The Wurlitzer Company

Robert W Wheelwright

Peter E Solender

An automatic chord control system is readily incorporated in an electronic organ by means of large scale integrated circuit chips. The automatic chord control causes a chord or group of notes within an octave played on the lower manual keyboard to play through the upper manual voice in the octave below the lowest melody note being played on the upper manual keyboard. The proposed automatic chord control system has two operating modes. In the first mode, the notes transferred to the upper manual are generated in direct correspondence to the keys activated on the lower manual. In the second mode, the notes transferred to the upper manual are generated by a set of preset chords activated by single lower manual keys.

Automatic chord control circuit for electronic musical instruments

A LSI (large scale integrated circuit) device is disclosed which generates 12 output frequencies related to each other by a multiple of the twelfth root of two from a common time base without the use of parallel divider or shift register strings. The output frequencies comprise the top octave, or a multiple thereof, of the frequencies of an electronic musical instrument. A binary counter serves as a common time base and encodes each wave form period in a form of a binary code. A binary processing circuit associated with each output frequency stores the count position of the next desired wave form transition and updates the stored code after each transition has occurred. The binary processing circuitry comprises a latch circuit, a binary full adder or ROM (read only memory), a digital comparator or ROM, and a J-K flip-flop circuit. The outputs can be easily modified in both actual frequency and waveform symmetry.

Digitally encoded top octave frequency generator

A non-volatile programmable memory storage system for use with electronic musical instruments is provided which utilizes an erasable and reprogrammable read only memory (EPROM). The EPROM is provided with suitable erasure means, either electrical or ultraviolet light. Also provided is means for entering and retrieving data from the EPROM and means for bidirectionally transferring data between the EPROM and the electronic musical instrument.

Programmable memory system for electronic musical instrument

A tone-generating system for an electronic musical instrument of the percussion type is provided wherein an audible tone closely approximating the corresponding tone of a conventional instrument is generated electronically. A single-pole, double-throw switch is actuated by a key to initiate generation of the tone and a tri-level detecting circuit coupled to the switch is utilized to determine which of the three states the switch is in; that is, the two 'throws' or positions of the switch which correspond to the released and depressed positions of the key, and the state in which the switch is between the other two positions. By detecting the three states and developing corresponding control signals, counting circuitry may be utilized to determine the intensity with which the key is depressed to enable generation by a read-only memory of digital scaling signals representative of the variations in amplitude of the initiated tone with respect to the intensity with which the key is depressed. An envelope control counter responds to the control signals and a variable rate clock to drive an envelope generating read-only memory to generate a digital envelope signal. A master frequency generator comprising an oscillator and divider circuitry is used to generate a digital pulse train representative of the frequency spectrum of the initiated tone. The digital scaling signal and digital envelope signal are combined in a multiplying digital-to-analog converter to obtain a corresponding composite signal. The composite signal is integrated to improve its analog characteristics and then it is applied to an output gate wherein it modulates the oscillating signal to produce an electrical signal representative of the initiated tone. The composite signal may be filtered and amplified by appropriate circuitry and then audibly reproduced by a loudspeaker. In the multiple-tone embodiments of the invention, multiplexers are utilized to reduce the amount of circuitry duplication and interconnecting wiring.

Electronic tone-generating system

The embodiment of the invention disclosed herein is directed to an electronic phonograph selector and memory system which enables the selection of records to be played after the proper amount of credits have been accumulated in a coin accumulating circuit. The system has a movable record carriage for placing a desired one of a plurality of records at a playing location. The record carriage is transported by receiving a drive signal indicating that a new carriage position is required. The code signal information is compared so that when the carriage is at its desired location the search signal is removed. The movable carriage has a position encoder so that binary code signal information corresponding to the various positions of the carriage can be detected and compared to the codes stored in a random access memory circuit.

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Tonawanda, NY, United States of America

Robert W Wheelwright