference is made to a veneer, it is not intended to be inclusive of a mere thin, decorative layer, such astypically made from materials such as wood, metal, paper or plastics. The veneer must be of sufficient mass to function as an acoustic material. For an instrument like a guitar, a granite veneer is preferably in the range from about 1/8 to 11/16 of aninch.

According to still another broad aspect of the invention, connecting and vibratically unifying the soundboard, strings, bridge system, pickups, neck and body in a time-correct sound transfer loop, produces a balanced, compressed, and naturallyequalized sound, with remarkable clarity and sustain, and with minimal distortion.

In another aspect of the invention, the vibratical unification is produced through the use of high sound conductivity materials to acoustically interconnect the soundboard, strings, bridge system, pickups, neck, and body in a time-correct soundtransfer loop. The high sound conductivity material can be a mineral such as stone, in particular granite, ceramics, metals, and other high density solid...

Electronic music system and stringed instrument input device therefor
2010-03-02
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10. An electronic music system as defined in claim 7 further characterized by said means for applying a discrete fret voltage to each of said frets comprising a plurality of resistors connected in series with one another with each of saidresistors being electrically connected between a respective pair of said frets and means for providing a constant valued flow of current through said resistors.

11. An electronic music system as defined in claim 10 further characterized by said means for providing a constant valued flow of current being arranged so that said current flows in the direction from the highest tone valued one of said fretsto the lowest tone valued one of said frets whereby said highest tone valued fret has the highest discrete fret voltage applied to it.

12. A means for providing voltage signals for driving a voltage controlled tone generator in an electronic music producing system, said means comprising: a stringed musical instrument having a plurality of spaced parallel strings located over afret board having a plurality of frets extending transversely of said strings and spaced from one another along the length of said fret board with each string-fret pair representing an assigned musical tone, and means responsive to any one of saidstrings being pressed into contact with any one of said frets for producing a voltage signal having a voltage value analogously related to the frequency of the musical tone assigned to the contacting string-fret pair.

13. A means for providing voltage signals for driving a voltage controlled tone generator in an electronic music producing system said means comprising: a stringed instrument having a plurality of spaced parallel electrically conductive stringslocated over a fret board having a plurality of electrically conductive frets extending transversely of said strings and spaced from one another along the length of said fret board, with each string-fret pair representing an assigned musical tone, meansfor applying an electric voltage to each of said frets with each of said frets having a voltage different from that applied to the other of said frets, an offset voltage source providing a plurality of offset voltages each assigned to a respective one ofsaid strings with each of said offset voltages being different from the other of said offset voltages, and means responsive to any one of said strings being pressed into contact with any one of said frets for adding the voltage appearing on said one fretto the offset voltage assigned to said one string to produce an output signal, said fret voltage and said offset voltage being so selected that said output signal has a voltage value analogously related to the frequency of the musical tone represented bythe contacting string-fret pair.DescriptionBACKGROUND OF THE INVENTION

This invention relates to electronic music producing systems having a voltage controlled tone generator or synthesizer, for sequentially producing electrical audio frequency signals, for driving a loud speaker or other electro-acousticaltransducer, having fundamental frequencies controlled in accordance with the values of input voltage signals, and deals more particularly with a device for producing such input voltage signals which device is generally in the form of a guitar or otherfretted stringed instrument.

Electronic music systems having voltage controlled tone generators or synthesizers are well known in the art. The tone generator of such a system usually includes a large number of manually adjustable controls for varying various tonecharacteristics, such as timbre, attack, decay, vibrato, tremolo, etc. to obtain different sounds or effects. However, the basic sequence of the tones and their timing is usually controlled manually through a generally conventional keyboard played in agenerally conventional manner. Thus, persons performing on presently known synthesizer systems should be relatively skilled keyboard instrument players, and such systems are of limited usefulness to musicians skilled pr...

Generation of noise-like tones in an electronic musical instrument
2010-02-27
AbstractAn electronic tone synthesizer in which a master data list of digital values representing the amplitudes of points defining the waveform of a musical tone are transferred to a digital-to-analog converter at a rate proportional to the pitch of the tone being generated. Noise is superimposed on the musical tone by means of a random binary signal generator which controls a circuit for modifying selected ones of the digital values as they are transferred from the master data list to the converter. Modification of the selected values may be by a right shift operation, a 2's complement operation, or by selective delay.ClaimsWhat is claimed is: 1. An electronic tone synthesizer for generating an audio signal having a predetermined waveform in which noise is superimposed on the audio signal, comprising: a group ofdigital words representing the relative amplitudes of equally spaced points defining the waveform of an audio signal, a digital-to-analog converter, means transferring the digital words sequentially from the generating means and applying the words inrepetitive sequence to the converter, the transferring means including means for modifying the digital value of any selected word as it is being transferred, a random signal generator for generating an output signal at random time intervals, and meansresponsive to the random output signal for momentarily activating said means for modifying a word being transferred, whereby the digital words are modified at random during transfer. 2. Apparatus of claim 1 wherein said means for modifying said digital values includes a right shift circuit for shifting the digital values of the randomly selected words numerically at least one place to the right. 3. Apparatus of claim 1 wherein said means for modifying said digital values includes a 2's complement circuit for generating the 2's complement of the digital values of the randomly selected words. 4. Apparatus of claim 1 wherein said means for modifying said digital values includes means for delaying the time of transfer at which a selected word is transferred from the generating means. 5. Apparatus of claim 2 wherein the transferring means further includes a shift register, a right shift circuit for transferring each of the digital words in sequence from the generating means to the shift register, clock means for generatingclock signals at a rate proportional to the pitch frequency of the tone being generated, said transferring means being activated by said clock signals. 6. Apparatus of claim 3 wherein the transferring means includes a shift register, a 2's complement circuit for transferring each of the digital words from the generating means to the shift register, clock means for generating clock signals at arate proportional to the pitch frequency of the tone being generated, said transferring means being activated by said clock signals. 7. In an electronic tone synthesizer in which a master data list of digital values representing the amplitude of points defining the waveform of a musical tone are transferred to a digital-to-analog converter at a rate proportional to the pitchof the tone being generated, apparatus for superimposing noise on the tone comprising: an addressable memory for storing the master data list, a shift register receiving the output of the memory, clock means for generating clock pulses at said rateproportional to the pitch of the tone being generated, the clock means shifting said register, random address generating means for selectively transferring words from any one of a plurality of locations in the master data list memory to the shiftregister with each clock pulse, and means transferring the words in the shift register to said converter to convert said words to an analog voltage whose amplitude is controlled by the digital values of said words stored in the shift register. 8. A tone synthesizer comprising source means providing a group of words representing respectively the amplitudes of equally spaced points defining the waveform of a musical tone, digital-to-analog converter, means transferring said group ofwords in timed sequence from the source means and applying the words to the converter, and a random signal generator for generating timing pulses at random time intervals, said transferring means including means responsive to the timing pulses from saidrandom signal generator for modifying the values of those digital words transferred in time coincidence with the pulses from the random signal generator.DescriptionFIELD OF THE INVENTION This invention relates to musical tone synthesizers, and more particularly, to a noise generator for a digital tone generator. BACKGROUND OF THE INVENTION The generation of musical tones electronically, either by analog or digital circuits, is well known. In attempting to duplicate the sounds of conventional musical instruments it may be desirable to superimpose sounds which can only becharacterized as "noise" onto the musical tones. Such added noise may be introduced to simulate the air noise, hiss, or breathiness characteristic of wind-operated instruments, such as the organ pipes of a conventional organ, or other types of windinstruments. In prior art digital type organs tones have been created imitative to noisy wind-blown organ pipes, by using a frequency modulation technique. This has been accomplished by adding or subtracting a fixed constant to the frequency numberused to address the tone data. Alternatively, the noise has been added to the reference voltage of the analog output signal from the digital-to-analog converter to produce an amplitude modulated noise. Noiselike tones have been created in digital tonegenerators by the type which calculate musical waveshapes by computation with an algorithm that uses sets of harmonic coefficients. However, the resulting tonal effect is not easily controlled. If the harmonic coefficients are varied in a randomfashion, noise having a very wide spectrum is produced and has the effect of substantially obliterating the basic musical tone being generated. SUMMARY OF THE INVENTION In copending application Ser. No. 603,776, filed Aug. 11, 1975, entitled "Polyphonic Tone Synthesizer", now issued as U.S. Pat. No. 4,085,644 there is described a digital tone generator in which a master data list is calculated and stored ina main register. The master data list consists of a series of digital values representing the amplitudes of a corresponding series of points defining the waveform of one cycle (or fraction of a cycle) of a musical tone. The master data list istransferred from the main register to a Note shift register and from the Note register to a digital-to-analog converter at a rate determined by the pitch or fundamental frequency of the tone being generated. Because the ...

Electronic musical instrument with exponential keyboard and voltage controlled oscillator
2010-02-26
both on which of saidswitches is operated and on the selected potential, and selector means for selecting one of a plurality of potentials for application to said series circuit.

7. Apparatus according to claim 6, wherein said selector means comprises means for selecting one of a plurality of discrete voltage levels for application to said series circuit, said discrete voltage levels differing from each other by factorswhich are powers of two, whereby the frequency of said sound signal falls with in an octave selected by said selector means.

8. Apparatus according to claim 6, including means for producing an a.c. signal, means for coupling said a.c. signal to said voltage divider, and detector means connected with said control voltage for developing a signal in response to detectionof said a.c. signal following depression of one of said keys.

9. An electronic musical instrument having a first voltage controlled oscillator for producing a sound signal having a frequency proportional to a control voltage applied to it, a keyboard having a plurality of keys, a plurality of switches, onefor each of said keys, each adapted to be operated by depression of its associated key, a voltage divider connected with said switches for connecting a control voltage to said oscillator which corresponds to the position of the key associated with anoperated one of said switches, said voltage divider comprising a plurality of resistance elements connected in series, each having resistance values which bear an exponential relation to the resistance values of adjacent connected resistors, such thatthe voltage at successive junctions of said resistance elements corresponds to a geometric series, a second voltage controlled oscillator, and tuning means for connecting said control voltage to said second oscillator, said tuning means being operativeto modify said control voltage whereby said second oscillator oscillates at a frequency which differs from the frequency of the first oscillator by a constant factor.

10. Apparatus according to claim 9, wherein said tuning means includes manually adjustable means for selecting a predetermined relationship between the frequencies of said first and second oscillators.DescriptionBACKGROUND

1. Field of the Invention

The present invention relates to electronic musical instruments, and more particularly to the class of such instruments known as synthesizers.

2. The Prior Art

Electronic music synthesizers generally include an oscillator with means for selectively controlling the frequency produced by the oscillator, so that the output of the oscillator may be caused to produce musical tones and sounds. One componentof a synthesizer is a tunable oscillator, and it is important that the oscillator remain in tune, without varying as a result of changes in temperature and other environmental conditions. If the oscillator does not inherently have the requiredstability, it must frequently be retuned, which is an inconvenience. In addition, rapid changes in tune (e.g., during warming up) are musically unsatisfactory.

In one class of synthesizers, a voltage divider is employed with several taps which are selected individually in accordance with the frequency of the signal which is desired to be produced by the oscillator. It is conventional to construct sucha voltage divider by connecting in series several components which all have the same resistance, so that an equal voltage difference is developed by each change in the position of a selected tap, connected to the junction of adjacent components. It isnecessary to use an oscillator arrangement which produces a frequency which is an exponential function of the control voltage, so that twelve successive taps produce the frequencies corresponding to the various notes of one octave of the musical scale.

Several designs for oscillators which have the required exponential function have been developed. In one such design, the oscillator is provided with a function generator for developing an exponential function in response to a linear inputvoltage, and a linear oscillator is controlled by the output of the functi...