1,235,481. Signalling by audio-frequencies. BRITISH AIRCRAFT CORP. Ltd. 12 March, 1969 [19 Dec., 1967], No. 57589/67. Heading G4H. [Also in Division H4] In a system for signalling between a central station and a number of remote gun stations by radio telephone or over telephone lines the central station has a microphone and an encoder adapted to accept a decimal input and produce a binary coded output the "1" and "0" bits of which are represented by two audio-frequency tones, means being provided to transmit either the output from the microphone or the output from the encoder and means at the receiver to reproduce either speech or the original decimal input. The decimal input, from a computer for a keyboard, is applied to the encoder and a switch passes it to the transmission circuit. The signals are gated into a shift-register in the encoder under the control of clock pulses. A counter gives a signal when the message is complete to switch the transmission back to the microphone. At the gun station the two frequencies are separated by filters, the output of the "1" filter being applied to a call recognition circuit which enables the decoder. This comprises a shift register into which the incoming serial signals are shifted under the control of clock pulses derived by combining the outputs of the "1" and "0" filters. The output of the shift register is recoded from binarycoded-decimal form into decimal form and displayed on indicators showing the azimuth and bearing to which the gun is to be laid. Speech signals are reproduced on a speaker.

Information transmission system

An electronic organ includes logic and a memory for detecting and storing a root note signal identifying a chord which has been either automatically or manually generated. Priority logic, coupled with the memory, passes the lowest root note signal to a tone selection matrix which passes a plurality of tone signals representing the note intervals forming the selected chord. A sequential gating circuit receives all of the tone signals and is responsive to an arpeggio circuit, a strum circuit, or a rhythm unit to gate selected tone signals, one at a time, to the voicing circuitry. When one or more of the tone signals are octavely displaced within the selected chord, disinverting gates are enabled to unfold the chord and cause the tone signals to occur in order of ascending frequency.

Electrical musical instrument with chord generation

A musical instrument incorporates apparatus for automatically producing an arpeggio, successively producing tone in accordance with operated keys of a keyboard, in response to operation of at least one control switch. Switches operated by the keys are scanned by a scanner, and the several tones of the arpeggio are each produced by a predetermined time, by stopping the operation of the scanner as the switches corresponding to operated keys are reached in each scanning cycle. The stopping of the scanner is under control of a multivibrator having an adjustable period, to permit manual selection of the rate at which the arpeggio is produced. A plurality of mode selector switches are operable to select the mode of operation of the scanner. An arpeggio having tones extending over a range of one, two or three octaves is selectable by the mode selector switches, and the mode selector switches are also operable to select one of a variety of styles of arpeggio, including an ascending style, a descending style, and a style in which the arpeggio alternately ascends and descends. A foot switch is provided for initiating the arpeggio.

Musical instrument having automatic arpeggio system

An electronic musical instrument incorporates a single integrated circuit chip for performing a variety of logical operations for the production of chords and various accompaniment signals automatically, in response to depression of one or two keys within a related portion of the keyboard of the instrument. A multiplexer is employed, in association with the keyboard, to produce a train of signals in response to depression of one or more keys, and one or more function control switches; certain ones of these signals are used to address a plurality of read only memory devices for the generation of the several components needed for the mode of operation which is selected. In an automatic chord mode, a chord is selected automatically, corresponding to an operated key of the keyboard. The chord components include the root, the third (which may be selectively minored), the fifth, the sixth and the seventh (which can be selected or not). The several chord components are mixed in a stair step network for one output signal, amd may selectively be produced individually for an arpeggio or a strum or both.

Electronic musical instrument with means for automatically generating chords and harmony

Electronic and logic circuitry for an automatic tonal bass rhythm accompaniment feature and an automatic chord feature in an electronic organ. Automatic bass rhythm accompaniment produces a pattern of notes based upon a tonic note selected by the instrumentalist such that the desired musical effect is produced when the pattern of notes is combined with the notes being played by the instrumentalist. The electronic organ has stored in a memory various rhythm patterns which can be selected by the instrumentalist by closing rhythm switches. Electronic circuitry then causes notes for the selected rhythm pattern or patterns to be played automatically in response to the actuation of a pedal switch or keyswitch. The automatic chord feature of the present invention provides selectively major triad and dominant seventh chords or minor triad and diminished seventh chords automatically in response to the selection of a root note by the instrumentalist.

Automatic control apparatus for chords and sequences

An electronic chord organ, in which voltage controlled oscillators are each supplied with the same voltage, the voltage being selected by actuation of keys of an organ keyboard, and the currents supplied to the individual oscillators being selected to sound a musical chord. The voltage controlled oscillators each receive voltages from a resistive voltage divider via a voltage sample and hold circuit, key switches applying voltage from selected points along the voltage divider via diodes to a common bus, the bus controlling the frequencies of all the oscillators, and the diodes serving to render only one key switch operable to apply voltage to the bus when plural ones of the key switches are simultaneously closed.

Bunger D

Papers

Voltage controlled chord organ