US3794748A
Expired / Lapsed
US
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Apparatus and method for frequency modulation for sampled amplitude signal generating system
Assignee: Boeing North American Inc
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Filing: 1971-12-06
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Granted: 1974-02-26
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Expires: 1991-12-06
Abstract
Abstract A memory contains data in a plurality of discrete locations and is addressed at a rate that depends upon desired spacing between data from various locations as it is sequentially read from the memory. In a specific embodiment the data constitutes amplitude values of a complex wave form of a type produced by a musical instrument at equally spaced points in time along an axis of the wave form. The memory is addressed at any one of a plurality of rates selected in accordance with a musical note to be played. Selection of a particular note results in a repetitive read out from the memory of groups of amplitude samples that collectively represent a wave shape. The group repetition rate represents the frequency of the desired musical tone and is determined by a control number that is unique for each output frequency. The control number periodically increases a number stored in the memory address register by the value of the control number so as to identify appropriate data addresses in the memory. Having selected a unique control number and therefore a unique output signal frequency, the latter is modulated by changing the control number during the repetitive generation of groups of amplitude samples. The same magnitude of small change in the control number for a plurality of frequencies to be generated will achieve an ensemble effect for octave decoupling. A relatively small magnitude repetitive variation of the control number, as groups of amplitude samples are repetitively read from the memory, will provide a tremulant effect. Other types of variation of the control number will achieve other types of frequency modulation.
Inventors
- 👤 R Deutsch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:26
CPC Classifications
G; G10; G10H; G10H1/00; G10H1/02; G10H1/04; G10H7/00; G10H7/02; G10H7/06; Y; Y10; Y10S; Y10S84/00; Y10S84/04
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
120 words
The method of changing first and second notes that have nominal frequencies of different steps in a musical scale comprising the steps of generating a first digital control signal having a magnitude that directly controls frequency of a first note in said musical scale to be generated thereby, generating said first note from said first digital control signal, generating a second digital control signal having a magnitude that directly controls the frequency of a second note in said musical scale to be generated thereby, generating a second note from said second digital control signal, and changing at least one of said digital control signals so as to effect a relatively small change in the frequency of the note generated thereby.
Claim 2
Independent Claim
120 words
The method of changing first and second notes that have nominal frequencies of different steps in a musical scale comprising the steps of generating a first digital control signal having a magnitude that directly controls frequency of a first note in said musical scale to be generated thereby, generating said first note from said first digital control signal, generating a second digital control signal having a magnitude that directly controls the frequency of a second note in said musical scale to be generated thereby, generating a second note from said second digital control signal, and changing at least one of said digital control signals so as to effect a relatively small change in the frequency of the note generated thereby.
Claim 3
Dependent Claim
45 words
The method of claim 1 wherein said first and second notes are corresponding notes of different octaves, and wherein both of said control signals are changed in substantially the same way so as to introduce a small beat frequency into the combination of said notes.
Claim 4
Dependent Claim
27 words
The method of claim 1 wherein each said control signal is a digital representation having a nominal magnitude that is uniquely related to an individual note frequency.
Claim 5
Dependent Claim
60 words
The method of claim 1 wherein each said control signal is a representation of a magnitude selected from a set of magnitudes each of which is uniquely related to a different step in said musical scale, and wherein said step of changing one of said control signals comprises changing said representations to magnitudes not contained within said set of magnitudes.
Claim 6
Dependent Claim
47 words
The method of claim 2 wherein said step of changing at least one of said control signals comprises the step of changing both of said control signals by the same amount whereby the frequencies of said first and second notes are both changed by the same amount.
Claim 7
Dependent Claim
124 words
A frequency modulation system for an electrical musical instrument comprising means for generating a frequency control signal having a parameter directly related to frequency of a musical signal to be generated therefrom, means responsive to said frequency control signal for generating repetitive groups of amplitude sample representations collectively delineating a wave shape of a musical note, the repetition rate of said groups being directly controlled by said control signal, means for selecting a value of said parameter that uniquely defines a desired nominal frequency of a musical note, modulating means for changing the selected value of said control signal parameter, and means for converting said groups of amplitude sample representations to a musical signal of said nominal frequency as modulated by said modulating means.
Claim 8
Dependent Claim
124 words
A frequency modulation system for an electrical musical instrument comprising means for generating a frequency control signal having a parameter directly related to frequency of a musical signal to be generated therefrom, means responsive to said frequency control signal for generating repetitive groups of amplitude sample representations collectively delineating a wave shape of a musical note, the repetition rate of said groups being directly controlled by said control signal, means for selecting a value of said parameter that uniquely defines a desired nominal frequency of a musical note, modulating means for changing the selected value of said control signal parameter, and means for converting said groups of amplitude sample representations to a musical signal of said nominal frequency as modulated by said modulating means.
Claim 9
Dependent Claim
82 words
The system of claim 6 wherein said control signal is a digital representation of a number selected from a set of numbers, wherein said means for generating groups of amplitude sample representations comprises an address register, a control number register, and means for repetitively advancing the address register by the number in the control number register, and wherein said modulating mEans comprises means for changing the number in said control number register to a number not contained in said set of numbers.
Claim 10
Dependent Claim
109 words
The frequency modulation system of claim 6 wherein said means for generating groups of amplitude sample representations comprises a memory storing representations that collectively delineate such wave shape and addressing means for reading out said stored representations at a group repetition rate that defines the nominal frequency of a wave shape to be generated, wherein said means for generating a frequency control signal comprises a number storage device and means for introducing into said number storage device a number that identifies a nominal musical signal to be generated, and wherein said modulating means comprises means for changing at least one digit of said number in said number storage device.
Claim 11
Dependent Claim
50 words
The frequency modulation system of claim 8 wherein said modulating means comprises means for changing the digit of a single order of the number in said number storage device by a selected amount for any one of a plurality of numbers that may be contained in said number storage device.
Claim 12
Dependent Claim
167 words
A musical tone generation system comprising a memory containing representations of sampled amplitudes of a wave form of a musical note, memory address means for repetitively reading said representations from said memory to provide an output comprising repetitive groups of said representations, said groups having repetition rate corresponding to the frequency of the musical tone to the frequency of the musical tone to be generated thereby, a number storage device and means for repetitively augmenting said memory address means by the amount of the number stored in said number storage device, thereby to control the repetition rate of groups of representations read from said memory, means for selecting the frequency of a note to be generated, means responsive to said note frequency selecting means for introducing into said number storage device a number selected from a set of numbers that represent notes of a musical scale, and frequency modulation means for changing the number in said number storage device as representations are being read from said memory.
Claim 13
Dependent Claim
167 words
A musical tone generation system comprising a memory containing representations of sampled amplitudes of a wave form of a musical note, memory address means for repetitively reading said representations from said memory to provide an output comprising repetitive groups of said representations, said groups having repetition rate corresponding to the frequency of the musical tone to the frequency of the musical tone to be generated thereby, a number storage device and means for repetitively augmenting said memory address means by the amount of the number stored in said number storage device, thereby to control the repetition rate of groups of representations read from said memory, means for selecting the frequency of a note to be generated, means responsive to said note frequency selecting means for introducing into said number storage device a number selected from a set of numbers that represent notes of a musical scale, and frequency modulation means for changing the number in said number storage device as representations are being read from said memory.
Claim 14
Dependent Claim
28 words
The tone generation system of claim 10 wherein said frequency modulation means comprises means for changing the digit stored in a preselected order of said number storage device.
Claim 15
Dependent Claim
132 words
In a musical tone generation system comprising a memory containing representations of sampled amplitudes of a wave form of a musical note, memory address register means for repetitively reading said representations from said memory to provide an output comprising repetitive groups of said representations, said groups having a repetition rate corresponding to the frequency of the musical tone to be generated thereby, address rate control means for controlling said address register to thereby control the read out repetition rate of said groups read from said storage memory, and manually selectable means for controlling said address rate control means so as to select a desired musical tone of a musical scale, the improvement comprising means for modulating said address rate control means so as to modulate the frequency of the selected musical tone.
Claim 16
Dependent Claim
132 words
In a musical tone generation system comprising a memory containing representations of sampled amplitudes of a wave form of a musical note, memory address register means for repetitively reading said representations from said memory to provide an output comprising repetitive groups of said representations, said groups having a repetition rate corresponding to the frequency of the musical tone to be generated thereby, address rate control means for controlling said address register to thereby control the read out repetition rate of said groups read from said storage memory, and manually selectable means for controlling said address rate control means so as to select a desired musical tone of a musical scale, the improvement comprising means for modulating said address rate control means so as to modulate the frequency of the selected musical tone.
Claim 17
Dependent Claim
38 words
The system of claim 12 wherein said address rate control means is a number storage register, and wherein said modulating means comprises means for changing the digit in one order of low significance of said number storage register.
References Cited (Backward Citations)
US2905905A
Cited
US3007361A
Cited
US2989887A
Cited
US3157725A
Cited
US3288907A
Cited
US3288904A
Cited
US3474182A
Cited
US3490327A
Cited
US3515792A
Cited
US3515792B1
Cited
US3516318A
Cited
US3610799A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-25 | 1977-08-27 | 1978-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-25 | 1981-08-27 | 1982-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-25 | 1985-08-27 | 1986-02-26 | $7700.00 | Window Closed / Lapsed |