US3880039A - Sample and hold circuit for an electronic organ - Google Patents
Sample and hold circuit for an electronic organ Download PDFInfo
- Publication number
- US3880039A US3880039A US445985A US44598574A US3880039A US 3880039 A US3880039 A US 3880039A US 445985 A US445985 A US 445985A US 44598574 A US44598574 A US 44598574A US 3880039 A US3880039 A US 3880039A
- Authority
- US
- United States
- Prior art keywords
- voltage
- point
- resistance
- switches
- 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
- G10H1/18—Selecting circuits
- G10H1/22—Selecting circuits for suppressing tones; Preference networks
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S84/00—Music
- Y10S84/02—Preference networks
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S84/00—Music
- Y10S84/08—Keyed oscillators
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S84/00—Music
- Y10S84/10—Feedback
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S84/00—Music
- Y10S84/20—Monophonic
Definitions
- 8f4/1.24 X provides a virtual ground physically ungrounded at a 3.538.804 l l/l970 George 84/1 .0l point ofthe cascade of resistances corresponding with 3.569.603 3/1971 Kern 84/DIG. l0 that closed switch of several which represents the 3.609.201 9/1971 Antichi.. #i4/1.0i highest me Pklyed, 3.609.203 9/1971 Adachi 84/l.()l 3.659.031 4/1972 Adachi P14/L0! i9 Claims.
- the Bunger system includes a sample and hold circuit which is interposed between the source of control voltage which ultimately controls the tone signal source. and the voltage control terminaI directly applied to that source for effecting frequency control. That sample and hold circuit must be precise, i.e., its output voltage must equal its input voltage. However, various diode drops occur in the sample and hold circuit. which must be compensated for.
- the diode drops i.e., the voltage between base and emitter for a transistor. or the voltage across a diode, are temperature sensitive ⁇ and there occurs a failure of precise tracking as a function of temperature, which in turn rcsults in imprecision of tuning.
- the sample and hold system ofthe Munch, et al., application represents a solution to the problem of temperature dependence, and also eliminates inaccuracies of tuning which may result from variations of supply voltages, and of imprecision of amplifier gains, in that output voltage of the system, representing a desired tone frequency, is controlled by a negative feedgack loop extending around the entire sample and hold circuit, and in that the feedback loop is reference to one fixed voltage.
- the present invention additionally solves the problem of variation of switch contact resistance.
- a sample and hold circuit in a monophonic electric organ in which organ keys set a zero voltage point along an array of resistances, and in which a negative feedback circuit extends from the output of the sample and hold circuit to the array of resistances and serves to maintain a predetermined point ofthe array of resistances at constant voltage regardless of the resistance to ground to the array when any of the keys is operated.
- FIG. I is a circuit diagram of a system as disclosed in Munch, etal., Ser. No. 370,283, tiled lune l5, i973 assigned to the assignee of the present invention.
- FIG. 2 is a circuit diagram of the system ofthe present, invention, connected to the system of FIG. l.
- the system can be divided into three sections. The first is called the sample and hold section. and provides a voltage that corresponds to the highest note key being played, or. if no keys are presently being played, to the last highest not key that was played. This section is illustrated and described in Munch, supra.
- FIG. I contains integrated circuits ICI() and lCll which are operational amplifiers.
- the current sources Il through I4, which are constructed with transistors and resistors, are described in Munch Ser. No. 370,283.
- the current sources are under the control of the voltage Vl. When the voltage Vl is below 5 volts, current sources I3 and I4 are turned on. When the voltage VI is between 5 volts and 20 volts, all four current sources are essentially turned off (open circuit). When the voltage VI is above 2() volts, current sources II and I2 are turned on. In addition to providing an On Off control ⁇ the voltage VI determines the magnitude of these current sources.
- the ratio of I2 to Il when these current sources are turned on is equal to the ratio of I4 to I3 when the latter current sources are turned onA
- the operation of the sample and hold under various conditions is as follows. With any' switch SI-S37 closed ⁇ transistor 0105 is turned off which allows diode D51 to become forward biased through R549 and R550 if Vl does not fall below 0.8 volt. This condition on Vl is always satisfied. Transistor 0106 is off because its emitter is held at 5 volts and its base is a diode drop above that voltage. These two transistors are now essentially out of the circuit.
- the desired output voltage V3 with any key switch closed is the value that will cause the voltage V2 to be 5 volts.
- the voltage V2 is determined by the resistor voltage divider consising of resistance R571 and all switch resistors from RI to the resistor immediately preceding the switch that is closed, and the output voltage V3. For example, with switch S3 closed and II through I4 equal to zero, which occurs while VI is between 20 and 5 volts, the voltage V2 will be related to the output voltage by the following expression:
- the negative input of the operational amplifier must be at a higher voltage than the positive input. Since the required change in voltage from nominal at vl is l volts l5-5), the voltage difference required between the positive and negative inputs must be this voltage divided by the gain of the operational amplifier. This gain is infinity in theory and in practice is typically above l00,000. This results in a required voltage difference between the operational amplifier inputs of l0 ⁇ volts 100,000 vous "01ml ""l This voltage Av is called the differential input voltage and is added to the voltage at the positive input terminal to obtain the voltage V2, i.e., V2 5 volts 0.000l volts 5.00I volts. The small value of this differential input voltage implies that for'practical purposes. the differential voltage is zero and both terminals are at the same voltage. This assumption remains true whenever negative feedback like that provided by I3 is present.
- the initial value of the current souce I3 is now calculablc because the value of V2 has been determined to be +5 volts.
- the current through R571 is known because its value is specified and the voltage across it is known. Likewise the current through the switch resistors is known and I3 must be the difference between these two.
- Equations (2) and (4) show that I3 equals zero if V3 is at the desired voltage and that I3 is dependent upon the difference between the actual value of the output voltage and the desired value.
- Current source I4 is dependent upon I3. Its value therefore also depends upon this error voltage.
- Current source I4 discharges capacitor C523 whose voltage is amplified by transistor 0114 and lCll to become the output voltage V3. The output voltage V3. therefore, begins to fall and approaches the desired value. As the voltage V3 approaches the desired value, I3 and I4 are reduced which slows the discharge of C523. When the output voltage V3 reaches the desired value, both current sources are turned off and the discharge of C523 stops. The speed with which this process takes place is determined by the ratio of current source I4 to I3.
- Vl can be at any voltage between 5 and 20 volts.
- Capacitor C519 provides additional negative feedback from VI to V2 which slows the rate of voltage change at Vl. This is necessary to both protect against large noise spikes and to protect against noise from the key switches during opening and closing operations.
- the output voltage therefore remains at the value corresponding to the last key played.
- the hold time is determined by the ability of capacitor C523 to hold charge ⁇ which explains the need for the buffer amplifier consisting of 0114 and ICI l.
- This amplifier has a DC gain of 2 with respect to l5 volts which means that a voltage of I8 volts at the positive terminal of ICll will produce an output voltage of 2l volts. This gain reduces the voltage swing required at capacitor C523 to produce a given voltage range at the output.
- Resistors R568 and R569 provide the resistor divider necessary to supply an effective l5 volts with a 10K impedance to the junction of R570 and the negative input of ICI l, which is required to give the amplifier this gain.
- Resistor R567 provides bias current for transistor QI I4 and resistors R545, R547, R546 and R544 are current limiting resistors, which prevent destruction of their associated active components under accidental short circuit conditions.
- Capacitors C518 and C520 provide additional noise and switch bounce protection.
- the connector plugs 1, 2, 3 are connected. respectively, to corresponding plugs in FIG. 1 and to resistance R544, resistance R545, and lead D of FIG. 1 respectively.
- transistors 0127 0163 are substituted and connected to adjust the junctions to virtual ground, and these transistors have their bases connected to grounded base lead 50 via the switches S 1-S37.
- a switch, as S1 is closed, its associated transistor. as 0127, is rendered conductive, since its emitter is connected to a negative voltage point, i.e., the collector of 0164, which has its emitter connected to a negative lead 51.
- transistors 0127 to 0138 are interconnected via diodes as Dl to D11, only D11 being illustrated, which serve to isolate these emitters from each other and to provide certain voltage drops.
- 0127 employs no diodes, and in general the highest note transistor of each octave includes no diode while all other note transistors do, the circuit of 0150 being typical.
- the operational amplifier IC12 is supplied with 5 volts at its terminal 7, its terminal 2 is connected via a small resistance R809 and lead 54 to the last resistance R37 of the resistance chain R1 R37, and therefore has a 5 volt voltage applied thereon, if no key is operated ⁇ because the input resistance at terminal 2 of IC12 is almost infinite.
- the terminal 4 is connected to lead 55, which is held at volts.
- the lead 55 is connected to ground via resistances R807, R806, R804, R802, R801.
- resistances R806 and R804 are at l2/2 volts, the junction of resistances R804 and R802 at -l lz volts, and the junction of resistances R802 and R801 at l01& volts, and these voltages are steady voltages, applied to the bases of 0166, 0165 and 0164, respectively.
- the emitters of these transistors have variable voltages applied to them. For no keys closed. the voltage at point 57 is -20 volts.
- the bases of 0165 and 0164, but not of 0166, are connected to the points 60, 61 via diodes D57 and D56, respectively, which serve to mutually isolate the bases of the transistors 0165 and 0164 from the -111/2 and -lOl/ volts references.
- Point A of the resistor chain Rl to R37 is held at -5 volts, as by the circuitry of FIG. 1. lf no key switch is closed, this voltage is applied through R1-R37 to the 2 lead of IC 1 2, which is referenced to zero volts. The output of IC12 therefore approaches -20 volts, since this is the voltage applied to terminal 4 of IC12. These are the conditions if none of switches S1-S37 are closed.
- the base-emitter junction of the associated transistor will be forward biased, and will provide negative feedback for IC12.
- S24 the output voltage of IC12 will fall to about -12 volts, which in turn will turn on 0165.
- the voltage at the collector of 0165 will then fall to approximately 7.2 volts, equal to the voltages across eleven forward baised diodes. as D1 to D11, and one forward biased emitter junction.
- the forward biased diodes are those connected to the emitters of 0150 to 0140, no diode being present at 0139, and the emitter junction being that of 0150.
- Transistor 0150 then turns on because it has a current path through 0165.
- Each of the three octaves is connected to the output of IC12 through a separate transistor, i.e., 0166, 0165 and 0164. These three transistors provide highest octave preference due to the diverse voltages applied to their bases. The highest note played will always force its associated one of transistors 0164 ⁇ 0165 and 0166 to turn on. which will prevent a lower octave from turning on.
- any lower note is inoperative, because the associated lower octave transistor or transistors of0l64, 0165, 0166, if any exist. cannot become conductive, and because lower note transistors within an octave cannot become conductive.
- Resistances R38 to R44 are to provide precision of resistance values for the resistances R1 to R37.
- the latter are l.7f resistances and are connected in groups of six across resistances R38 to R44. It can then be the case, absent R38-R44, that a 6.7: error of resistance will exist.
- the resistances R38-R44 are selected to provide precisely the required resistance for the six resistor group.
- R38 merely parallels R1, and these can be considered a single precise resistance ⁇ i.e., R38 compensates for error in R1 only.
- An electric organ comprising an array of keys of said organ. a resistance having points corresponding respectively with said keys, means responsive to actuation of any selected key of said array of keys for providing a physically undgrounded point of zero voltage at a point of said resistance corresponding with the selected key, said resistance having an invariable point of reference potential, means including a feedback loop for maintaining the voltage of said invariable point of reference potential constant where any of said keys is actuated by feeding back current through said resistance in amplitude sufficient to maintain constant said 7 voltage of said invariable point of reference potential.
- said feedback loop including a storage capacity.
- a voltage controlled tone signal oscillator responsive to the voltage of a point of said feedback loop, and means for acoustically transducing said tone signal.
- a further high gain high input resistance feedback loop means responsive to closure of any selected one of said key switches for controlling the voltage drops along said array' of series connected resistances to provide said zero voltage at a junction of said array corresponding with the selected one of said key switches in response to the feedback action of said further feedback loop.
- said means responsive to any selected key of said array of keys includes a voltage divider having points each corresponding with one of said first mentioned points, normally open electronic switches closable in response to actuations of said keys and each connecting one of said points of said resistance with one of said points of said voltage divider, and a further feedback loop between said voltage divider and said resistance.
- An electric organ comprising an array of key switches.
- a resistance means responsive to operation of any combination of said key switches for adjusting the value of said resistance by providing one physically undergrounded point of zero voltage at any of plural preselected discrete points of said resistance corresponding with only one of said key switches ⁇
- circuit means including a voltage comparator extending from an invariable point of said resistance to an output point, a resistive feedback loop extending from said output point to said further invariable point.
- a source of reference voltage means for developing an input error signal for said voltage comparator as the difference of said reference voltage and the voltage of said invariable point, a voltage controlled tone signal source connected to said output point ⁇ and means for acoustically transducing the signal output of said tone signal source.
- said resistance includes plural arrays of series connected resistances, said arrays being connected in series. said arrays having junctions corresponding onefor-one with said key switches, further feedback loops, each including one of said arrays and all including a common high gain high input resistance operational amplifier, means responsive to closure of any selected plurality of said key switches concurrently for completing only that one of said feedback loops corresponding with that one of said arrays containing a junction corresponding with the highest pitched one of said key switches. and means further responsive to said closure of said selected plurality' of said key switches to provide 5 said undergrounded point of zero voltage at the last mentioned junction in response to the action of said further feedback loop.
- said means responsive to operation of said key switches includes a separate normally open solid state switch operatively associated with each of said key switches, means responsive to closure of. each of said key switches for rendering conductive the solid state switch associated with that key switch, a diode voltage divider chain interconnecting first corresponding terminals of said solid state switches to discrete points of said diode divider chain, said diode divider chain including identically poled diodes in series, a load circuit terminating said diode divider chain, a voltage comparator device including a source of reference potential and an input terminal for applying voltage for comparison with said reference potential by said voltage comparator device, and means responsive to the output of said comparison device for controlling the potential at said variable load circuit terminating said diode voltage divider chain ⁇ and means supplying voltage from one end of said resistance to said input terminal of said comparison device, said voltage comparison device providing a negative feedback loop extending from said one end of said resistance to said variable load circuit, said voltage comparison device being arranged to draw substantially zero current from said resistance via said
- said means responsive to actuation of any selected key of said array of keys includes a separate normally open solid state switch connected to be closed in response to operation of each of said keys, an amplifier, and a further feedback circuit extending through any closed ones of said solid state switches to the output of said amplifier and via said resistance to the input of said amplifier.
- an organ system a chain of equal series connected resistances extending from a first point to a second point, a chain of equal impedances providing equal voltage drops thereacross extending from a third point to a fourth point ⁇ an amplifier having an input and an output, means applying a voltage to said first point ⁇ means connecting said second point to said input ⁇ means connecting any selected junctions of said resistances to selected ones ofjunctions of said impedances, means connecting said fourth point to said output, said third point floating, wherein is provided means for maintaining said first point at a fixed voltage, a voltage controlled tone signal oscillator, means responsive to said last means for controlling the frequency of said voltage controlled oscillator. and means for transducing the tone signal output of said oscillator.
- An electric organ comprising an array of normally open key switches. an array of electronic switches, each of said key switches when closed rendering conductive one of said electronic switches, a series resistance chain having junctions corresponding one for one and each connected to one terminal of one of said electronic switches, a diode chain including series connected correspondingly poled diodes, means connecting the remaining terminals of said electronic switches one for one with corresponding electrodes of said diodes, a source of control voltage, means applying said control voltage to one end of said resistance chain.
- an amplifier having an input terminal and an output terminal, means connecting the other end of said resistance chain to said input terminal, means connecting one end of said diode chain to the output terminal of said amplifier, said resistance chain, diode chain and electronic switches being arranged and interconnected to provide a circuit from said source of control voltage through resistances of said resistance chain and via closed ones of said electronic switches and via said diode chain to said output terminal, and said resistance chain alone providing a circuit from said source of con trol voltage to said input terminal.
- An electric organ comprising a series connected array of resistances having a reference point, means including key switches for bringing any selected junction of said array of resistances to a physically ungrounded zero potential, said junction being a function of the operated key switches, a comparison circuit responsive to the voltage of said reference point and to a xed reference voltage for generating an error signal ⁇ a storage capacitor, current source and drain means responsive to said error signal for controlling the charge of said capacitor, an output terminal, means amplifying the voltage across said storage capacitor to provide an amplitied version of said voltage across said capacitor to said output terminal, a resistive feedback circuit extending from said output terminal to said reference point, a
- tone controlled tone signal oscillator connected to said output terminal and responsive to the voltage of said output terminal to generate tone frequency signals of variable frequency, and means for asoustically transducing said tone frequency signals.
- said means including key switches for bringing any selected junction of said array of resistances to a physically ungrounded zero potential includes a voltage divider chain. solid sate switches responsive to closure of said key switches for connecting said selected junctions one for one with points of said voltage divider. and a further feedback circuit connecting an end point of said voltage divider with and end point of said array of resistances.
Abstract
Description
Claims (19)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US445985A US3880039A (en) | 1974-02-26 | 1974-02-26 | Sample and hold circuit for an electronic organ |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US445985A US3880039A (en) | 1974-02-26 | 1974-02-26 | Sample and hold circuit for an electronic organ |
Publications (1)
Publication Number | Publication Date |
---|---|
US3880039A true US3880039A (en) | 1975-04-29 |
Family
ID=23770904
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US445985A Expired - Lifetime US3880039A (en) | 1974-02-26 | 1974-02-26 | Sample and hold circuit for an electronic organ |
Country Status (1)
Country | Link |
---|---|
US (1) | US3880039A (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3948137A (en) * | 1974-03-15 | 1976-04-06 | Nippon Gakki Seizo Kabushiki Kaisha | Pitch determining voltage signal generating circuit for a voltage controlled type electronic musical instrument |
US4064777A (en) * | 1975-09-08 | 1977-12-27 | Roland Corporation | Circuit for preferentially selecting highest and lowest tones |
US4098162A (en) * | 1975-12-15 | 1978-07-04 | Nippon Gakki Seizo Kabushiki Kaisha | Synthesizer type electronic musical instrument |
US4170160A (en) * | 1978-06-09 | 1979-10-09 | Jong Guo | Electronic musical instrument |
US4408514A (en) * | 1976-06-25 | 1983-10-11 | Nippon Gakki Seizo Kabushiki Kaisha | Electronic musical instrument having portaments property |
USRE32445E (en) * | 1976-06-25 | 1987-06-30 | Nippon Gakki Seizo Kabushiki Kaisha | Electronic musical instrument having portamento property |
Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2568797A (en) * | 1949-03-19 | 1951-09-25 | Philco Corp | Microphonic suppression system for electric phonographs |
US2933699A (en) * | 1956-11-15 | 1960-04-19 | Pacific Mercury Television Mfg | Frequency control means for monophonic tone generating oscillator |
US3288904A (en) * | 1962-09-25 | 1966-11-29 | Hammond Organ Co | Tone frequency control system for electronic musical instruments |
US3535430A (en) * | 1967-01-23 | 1970-10-20 | Motorola Inc | Transistor frequency glide control for musical twin-t oscillator tone generators |
US3538804A (en) * | 1968-06-06 | 1970-11-10 | Hammond Organ Co | Electronic solo instrument having high-note guard circuit |
US3569603A (en) * | 1968-08-01 | 1971-03-09 | Hammond Corp | Moving formant band-pass amplifier for an electronic musical instrument |
US3609203A (en) * | 1969-10-06 | 1971-09-28 | Nippon Musical Instruments Mfg | Partamento musical instrument having a single tone and envelope control |
US3609201A (en) * | 1969-08-22 | 1971-09-28 | Nippon Musical Instruments Mfg | Variable pitch narrow band noise generator |
US3659031A (en) * | 1969-10-10 | 1972-04-25 | Nippon Musical Instruments Mfg | Monophonic electronic musical instrument with a variable frequency oscillator employing positive feed back |
US3733955A (en) * | 1971-12-06 | 1973-05-22 | Venture Technology Inc | Music synthesizer keyboard circuit |
US3776087A (en) * | 1969-05-14 | 1973-12-04 | Nippon Musical Instruments Mfg | Electronic musical instrument with variable impedance playboard providing portamento |
US3786166A (en) * | 1972-05-19 | 1974-01-15 | Keio Giken Kogyo Kk | Keyboard type electronic musical instrument |
-
1974
- 1974-02-26 US US445985A patent/US3880039A/en not_active Expired - Lifetime
Patent Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2568797A (en) * | 1949-03-19 | 1951-09-25 | Philco Corp | Microphonic suppression system for electric phonographs |
US2933699A (en) * | 1956-11-15 | 1960-04-19 | Pacific Mercury Television Mfg | Frequency control means for monophonic tone generating oscillator |
US3288904A (en) * | 1962-09-25 | 1966-11-29 | Hammond Organ Co | Tone frequency control system for electronic musical instruments |
US3535430A (en) * | 1967-01-23 | 1970-10-20 | Motorola Inc | Transistor frequency glide control for musical twin-t oscillator tone generators |
US3538804A (en) * | 1968-06-06 | 1970-11-10 | Hammond Organ Co | Electronic solo instrument having high-note guard circuit |
US3569603A (en) * | 1968-08-01 | 1971-03-09 | Hammond Corp | Moving formant band-pass amplifier for an electronic musical instrument |
US3776087A (en) * | 1969-05-14 | 1973-12-04 | Nippon Musical Instruments Mfg | Electronic musical instrument with variable impedance playboard providing portamento |
US3609201A (en) * | 1969-08-22 | 1971-09-28 | Nippon Musical Instruments Mfg | Variable pitch narrow band noise generator |
US3609203A (en) * | 1969-10-06 | 1971-09-28 | Nippon Musical Instruments Mfg | Partamento musical instrument having a single tone and envelope control |
US3659031A (en) * | 1969-10-10 | 1972-04-25 | Nippon Musical Instruments Mfg | Monophonic electronic musical instrument with a variable frequency oscillator employing positive feed back |
US3733955A (en) * | 1971-12-06 | 1973-05-22 | Venture Technology Inc | Music synthesizer keyboard circuit |
US3786166A (en) * | 1972-05-19 | 1974-01-15 | Keio Giken Kogyo Kk | Keyboard type electronic musical instrument |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3948137A (en) * | 1974-03-15 | 1976-04-06 | Nippon Gakki Seizo Kabushiki Kaisha | Pitch determining voltage signal generating circuit for a voltage controlled type electronic musical instrument |
US4064777A (en) * | 1975-09-08 | 1977-12-27 | Roland Corporation | Circuit for preferentially selecting highest and lowest tones |
US4098162A (en) * | 1975-12-15 | 1978-07-04 | Nippon Gakki Seizo Kabushiki Kaisha | Synthesizer type electronic musical instrument |
US4408514A (en) * | 1976-06-25 | 1983-10-11 | Nippon Gakki Seizo Kabushiki Kaisha | Electronic musical instrument having portaments property |
USRE32445E (en) * | 1976-06-25 | 1987-06-30 | Nippon Gakki Seizo Kabushiki Kaisha | Electronic musical instrument having portamento property |
US4170160A (en) * | 1978-06-09 | 1979-10-09 | Jong Guo | Electronic musical instrument |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US3883756A (en) | Pulse generator with automatic timing adjustment for constant duty cycle | |
US3880039A (en) | Sample and hold circuit for an electronic organ | |
GB1570593A (en) | Method and apparatus for reproducing an electrical signal | |
GB1442063A (en) | Electronic musical instruments | |
US3789718A (en) | Voltage controlled chord organ | |
US3283057A (en) | Keyboard oscillator circuit | |
US3992969A (en) | Changeable preset system for electronic organs | |
US3248655A (en) | Ratchet memory circuit and sampling system employing such circuit | |
US3872764A (en) | Sample and hold circuit for an electric organ | |
US3930429A (en) | Digital music synthesizer | |
US3948137A (en) | Pitch determining voltage signal generating circuit for a voltage controlled type electronic musical instrument | |
US4160235A (en) | Pulse generator | |
KR950005155B1 (en) | Constant current circuit and oscillating circuit controlled by the same | |
US4028978A (en) | Synthesizer type electronic musical instrument with volume envelope decay time control | |
US4377790A (en) | Precision differential relaxation oscillator circuit | |
US4193040A (en) | High-voltage amplifier with low output impedance | |
US4085374A (en) | Generator for generating control voltage waveform | |
US3008088A (en) | Synchronized multivibrator with selectable clamping means for rendering it inoperative | |
EP0165748B1 (en) | Oscillator circuit | |
US4271743A (en) | Envelope signal generator | |
US4408514A (en) | Electronic musical instrument having portaments property | |
US3557296A (en) | Musical instrument driving circuit for producing percussion sound | |
US4090426A (en) | Contour generator for audio signal | |
US3162817A (en) | Current switching circuits | |
US3024368A (en) | Linear ramp waveform generating circuit with provision to cause stepping |
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 |
|
AS | Assignment |
Owner name: FIFTH THIRD BANK, THE, A OH BANKING CORP., OHIO Free format text: SECURITY INTEREST;ASSIGNOR:BALDWIN PIANO & ORGAN COMPANY, A CORP. OF DE.;REEL/FRAME:005356/0333 Effective date: 19890615 Owner name: BALDWIN PIANO & ORGAN COMPANY, F/K/A/ BPO ACQUISIT Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:SECURITY PACIFIC BUSINESS CREDIT, INC., A CORP. OF DE.;REEL/FRAME:005356/0321 Effective date: 19890616 |