US3479440A - Randomly-perturbed,locked-wave generator - Google Patents
Randomly-perturbed,locked-wave generator Download PDFInfo
- Publication number
- US3479440A US3479440A US572481A US3479440DA US3479440A US 3479440 A US3479440 A US 3479440A US 572481 A US572481 A US 572481A US 3479440D A US3479440D A US 3479440DA US 3479440 A US3479440 A US 3479440A
- Authority
- US
- United States
- Prior art keywords
- frequency
- voltage
- stages
- sawtooth
- chain
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
- G10H1/00—Details of electrophonic musical instruments
- G10H1/02—Means for controlling the tone frequencies, e.g. attack or decay; Means for producing special musical effects, e.g. vibratos or glissandos
- G10H1/04—Means for controlling the tone frequencies, e.g. attack or decay; Means for producing special musical effects, e.g. vibratos or glissandos by additional modulation
- G10H1/043—Continuous modulation
Definitions
- a tone generator for an electronic organ employing frequency divider chains for generating octavely related tones, in which each stage of a divider chain is perturbed independently of the others on a per cycle basis while maintaining an average locked synchronism among the frequency divider stages of the divider chain.
- the present invention relates generally to electronic organ tone generators, and more particularly to chains of frequency dividers which have provision for perturbing the dividers in uncorrelated fashion inter se.
- organ pipe tone is inherently less stable than typical electronic organ tone generators and particularly that organ pipe tone is inherently less stable than electronic organ tone which derives from frequency divider chains. It is considered desirable to generate electronic organ tones which simulate as closely as possible the tones of organ pipes.
- the solution to the problem of providing a frequency divider chain in which the stages are perturbed in uncorrelated fashion is to trigger the successive stages of the frequency divider along the gradually rising portions of the sawteeth rather than in respons to the rapidly sloping portions thereof, as is typically done in hard synch sawtooth divider circuits.
- Slope of the sawtooth wave is not really infinite in the vertical part of the sawtooth wave; but it is so steep typically that perturbation is ineffective along the time or phase axis.
- a single noise source can be used on all perturbation inputs, and the desirably uncorrelated modulation among the several stages can be obtained lbecause the trigger firing ⁇ of the separate stages is occurring at different times, when the random voltage is ditferent.
- Uncorrelated randomness can be obtained by using a noisy power supply for the frequency divider chain as a whole.
- the amount of randomness can be adjusted for each divider and the separate dividers can be completely uncorrelated, by adding noise signal through separate resistances to the several stages, the power supply itself being conventional.
- the random modulation of the several stages of the divider chain can be accomplished without the loss of the very important advantage, from the standpoint of tuning an electronic organ, of having locked octaves in a frequency divided chain.
- the octaves will never be out of tune with each other on an average basis, but as long as the perturbing signals are applied, the octaves will seldom for long be precisely in tune with each other.
- the further advantage is obtained that if, for example, one wishes to have a bland tonal effect produced, or a tonal variety or expression which involves no randomness, it can be obtained instantaneously by simply switching off the random modulation. For example, if in an organ system a generator is to serve multiple duty, there can be switches which turn off the perturbation, or turn on a barely perceptible amount, or increase it to an optimum amount, or even to introduce an unnatural amount for special effects in highly descriptive music.
- frequency (vibrato) modulate all the stages of a frequency divider chain rather than to randomly modulate, or to combine the two effects.
- random modulation can be achieved by utilizing either a conventional DC power supply supplemented by noise, or by utilizing a noise supply as the only power source.
- FIGURE 1 is a schematic circiut diagram of a preferred embodiment of the invention.
- FIGURE 2 is a block diagram of a modification of the system of FIGURE l.
- 10 is a saturation iip-op, of conventional character per se, which acts as the master oscillator or synch source of the present system.
- An output of Hip-flop 10 is integrated in integrator 10a and then applied via lead 11 to the base of an NPN transistor T1, having its emitter connected through a small resistance 12 to a ground lead 13.
- the collector of T1 is coupled by a capacitor C11 to a +15 v.
- ⁇ bus 14 and ground bus 13 Connected between ⁇ bus 14 and ground bus 13 is a resistance 16 and a unijunction transistor T2.
- the junction 17 of resistance 16 and transistor T2 is connected by diode D1 to the collector of T1, diode cathode to collector.
- a timing circuit consisting of resistance R1 and capacitor C1 in series is connected between leads 14 and 13, and the junction 18 of R1 and C1 is coupled to the control electrode or emitter of the unijunction transistor T2 and to the base of an emitter follower NPN transistor T3.
- the circuit 20 is an exemplary noise generator, including an NPN transistor T4, having a grounded emitter, a collector connected via resistances 21 and 21a to supply voltage bus 14, and a bias connection including a resistance 22 connected from collector to base.
- Capacitors 23, 24 and 32, 33 control the spectrum of the noise signal.
- Switch 25 is used to vary the modulation spectrum. The,
- transistor T4 is selected to be noisy.
- the noise signal provided by T4 is coupled to NPN transistor T5, having circuitry duplicating that ofT 4, and which, although a noise generator in itself, acts principally to amplify the noise output of T4.
- Transistor T6 amplies the signal at the collector o-f T5, and is provided with a collector load in the form of resistance divider 28. Coupling between T4 and T5 as well as between T5 and T6 consists of a large capacitor C20, which acts as a highpass lter and a DC-blocking capacitor.
- a desired level of noise signal (riding on DC) is provided to a perturbation bus 34, which distributes the noise signal to the several stages of the divider chain, generally indicated at D, and which may have as many stages as required by a given electronic organ, for which it constitutes a tone generator.
- the saturation flip flop provides a square wave voltage at point a which varies between zero and the voltage set by the reference diode.
- the integrating action of resistor 29 and capacitor C26 converts the square wave to a semi-triangular wave.
- the voltage applied to the base of T1 is therefore approximately triangular.
- the construction of the unijunction transistor is well known.
- Two ohmic contacts B1 and B2 are made at opposite ends of a small bar of n-type silicon semiconductor.
- a single rectifying contact, called the emitter E is made on the opposite side of the bar close to B2.
- An interface resistance then exists between B1 and B2.
- B1 is grounded and a positive voltage applied to B2. With no emitter current flowing, the silicon bar acts as a voltage divider with respect to the emitter, a certain fraction Ve of the positive voltage appearing at the emitter. If the externally applied emitter voltage is less than Ve the emitter will be reverse biased, but if the externally applied voltage is greater than Ve the emitter will be forward biased and current will ow.
- the emitter to B1 circuit of the transistor has a negative resistance characteristic, so that a rapid increase of current occurs.
- the circuit containing transistors T1, T2, and T3 converts the semi-triangular wave, at the base input of T1, to a sawtooth wave at the emitter output of T3 without changing the average frequency, although the instantaneous frequency can be changed by the perturbation voltage.
- the sawtooth appearing at the base of T3 is transferred by emitter follows action to the emitter of T3 with no phase inversion and by amplifier action, with gain less than one, to the collector of T3, wtih phase inversion.
- the sawtooth wave at the emitter of T3 is transferred to the output terminal through the decoupling resistor 31.
- the inverted sawtooth at the collector of T3, combined Iwith the perturbation voltage, serves as the synchronizing signal for the following unijunction transistor T9.
- the time constants have been set so that the unijunction transistor breaks down on every second sawtooth appearing at its base 2 terminal, thus producing a frequency division of two at each successive output.
- the noise signal on perturbation bus 34 is applied -to the base B2 of the unijunction transistors T2, T9, etc., correspondingly in all stages of the divider chain.
- the sawtooth frequency divider of the present invention is of a type known as soft synch, to be distinguished from hard synch, which has previously been exclusively employed in tone generators for electronic organs.
- the hard synch divider employs the vertical slopes of wave forms generated by preceding stages to trigger succeeding stages.
- the soft synch chains utilize the attainment of a voltage level along the slow rise ⁇ time slopes of wave forms generated by preceding stages to trigger succeeding stages.
- perturbations should not be taken to exclude sinusoidal or complex periodic voltages, so that the present invention can be used to produce vibrato, with a single vibrato oscillator, say at 7 c.p.s. phase modulating each of the stages 0f a divider chain to a different degree.
- a single vibrato oscillator say at 7 c.p.s. phase modulating each of the stages 0f a divider chain to a different degree.
- an interesting effect can be achieved by combining vibrato signal and noise signal, as the perturbation.
- a vibrato source 40 may be connected to perturbation bus 30, or both noise and vilbrato may be so connected, by manipulation of switches 4 42.
- Conventional frequency dividers employed in organ tone generators have division ratios of two per stage.
- the divider of the present invention can provide -any reasonable integral division ratio, i.e. 2, 3, 4, 5, etc., and such division ratios are nding utility in electronic organs.
- a steady DC voltage bus is provided, and also a perturbation bus. It is feasible however, so long as a soft synch divider chain is employed, to utilize a noise source, or noise plus DC, as a sole voltage supply for the chain, and to accomplish the results of the invention, i.e., to have locked synchronism on average for the chain but to perturb all stages of the chain in uncorrelated fashion, on a short term basis.
- the frequency divider chain 50 may be, in detail, the system of FIGURE 1, except in that the noise source 20 may be alone utilized as a voltage supply for the chain.
- a vibrato source 52 may superpose its output on the noise supply 20.
- the stages of divider chain 50 may provide output, as at 53, 54, 55, 56, 57, -to key switches 58, and the latter may supply tones, when actuated, to tone color filters 59, ⁇ 60, for amplification by arnplifier-61 and radiation by loudspeaker 62.
- a tone generator comprising a frequency divider chain, said frequency divider chain including frequency dividers connected in cascade,
- each of said frequency dividers being arranged to generate sawtooth waveforms
- each of said sawtooth waveforms having a slowly varying portion joined with a rapid return portion
- said last means being responsive only to a slowly varying portion of the waveform produced by a preceding one of said frequency dividers for initiating the return portion of a succeeding frequency divider connected in cascade with said preceding one of said frequency dividers.
- said last means is a means for separately and diiferently perturbing a plurality of said slowly varying portions.
- said means for perturbing includes a single noise generator, and means for applying the output of said noise generator concurrently to all said frequency dividers.
- said soft synchronized sawtooth oscillator providing a wave having a slow rise and a rapid return
- said sawtooth oscillator including means responsive only to a predetermined level of said periodic sawtooth waveform for effecting a transition from its slow rise to its rapid return.
- tone generator said tone generator comprising a cascaded sequence of soft synchronized frequency dividers
- said means for individually perturbing comprises a single noise source connected to said frequency dividers.
- said means for individually perturbing comprises a single vibrato signal source connected to said frequency ⁇ di viders.
- said means for individually perturbing includes both a single noise source and a vibrato signal source, and means for selectively connecting one or -both of said noise source and vibrato signal to said frequency dividers.
- each of said dividers including a two state device having two primary electrodes and a control electrode
- RC circuits connected between the control electrodes and a primary electrode of each of said two state devices for generating sawtooth voltages at said control electrodes
- said two state devices being arranged to fire on attachment of a predetermined amplitude relation between the voltage across said primary electrodes and between said primary electrode and said control electrode, and
- v said two state devices are solid state switching devices.
- a tone generator comprising a frequency divider chain, including frequency dividers connected in cascade,
- each of said dividers including a triggering device having two states and including two primary electrodes and a control electrode,
- said triggering device is a unijunction transistor.
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Electrophonic Musical Instruments (AREA)
Description
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US57248166A | 1966-08-15 | 1966-08-15 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3479440A true US3479440A (en) | 1969-11-18 |
Family
ID=24288010
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US572481A Expired - Lifetime US3479440A (en) | 1966-08-15 | 1966-08-15 | Randomly-perturbed,locked-wave generator |
Country Status (1)
Country | Link |
---|---|
US (1) | US3479440A (en) |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3711620A (en) * | 1970-01-29 | 1973-01-16 | Tokyo Shibaura Electric Co | Musical tone signal generator |
US3735013A (en) * | 1970-09-22 | 1973-05-22 | Philips Corp | System for producing an aperiodic vibrato signal |
US3740449A (en) * | 1971-06-24 | 1973-06-19 | Conn C Ltd | Electric organ with chord playing and rhythm systems |
US3754495A (en) * | 1970-10-27 | 1973-08-28 | M Honegger | Sounding note board for music instruction |
US3824326A (en) * | 1972-06-09 | 1974-07-16 | Kawai Musical Instr Mfg Co | Vibrato signal generating apparatus for an electronic musical instrument |
US3833752A (en) * | 1972-03-03 | 1974-09-03 | Eminent Nv | Electronic musical instrument with plural channels providing different phase shift |
US3847050A (en) * | 1970-08-26 | 1974-11-12 | Audio Synthesisers Ltd | Electronic organ with plural master oscillators and plural vibrato oscillators for each note |
US3867862A (en) * | 1973-06-11 | 1975-02-25 | Baldwin Co D H | Electrical musical instrument |
US3881387A (en) * | 1973-02-19 | 1975-05-06 | Nippon Musical Instruments Mfg | Electronic musical instrument with effect control dependent on expression and keyboard manipulation |
US3888153A (en) * | 1973-06-28 | 1975-06-10 | Nippon Gakki Seiko Kk | Anharmonic overtone generation in a computor organ |
US3948139A (en) * | 1974-08-28 | 1976-04-06 | Warwick Electronics Inc. | Electronic synthesizer with variable/preset voice control |
US3973463A (en) * | 1974-03-04 | 1976-08-10 | Hammond Corporation | Delayed vibrato and burble circuit |
US4276802A (en) * | 1978-04-03 | 1981-07-07 | Keio Giken Kogyo Kabushiki Kaisha | Electronic keyboard instrument |
US4348931A (en) * | 1980-04-21 | 1982-09-14 | Baldwin Piano & Organ Company | Simulating wind noise in electronic organs using digital noise generators |
US4384505A (en) * | 1980-06-24 | 1983-05-24 | Baldwin Piano & Organ Company | Chorus generator system |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2128367A (en) * | 1935-12-11 | 1938-08-30 | Baldwin Co | Electrical musical instrument of the type employing gaseous discharge tubes |
US2783381A (en) * | 1954-07-06 | 1957-02-26 | Estey Organ Corp | Frequency divider circuit for musical instruments |
US3114114A (en) * | 1960-11-09 | 1963-12-10 | Robert R Atherton | Voltage controlled ramp and pulse generator |
US3383549A (en) * | 1964-10-09 | 1968-05-14 | Norman P. Huffnagle | Sawtooth signal generator |
-
1966
- 1966-08-15 US US572481A patent/US3479440A/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2128367A (en) * | 1935-12-11 | 1938-08-30 | Baldwin Co | Electrical musical instrument of the type employing gaseous discharge tubes |
US2783381A (en) * | 1954-07-06 | 1957-02-26 | Estey Organ Corp | Frequency divider circuit for musical instruments |
US3114114A (en) * | 1960-11-09 | 1963-12-10 | Robert R Atherton | Voltage controlled ramp and pulse generator |
US3383549A (en) * | 1964-10-09 | 1968-05-14 | Norman P. Huffnagle | Sawtooth signal generator |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3711620A (en) * | 1970-01-29 | 1973-01-16 | Tokyo Shibaura Electric Co | Musical tone signal generator |
US3847050A (en) * | 1970-08-26 | 1974-11-12 | Audio Synthesisers Ltd | Electronic organ with plural master oscillators and plural vibrato oscillators for each note |
US3735013A (en) * | 1970-09-22 | 1973-05-22 | Philips Corp | System for producing an aperiodic vibrato signal |
US3754495A (en) * | 1970-10-27 | 1973-08-28 | M Honegger | Sounding note board for music instruction |
US3740449A (en) * | 1971-06-24 | 1973-06-19 | Conn C Ltd | Electric organ with chord playing and rhythm systems |
US3833752A (en) * | 1972-03-03 | 1974-09-03 | Eminent Nv | Electronic musical instrument with plural channels providing different phase shift |
US3824326A (en) * | 1972-06-09 | 1974-07-16 | Kawai Musical Instr Mfg Co | Vibrato signal generating apparatus for an electronic musical instrument |
US3881387A (en) * | 1973-02-19 | 1975-05-06 | Nippon Musical Instruments Mfg | Electronic musical instrument with effect control dependent on expression and keyboard manipulation |
US3867862A (en) * | 1973-06-11 | 1975-02-25 | Baldwin Co D H | Electrical musical instrument |
US3888153A (en) * | 1973-06-28 | 1975-06-10 | Nippon Gakki Seiko Kk | Anharmonic overtone generation in a computor organ |
US3973463A (en) * | 1974-03-04 | 1976-08-10 | Hammond Corporation | Delayed vibrato and burble circuit |
US3948139A (en) * | 1974-08-28 | 1976-04-06 | Warwick Electronics Inc. | Electronic synthesizer with variable/preset voice control |
US4276802A (en) * | 1978-04-03 | 1981-07-07 | Keio Giken Kogyo Kabushiki Kaisha | Electronic keyboard instrument |
US4348931A (en) * | 1980-04-21 | 1982-09-14 | Baldwin Piano & Organ Company | Simulating wind noise in electronic organs using digital noise generators |
US4384505A (en) * | 1980-06-24 | 1983-05-24 | Baldwin Piano & Organ Company | Chorus generator system |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US3479440A (en) | Randomly-perturbed,locked-wave generator | |
US3842702A (en) | Electronic musical instrument with variable frequency division | |
US3476864A (en) | Electronic organ reiteration system utilizing a zero-crossing preference circuit | |
US4001816A (en) | Electronic chime | |
US3659031A (en) | Monophonic electronic musical instrument with a variable frequency oscillator employing positive feed back | |
US3283057A (en) | Keyboard oscillator circuit | |
US3549774A (en) | Rhythmic accompaniment system employing an asynchronous chain of delay circuits | |
US3469109A (en) | Musical instrument frequency divider which divides by two and by four | |
US3478633A (en) | Counter resetting arrangement for rhythm accompaniment starting | |
US3535429A (en) | Integrated circuit switching device for electronic musical instruments | |
US3209279A (en) | Semiconductor noise source | |
US3499092A (en) | Accompaniment chord rhythm system | |
US3291886A (en) | Transient tone signal circuits | |
US3211926A (en) | Monostable multivibrator with variable pulse width | |
US3525796A (en) | Electronic musical instrument provided with generators and individual formant filters | |
US3467759A (en) | Reiteration,percussion and speaking tone effects in electronic music generation | |
US2902655A (en) | Transistor oscillators | |
US4228713A (en) | Programmable current source for filter or oscillator | |
US3165707A (en) | Zener diode noise generator with feedback for threshold maintenance | |
US3837254A (en) | Organ pedal tone generator | |
US4057769A (en) | Circuit for generating two distinctive tone bursts with exponentially decaying envelopes | |
US3821459A (en) | Percussion to direct keying switching circuit for an electrical musical instrument | |
US3143712A (en) | Electronic musical instrument including cascaded transistor oscillators | |
US2962663A (en) | Frequency divider circuit | |
US3609204A (en) | Vibrato system for electrical musical instrument |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: GENERAL ELECTRIC CREDIT CORPORATION, A NY CORP., C Free format text: SECURITY INTEREST;ASSIGNOR:BPO ACQUISITION CORP., A DE CORP;REEL/FRAME:004297/0802 Effective date: 19840615 Owner name: SECURITY PACIFIC BUSINESS CREDIT INC., 10089 WILLO Free format text: SECURITY INTEREST;ASSIGNOR:BPO ACQUISITION CORP. A CORP OF DE;REEL/FRAME:004298/0001 Effective date: 19840615 |
|
AS | Assignment |
Owner name: BPO ACQUISITION CORP., 180 GILBERT AVE., CINCINNAT Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:D.H. BALDWIN COMPANY AN OH CORP.;REEL/FRAME:004385/0934 Effective date: 19840615 |
|
AS | Assignment |
Owner name: BALDWIN PIANO & ORGAN COMPANY Free format text: CHANGE OF NAME;ASSIGNOR:BPO ACQUISTION CORP.;REEL/FRAME:004473/0501 Effective date: 19840612 |