US3538806A - Tone processing system - Google Patents
Tone processing system Download PDFInfo
- Publication number
- US3538806A US3538806A US712117A US3538806DA US3538806A US 3538806 A US3538806 A US 3538806A US 712117 A US712117 A US 712117A US 3538806D A US3538806D A US 3538806DA US 3538806 A US3538806 A US 3538806A
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- US
- United States
- Prior art keywords
- output
- diode
- tone
- signal
- wave
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- 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
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- 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
- G10H1/06—Circuits for establishing the harmonic content of tones, or other arrangements for changing the tone colour
Definitions
- the conversion system is thus capable of 3,213,130 10/1965 C y el /1-1 1 responding to alternate half cycles of complex waves, over 21 3,256,381 6/1966 Cookerly et a]., 84/].27 very wide range of frequencies, say from about 50c.p.s. t0 ""Llfifi ll/l967 Diidek et al. 307/235X about 5,000c.p.s
- the prior art systems lack a suitable device for assuring that the fundamental of a complex musical tone will, for all frequencies and wave shapes, assume reliable control of the system, keeping in mind that wave shapes of tones produced by musical instruments, such asthe clarinet, differ radically among themselves in respect to wave shapes.
- wave shapes of tones produced by musical instruments such asthe clarinet
- many musical tones have harmonics which far exceed the fundamental in amplitude. In these circumstances the output of the system tends to shift at random in the course of playing a single note. It is to this problem that the present system primarily addresses itself.
- the output of an acousto-electrical transducer, controlled by a musical instrument, is applied to a push-pull diode peak detector which generates square waves at the frequency of the fundamental of the output of the transducer, for a wide variety of wave shapes and for a wide range of frequencies.
- the square wave is divided by two and again by two, and also is multiplied by two-thirds, thirds, followed by division by three, and multiplied by two.
- FIG. 1 is a block diagram of a system according to the invention.
- FIG. 2 is a schematic circuit diagram of a system according to FIG. 1.
- an audio input signal which may be derived from an acousto-electric transducer operatively associated with a horn, clarinet, guitar, or the like, is applied to a diode wave shaper 11, which converts the wave to one resembling a square wave having the same fundamental frequency as does the audio input signal.
- the output of the diode wave shaper drives a transistor flip-flop 12, which provides a square wave at the fundamental frequency, but of level amplitude regardless of the amplitude of the audio signal.
- the output of flip-flop 12 drives two cascaded divide-by-two circuits, 13 and 14, a multiply by two circuit and a multiply by circuit, each of which supplies complex signal to an array TC of tone color filters, selectable by operation of tabs, not illustrated.
- the output of array TC proceeds to a diode gate 16 which controls signal level in response to a DC control voltage applied via control lead 17, and which leads to an audio amplifier 18.
- the latter drives a loudspeaker 19. It follows that any complex audio tone, regardless of its wave shape, and of fundamental frequency F, can produce square waves of fundamental frequency F, F/2, 2F, F and another of fundamental frequency F/4.
- tone color filters TC can have the tone colors of various instruments, for example, clarinet, oboe, flute, tuba, saxaphone, dulciana.
- transducer 10 The output of transducer 10 is detected in smoothing detector 20, which provides DC gain control signal on lead 17, so that the level of sound emitted by loudspeaker 19 will follow that of transducer 10, and therefore of the level provided by the instrument with which the transducer is associated.
- a diode frequency doubler 21 To the outputs of flip-flop 12 is connected a diode frequency doubler 21. The latter derives a divide-by-three circuit 22, the output of which in turn is applied to the array TC of tone color filters.
- the frequency F as provided by flip-flop 12, the outputs of divide-by-two circuits 13, 14, the output of multiplier 21, and the output of divide-by-three circuit are applied via separate leads to tone color filters TC.
- the output of transducer 10 is applied via coupling capacitor 30 and base current limiting resistance 31 to the base of NPN transistor T having a grounded emitter.
- the collector of T is loaded by resistance 32, and the resistances 33, 34 serve to bias the base.
- Capacitor 35 provides frequency selective feedback to accentuate response as an inverse function of frequency, i.e. it provides roll off, which accentuates the fundamental of a complex wave at the expense of higher partials.
- the amplified audio signal-appearing at point 36 is superposed on a DC voltage of about l2.V representing DC supply voltage of 22.V less the DC voltage drop in resistance 32.
- a DC voltage of about l2.V representing DC supply voltage of 22.V less the DC voltage drop in resistance 32.
- To the point 36 are directly connected the base of diode D and the anode of diode D
- the double diode, double capacitor detection system may well be denominated a push-pull peak detector, since it responds to alternate polarities of a wave to provide a clipped AC output which approximates a square wave.
- the closeness of the approximation depends, however, on the complexity of the input wave form, Le. the relative amplitudes and phases of its component partials.
- D,, 44 is a peak detector
- D 43 is a peak detector, for negative and positive signals, respectively, capacitors 43, 44 being in series with respect to diodes D D and the circuit tends to produce a square wave at the peaks of the input wave form, changing state as the input signal reverses polarity.
- Current through load resistance 53 is then an AC signal with respect to the DC bias for transistor T established by resistances 51, 52, 53. Since the load and bias circuits for T and T are identical, the DC level at point 54 is nearly the same as the DC level at point 36. T saturates on sufficiently large signals, its output having values extending to 0 and 22.V as the comprising two cross-connected NPN transistors T and T in a configuration which is conventional and hence is not further described.
- the collector of T its emitter being grounded, is AC coupled via capacitor 60 to the cathode of a grounding diode D and to the anode of a series diode D the cathode of which is grounded through resistance 63.
- the capacitor 60 and resistance 63 convert the DC variations of voltage at the collector T to short pulses, of which only the positive halves pass to junction 61.
- a similar arrangement pertaining to the collector of T involves capacitor 62 and diodes D and D Diodes D and D together then pass each oscillation of FF-l, and the pulse frequency at junction 61 is double that supplied by T Essentially 60, 63 is a differentiator which is rendered inoperative to negatively going pulses by D D and 62, 63 is a further differentiator.
- the pulses available at junction 61 are applied to a divideby-three circuit 22, in the form of a ring counter of conventional configuration, via a drive amplifier 66 having an NPN transistor T Divide-by-three circuit 22 employs three cascaded NPN transistors T T T
- the output of amplifier 66 is applied jointly to the collectors of the transistors T T T through 2.2 K resistors 70, 71, 72, these being connected back to DC supply via resistance 73 (820 9).
- Each collector is connected back to the base of the preceding transistor, i.e. T to T T to T and T to T and forward via wave shaping circuits 74, 75, 76, respectively, i.e. T to T,, T-, to T and T to T,.
- the configuration is well known, and since circuit values are provided a detailed description of operational mode is dispensed with.
- the output of divide-by-three circuit 65 appears directly at the collector of T and is applied via a voltage divider 80 and lead 81 to an array of tone color filters TC, selective by tab operated switches (not shown) in a manner widely employed in electronic organs.
- the output of the array of tone color filters TC appears across resistance 82.
- FF-l The output of FF-l is applied to cascaded flip-flops 13 (FF- 2) and 14 (FF-3), arranged to operate as frequency dividers. These, and flip-flop 12, individually apply their outputs via leads 100, 83 and 84 to the array of tone color filters TC. lnterposed between the leads 100, 83 and 84 and the filters TC are adjustable voltage dividers 101, 85 and 86, respectively, which serve as volume adjusters. A further adjustable voltage divider 103, fed by lead 102 connected to the collector of transistor 66 is also provided and leads to tone color filters TC. At the input of the color filters TC can appear one or more of five signals, each of which bears a frequency relation to the frequency of the output of transducer 10.
- the outputs at leads 100, 81, 83, 84, 102 are square waves of frequencies F, 2 F/3, F/2, F/4, 2F, respectively, and any one or more of these may be selected by tab switches (not shown).
- the tones provided are, however, of preset amplitudes, which are not related to the level at which the instrument which energizes transducer is being played, in absence of the following provision.
- the direct output of transducer 10 is amplified in amplifier 20, comprising transistor T and rectified by diodes D D of detector 20, of which D shunts negative half cycles to ground and D passes positive half cycles.
- a long time constant load circuit 91 for D is connected between the cathode of D and ground, so that at junction 92 appears a DC voltage having a value nearly proportional to the peak value of the output of transducer 10.
- Junction 92 is the control point of a diode gate 16 composed of back-to-back diodes D D through which passes in series the signal across resistance 82.
- Diode gate 16 is nonconductive in absence of control voltage applied to control point 92, but becomes more conductive as control voltage increases.
- the signal passed by gate 16 passes to a voltage amplifier 18, including an NPN transistor T and the latter drives in cascade a power amplifier 18a and loudspeaker 19.
- said output is a complex wave
- transducer for coupling to said instrument and converting said acoustic tonal output to an electrical signal having a complex wave form
- said push-pull peak rectifier including a junction to which is applied said electrical signal
- a first capacitor connected to the anode of saiddiode; a load resistance connected in cascade with said first capacitor;
- diode differentiators responsive to all state transitions of said flip-flop to provide pulses at twice the frequency of operation of said flip-flop a divide-by-three counter circuit responsive to said pulses;
- a loudspeaker coupled to the output of said tone color filter array.
- An audio gain control'circuit including:
- a diode amplitude detector responsive to said tone signals for providing a DC signal constantly proportional in amplitude to said mean amplitude
- diode gate including back-to-back connected diodes with the connection of said diodes forming a control point
- said gate being arranged to be normally nonconductive in absence of said DC signals at said control point.
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- 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 |
---|---|---|---|
US71211768A | 1968-03-11 | 1968-03-11 |
Publications (1)
Publication Number | Publication Date |
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US3538806A true US3538806A (en) | 1970-11-10 |
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ID=24860825
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US712117A Expired - Lifetime US3538806A (en) | 1968-03-11 | 1968-03-11 | Tone processing system |
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Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3626076A (en) * | 1969-05-21 | 1971-12-07 | Nippon Musical Instruments Mfg | Mixer circuit for electronic musical instrument providing staircase tone signal |
US3748367A (en) * | 1971-10-21 | 1973-07-24 | S Lamme | Percussive musical instrument with transducer for actuating an electronic tone generator |
US3790693A (en) * | 1971-12-29 | 1974-02-05 | Nippon Musical Instruments Mfg | Tone keying and synthesizing system for electronic musical instrument |
US3825668A (en) * | 1972-05-30 | 1974-07-23 | Nippon Musical Instruments Mfg | Electronic musical instrument capable of providing a third type of musical tones by operation of two keyboards in addition to the ordinary melody and chord tones |
JPS5221822U (en) * | 1975-08-05 | 1977-02-16 | ||
US4195544A (en) * | 1977-03-25 | 1980-04-01 | Nippon Gakki Seizo Kabushiki Kaisha | Electronic musical instrument with external sound control function |
US4265157A (en) * | 1975-04-08 | 1981-05-05 | Colonia Management-Und Beratungsgesellschaft Mbh & Co., K.G. | Synthetic production of sounds |
US4313360A (en) * | 1980-03-26 | 1982-02-02 | Faulkner Alfred H | Harmonic generator for additive synthesis of musical tones |
-
1968
- 1968-03-11 US US712117A patent/US3538806A/en not_active Expired - Lifetime
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3626076A (en) * | 1969-05-21 | 1971-12-07 | Nippon Musical Instruments Mfg | Mixer circuit for electronic musical instrument providing staircase tone signal |
US3748367A (en) * | 1971-10-21 | 1973-07-24 | S Lamme | Percussive musical instrument with transducer for actuating an electronic tone generator |
US3790693A (en) * | 1971-12-29 | 1974-02-05 | Nippon Musical Instruments Mfg | Tone keying and synthesizing system for electronic musical instrument |
US3825668A (en) * | 1972-05-30 | 1974-07-23 | Nippon Musical Instruments Mfg | Electronic musical instrument capable of providing a third type of musical tones by operation of two keyboards in addition to the ordinary melody and chord tones |
US4265157A (en) * | 1975-04-08 | 1981-05-05 | Colonia Management-Und Beratungsgesellschaft Mbh & Co., K.G. | Synthetic production of sounds |
JPS5221822U (en) * | 1975-08-05 | 1977-02-16 | ||
JPS5728236Y2 (en) * | 1975-08-05 | 1982-06-19 | ||
US4195544A (en) * | 1977-03-25 | 1980-04-01 | Nippon Gakki Seizo Kabushiki Kaisha | Electronic musical instrument with external sound control function |
US4313360A (en) * | 1980-03-26 | 1982-02-02 | Faulkner Alfred H | Harmonic generator for additive synthesis of musical tones |
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Legal Events
Date | Code | Title | Description |
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AS | Assignment |
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 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 |
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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 |
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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 |