DE2000155A1 - Synthesizer - Google Patents

Description

HAMMOND CORPORATION, Deerfield, 111./USA synthesizer

The present invention relates to a synthesizer for synthesizing and controlling complex musical output signals from a plurality of electrically simpler electrical input signals.

A form of electric organ generates all necessary tones of the tone scale with the help of square wave signals. Square wave signals namely have a certain proportion of harmonics, although the even harmonics are excluded are. As a result, various circuits have been proposed for eliminating unbalanced square waves Derive waveforms such as sawtooth waves. One can proceed in such a way that a plurality of precisely dimensioned square waves occur one after the other is arranged, resulting in a stepped wave function. The previous circuits of this type were, however, relatively complex in terms of their structure.

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adorns. Furthermore, there was the precision for the dimensioning of the individual square waves are not always satisfactory.

The aim of the present invention is to provide a synthesizer, particularly for electrical musical instruments to create which does not have these disadvantages and which is relatively simple to generate allows more precise step-shaped wave functions.

According to the invention this is achieved in that a semiconductor device with a common gate, a common output and a plurality of inputs intended for the individual reception of a plurality of input signals are provided, furthermore that the semiconductor device is normally not conductive, but on predetermined changes in potential responds to the gate, whereby the plurality of input circuits of the semiconductor device at the common Output results in a current flow, which is the mixing of a plurality of input signals into one mixed The output signal also causes the individual input circuits of the semiconductor device to be graded individual Have impedance elements for determining the size of the individual input signals and that Control devices are provided in order to produce a change in potential on the gate as desired.

With such a training the mechanism for

Striking the signals integrated with the actual synthesizing circuits. According to the invention is a synthesizer to synthesize electrls rather output signals from a plurality of electrical input signals.

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seen. This synthesizer includes a semiconductor device that has a common gate and a common Output, however, has a plurality of inputs. The gates control the between the inputs and the common output current flowing. The inputs individually carry one of the plurality of input signals. As soon as a gate with a given stop signal is connected, a current flows from the plurality of inputs via the semiconductor arrangement, whereby the result is an output signal that synthesizes the various inputs.

A plurality of such synthesizers are constituted by a plurality of synthesizing units connected by signal inputs and at least one stop input. The unit holds an exit for everyone Synthesizer and is used to synthesize at least two different output signals as a function of the Pressing a key.

Such a synthesizing unit is expediently built into an electronic musical instrument, which Elements for generating a plurality of square-wave signals with different frequencies, keystrokes with such Touch keys connected selection circles and conventional music signal changing elements, MiSCh and Includes amplifier circuits and one or more loudspeakers. The synthesizing unit is with a source for Square waves and the synthesizers connected, so that depending on the stroke of a key one of different Components existing staircase wave signal is formed at one or more outputs. The outputs of the synthesizing unit are connected to the conventional electrical musical instrument circuits « so that one or more musical tones are produced. the

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Key circles expediently have selector devices, whereby the rise and fall of the synthesized Output signals can be influenced, so that a tonal influencing of the generated musical tones is possible is.

Further details of the invention are to be explained in more detail below with the aid of exemplary embodiments will be described, reference being made to the accompanying drawing fc. Show it:

Fig. 1 is a schematic circuit diagram of an electronic organ with a synthesizing unit according to the invention.

Fig. 2 is a schematic circuit diagram of a first Embodiment of the synthesizer of FIG. 1.

3 shows a schematic circuit diagram of a modified one Embodiment of the synthesizer of Figure 1.

Fig. 4 is a schematic circuit diagram of a further from P converted embodiment of the synthesis

according to the invention.

In the following, reference should be made to FIG. 1, in which part of an electronic organ according to FIG of the invention is shown. The electronic organ 10 includes a generator 11 for generating a number of substantially equal amplitude square wave signals of different frequencies. According to of the present invention is a staircase waveform synthesizing unit 12 with the outputs of the generator

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connected to synthesize a particular output signal. The staircase waveform signals are dependent on the closing of switches - for example the Switches 82 and 8j5 of the organ keyboard - generated, where the button selection circuits 17 and 19 are operated. The exits of the synthesizing unit 12 are connected to conventional circuit change and gain circuits 18 of the organ connected, so that on one or more speakers, - for example the speaker 20 - a sound is generated will.

The synthesizing unit 12 has the dual functions of synthesizing and keying and thus forms a combined synthesizer and key box. this means that a certain output signal only then is synthesized when a certain associated key is pressed, so that unnecessary elements are omitted and unnecessary signals are not generated.

The synthesizing unit 12 has six input terminals 20A-P. To each of these input terminals 2OA-P If a different square-wave signal is supplied by the generator 11, as is the case, for example, with. 21 shown is. These signals differ in terms of their frequency. The frequency of the waveform of the input terminal 2OA corresponds to the fundamental tone, while the waveform occurring at * at terminal 2OB corresponds to the second harmonic, the fourth harmonic waveform appearing at terminal 2OC that occurs at terminal 2OD Eighth harmonic waveform, the sixteenth harmonic waveform appearing at terminal 20E and the waveform of the thirty-second occurring at terminal 2OP Harmonics. The following frequencies therefore occur at terminals 2OA - P: 220 Hz, 440 Hz, 880 Hz, 1760 Hz, 3520 Hz and -7940 Hz. Periods

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of the signals coincide with each other: As soon as the fundamental frequency is triggered, every harmonic occurs Wave up too.

The signals generated by terminals 20A-P are connected to individual synthesizers 30 A-E. These Synthesizers 30 A-E are identical to one another in terms of their construction and mode of operation, as shown in FIG Pig's discussion. 2 should be described in more detail. At the present point, however, it is sufficient fc to indicate that each of the synthesizers 3OA-E have five Has inputs 31 - 35 and an output 36.

The input signal at terminal 20A is fed via line 29 to input 34 of synthesizer 30A. A branch 55 from the line 59 also leads to the input 34 of the synthesizer 3OD. The input terminal 2OG is connected via a line 52 to the input 53 of the synthesizer 30A. Terminal 20B is also connected to inputs 34, 33 and 34 of synthesizers 30B, 30D and 30E via lines 55, 56 and 54, respectively. The input terminal 2OC is connected to the input 32 of the synthesizer 3OA via the line 53, the input terminal 2OC is also connected to the inputs 33, 34, 32 and 33 of the corresponding synthesizers 3OB, 3OC, via the lines 51 »49 and 52 and 50. 30D and 3OE connected. The input terminal 2OD of the synthesizing unit is connected via lines 48, 46, 44, 47 and 45 to the corresponding inputs 31 * 32, 33 * 31 and 32 of the synthesizers 30A, 30B, 3OC, 3OD and 3OE. The input terminal 20E of the synthesizing unit 12 is also connected to the inputs 31, 32 and 31 of the synthesizer 30B, 30c and 30E via corresponding lines 43, 41 and 42. Terminal 2OP is finally

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via a line 40 to input 31 - of the synthesizer 3OC connected.

As described above, the synthesizers 30A and D are connected to the input terminals 20A, 20B, 20C and 20D. The synthesizer 30B 3 ° C and 30 ^E, however, are connected to denEingangsklemmen 2OB, 2OC, 2oD and 2NC while the synthesizer 30C to the input terminals 2OC is 2oD connected 2NC and 2OP.

The inputs 35 of the synthesizers 30A, 30B and 30C are connected to a first input terminal 65 of the synthesizing unit 12 via lines 62, 61 and 60. In the same way, the inputs 35 of the synthesizer 30B and 30E are connected via lines 68 and 67 to a common key input terminal 70 of the synthesizing unit 12. The outputs 36 of the five synthesizers 30A-E are connected to the five output terminals 80, 78, 76, 79 and 77 via lines 75, 73, 71, I ^ and 72.

The key input terminals 65 and 70 are each with connected to one of the touch response circuits I7 or I9. There These circles are identical in terms of their construction, only circle I7 will be described below. The key response circuits I7 and I9 respond to key switches 82 and 83, each with the positive Potential terminal 84 are connected. Although the key switch 82 and 83 are shown as conventional key switches, it should be understood that others Switching devices - for example transistors or similar elements - can be used.

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The circuit 17 has an output line 85 with the terminal 65 of the synthesizing unit 12 is connected. Furthermore, a capacitor 86 is provided between this line 85 and a reference potential or earth is arranged. To control the rise time is a Resistor 87 is provided, which is arranged between the line 85 and the input of the switch 82. At the line 85 is also connected to a resistor 88, which is on the other side with the movable contact a switch 90 is connected. This switch 90 is mechanically connected to a second switch 9I. The movable contact of this second switch 91 is connected to a resistor 93 of the input line of the circuit 17 via a diode 92. The diode 92 is like this arranged that current only pass through the switch 9I can when the same is in position 91c, in which a circuit from the battery 95 across the Resistor 95 and switch 82 to battery 84 comes about. The fixed contacts of changeover switches 90 and 91 are labeled 90A - C and 9IA - C. The changeover switches 90 and 91 are mechanically coupled to one another in such a way that that at the same time via the contacts 90A and 9IA or 90B and 9IB or 9OC and 9IC a connection is established will. The contact 9OA is grounded, while the contacts 9IA and B are electrically isolated. Contacts 90B and 9IB are connected to each other and via a line to the positive voltage source 95 connected.

When the moving contacts of switches 90 and 91 with the contacts 9OA and 9IA are connected, the resistance is 88 in parallel with the capacitor 86, but the circuit existing as resistor 93 and diode 92 is isolated and

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therefore not effective. However, when the moving contacts are connected to contacts 9oB and 9IB, is the circuit consisting of resistor 93 and diode 92 isolated, however, the resistor 88 to the positive voltage source 95 connected. However, when the moving contacts are connected to the stationary contacts 9OC and 9IC are connected, the resistor 88 is connected to the voltage source 95 and also that of diode 92 and Resistor 93 existing circuit connected to it.

Reference should now be made to FIG. 2, in which one embodiment of the synthesizer 30 is shown. This synthesizer 30 has four metal oxide silicon field effect transistors (MOS-FET) - 104 on. These field effect transistors 101-104 are of the "p" channel type and are operated in the amplification mode. Such field effect transistors are also available as isolated gate field effect transistors JO-FET or metal oxide semiconductor MOS known. Such field effect transistors can be manufactured as discrete units with four connection elements: a gate G, a drain D, a source S and a substrate sub. The four field effect transistors 101-104 of the synthesizers 30 are electrically connected to their gates and via a line I05 to of the stop unit 38. The substrates of the field effect transistors 101-104 are also connected to one another via lines 106. Finally the drains of these transistors 101-104 are also interconnected via lines. The sources of the field effect transistors 101-104 are connected via lines 111, 112, 113, 114 / corresponding inputs 34, 33, 32 and 31. In accordance with the present invention, the effective source drainage resistances are the field effect transistors

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101 - 104 matched to each other, i.e. the source drainage resistances of the field effect transistors 101-104 behave in the conductive state as approximately 1: 2 : 4: 8. In general, a certain readjustment must be made in order to use the Load and source resistances etc. to be taken into account. For example, if the source drainage resistance of the field effect transistor 101 is 20 kOhm, the corresponding source drain resistance of the transistor is

102 40 kOhm, that of transistor 103 about 80 kOhm and that of transistor 104 about 160 kOhm. The purpose of this design is to approximate the Fourier series of harmonics for the sawtooth wave. The fundamental wave is 100 %, the second harmonic 50%, the third harmonic 33 1/3 %, the fourth harmonic 25 %, the fifth harmonic 20 % etc. In the four inputs described above, the missing harmonics are the seventeenth and multiples thereof . In the general case, the first missing harmonic carries 2 _r if η is the number of inputs.

All field effect transistors 101-104 have common substrates, as is shown in FIG. 2 by the abbreviation "sub is indicated next to the reference numeral 115.

As a result, it is possible to manufacture many of these switching elements in a closed unit, since many are there are common bonds. For example, in the case of the stop input 35, all lines 105 and the Gates of the field effect transistors 101-104 are integrated. Thus, the dashed lines in Pig.l Unit 12 shown can be produced as an integrated circuit on a common substrate.

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The substrate is held at a positive potential above ground with the aid of a positive voltage source 120, 1, a suitable connection 121 is provided. It is common practice to use a decoder diode protection provided by the diode 125, 126 is symbolized which between the stop input terminals 65 * 70 and the substrate are arranged. These Zener diodes or equivalents are preferably built into the unit, but during normal operation not effective.

The circuit described above is used to synthesize the square wave signals appearing at the inputs forming a staircase waveform as shown at 130. This waveform 1J50 occurs at the Output terminals 76 to 80 open as soon as a key - for example the key 82 or 85 - is depressed. Furthermore, the type of response to a single depression of the key 81 or 82 can be changed. For example, a long response characteristic or a slow decrease, a medium response characteristic or a rapid fall produces four den.

In the form of an example it should be mentioned that the frequencies of the square waves of the synthesizing unit 12 at terminals 20F-A are 7040, 3520, 1760, 88O, 440 and 220 Hz can. The input signals have peak values on the order of 4 volts, with the switching elements can be selected as follows: capacitor 86; 0.1 / uF, resistor 88; 10 MJ2, resistor 87J 22 kOhm, resistor 93; 53 kOhm. The voltage source 84 should be approximately -7 volts and the voltage source 120 is approximately +6 volts.

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Reference should now be made to FIG. 3, in which a modified embodiment of the synthesizer 30 ^f of FIG. 1 is shown. In this embodiment it is possible to use discrete switching elements. In general, however, it is preferable to use an integrated circuit. The synthesizer 30 * has four emitter NPN-type transistors 150, the common base of which is connected to the stop input 35 via a line 131 and whose common collector is connected to the output terminal 36 via the line 132. The four emitters of the transistors 130 are connected to corresponding inputs 31, 32, 33 and 34 via resistors 133, 134, 135, 136. The resistors 133, 134, 135, 136 are graded with respect to their resistance values 8: 4: 2: 1. This means that resistor 135 has twice the amount of resistor 136, resistor 134 has four times the amount of resistor 136 and resistor 133 has eight times the amount of resistor I36. For example, these resistors can be selected as follows: resistor 136 2 kOhm, resistor 135 4 kOhm, resistor 134 8 kOhm, resistor I33 16 kOhm. With this construction of the synthesizing unit 12, the values of the circuit 17 and the potential source 83 are different from the combined circuit of Fig. 1, although the basic arrangement is substantially the same. In the case of the unit 12 ', the switching elements can be selected as follows: capacitor 86 3 / uF, resistor 88 220 kOhm, resistor 87, 2.2 kOhm, resistor 93, 3.3 kOhm. The voltage source 84 should be +3 volts. The size of the capacitor 86 must also be increased relative to the synthesizing unit 12, depending on the number of the synthesizer 30 ' which are operated by the circuit 17 or I9 .

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The synthesizer 30 'is used to synthesize Stairform waveforms - for example, waveform 157 - at output J56 using the corresponding Inputs 31 - 34 occurring square waves 138 - l4l as a function of a stop signal at the stop input 35 · A rise in the base potential makes the transistor 130 conductive that those at the emitters existing signals are passed and combined at the common collector.

In the following we shall refer to Fig. ' 4 should be referred to, in which a modified embodiment of the synthetic (

tisierers 12 of Fig. 1 is shown. This synthesizer 12 'differs essentially in the provision of buffer semiconductor elements 122A-F, which are arranged between the corresponding input terminals 20A-F and the synthesizers 30A-E. The semiconductor elements 120A-F are positive channel MOSFET field effect transistors, the gates of which are connected via lines 140A-F to the corresponding input terminals 22A-F and their interconnected sources are connected to the substrate via a line 14l. The drains 200A-F of these transistors 120 AF are connected to the synthesizers 30 according to FIG. 4 in the same way as i the terminals 20A-F in the synthesizing unit 12 of FIG. 1 Zener diode protection or a corresponding equivalent should also be used according to FIG will. However, since this does not affect the normal functioning of the unit, and since the manner in which this can be done is known, this Zener diode protection is not particularly shown in FIG.

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The mode of operation of the synthesizing unit 12} of FIG. 4, which preferably have synthesizers 30 according to FIG is the same as for the unit 12 of FIG. 1 except that by the provision of the buffer field effect transistors 120A-F the mode of operation is improved.

It is evident that a new, improved synthesizing unit created with improved synthesizers which has been used for various purposes suitable is. The synthesizers 30 are very cheap to manufacture, consist of very few individual elements and require very little space, whereby the synthesizing and stop functions are combined. While the five synthesizers of the synthesizing unit 12 are preferably consist of integrated circuit elements and are manufactured at the same time, it is still possible to get many of the advantages of the invention, by yourself when discrete switching elements are used. Since many such units are usually in an electronic Organ or a similar electrical musical instrument is used, it is appropriate to have multiple units simultaneously on a single substrate. Indeed, it is believed that an integrated summary of several units on a common element - for example a substrate - the practice of the present invention appears most suitable.

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Claims (1)

- 15 patent claim e Synthesizers for synthesizing and controlling complex musical output signals from a plurality of electrical. simpler electrical input signals, characterized in that a semiconductor arrangement with a common gate, a common Output and a plurality of inputs intended for the individual reception of a plurality of input signals it is further provided that the semiconductor device is normally non-conductive, but at predetermined potential. ' tial Changes to the gate responds, which means about the plurality of input circuits of the semiconductor device at the common output results in a current flow, which the Mixing a plurality of input signals into a mixed output signal also causes the individual Input circuits of the semiconductor arrangement graded individual impedance elements for determining the size of the individual input signals, and that control means are provided as desired cause a potential change at the gate. 2. Synthesizer according to claim 1, characterized marked Λ ζ calibration η e ₄ t that the individual input signals oktavmäßig are RELATED square waves with each other, and that the impedances are selected such that upon occurrence of a change in potential at the gate of the the Signals occurring at the outputs are staircase signals. -16- 009830/1226 J>. Synthesizer according to claim 2, characterized geke η η - ζ calibration ne t, that the separate square wave input signals have fundamental wave corresponding to the fundamental wave, the second harmonic, the fourth harmonic, and the eighth harmonic, and that the impedances are selected such that the outcome of a mixed im Signals / essentially a fundamental wave with the value X, a second harmonic with the value X / 2, a 'third Harmonics with the value X / 3 and a fourth harmonic with the value X / 4. 4. synthesizer according to claim J>, characterized in that the semiconductor arrangement is a MOS-FET field effect transistor with at least four inputs, and that the effective resistances at the inputs are essentially 1: 2: 4: 8. 5. synthesizer according to claim 3, characterized in that the semiconductor device is a transistor Emitters, with a common base, a common collet ^ cor and at least four emitter inputs, and that the resistances present in the emitter inputs are essentially graded as 1: 2: 4: 8. 6. Synthesizer according to one of the preceding claims, characterized in that i chne t a) a common substrate is provided, through which separate semiconductor elements each with a common Gate, a common output and a plurality of separate inputs is formed, b) that the input-side circles of a first pair of such semiconductor elements are arranged in a first set, this set being connected to individual sources of harmonically related square waves, 009830/1226 _r . c) that the input elements of a second pair of semiconductor elements are interconnected to form a second set are, with the second movement with an octave lower individual sources of harmonic interconnected rectangular waves are connected as the sources of the first set, d) that the input elements of the fifth semiconductor element with in turn an octave lower individual Sources of harmoniously related square waves as the sources of the second sentence are related, e) further that a first common stop device for one of the gates of the first set, one of the Gate of the second set and the gate of the fifth semiconductor element and a second common stop device for the remaining gates of the semiconductor elements of the first and second set are available, f) and that there are switches to close these circuits. 009830/122 6