Norlin Industries, Inc.

Norlin Music, Inc.

Douglas R Moore

Alberto H Kniepkamp

Richard S Swain

Glenn M Gross

Eugene S Morez

This is an electronic organ which economically simulates long duration aperiodic musical waveforms, such as the clash of cymbals. It employs the digital waveform generation technique, in which successive instructions are read out of a memory to determine the amplitude of the waveform at successive sample points. To save memory capacity, the memory addresses are rescanned; and to avoid audible discontinuities the scan direction recirculates numerically back and forth across the address field. Despite the bidirectionality of the scan, monotonic decreases in amplitude and in higher harmonic content are achieved. The monotonic decrease in amplitude is accomplished by impressing an exponentially declining envelope upon the digitally generated amplitudes. The monotonic decrease in higher harmonic content is accomplished by preventing the rescan from returning to a memory region of greater harmonic content after it has once entered a region of lesser harmonic content.

Long duration aperiodic musical waveform generator

Apparatus for producing a chorale or vocal effect in an electronic musical instrument comprises means responsive to the playing keys of the instrument for producing an indexing signal and means responsive to the indexing signal for sequentially developing a plurality of control signals. A programmable filter is responsive to each sequentially developed control signal for modifying the harmonic content of a tone signal to simulate a different vowel-like sound for producing a vocal effect consisting of a sequence of different vowel-like sounds as the keys are played. The modified tone signal may be coupled through a chorus generator to simulate a chorale effect and the programmed characteristics of the filter may be modulated to further animate the performance as well as being made responsive to a glide signal for producing two different vowel-like sounds in succession at two different pitches in response to a glissando or portamento command.

Vocal effect for musical instrument

An electronic musical instrument includes a programmed microprocessor for controlling selected functions of the instrument and a plurality of key and tab switches responsive to a scan control signal repetitively scanning the switches for developing a serial data signal defining operated key and tab switches during each of the scans. An interface circuit is interposed between the key and tab switches and the microprocessor for developing the scan control signal and for receiving the resulting serial data signal. The serial interface circuit includes means for converting the received serial data into a number of first multibit words each representing a depressed key and a number of second multibit words each bit of which represents the operational condition of a respective one of the tab switches. The first and second multibit words are stored in a RAM in a compressed format, the RAM being enabled for coupling its contents in parallel form to the microprocessor in response to two consecutive scans of the key and tab switches resulting in the development of identical serial data signals immediately preceded by a scan resulting in the development of a serial data signal different therefrom. The interface circuit also includes means for converting data words coupled to the RAM from the microprocessor into a corresponding serial data output signal.

Serial interface circuit for an electronic musical instrument

An improved system for increasing the loudness of any single note selected by playing more than a single key. A command circuit responsive to manual control, including stop tabs, enables a tone signal to be produced in response to the playing of one key or in response to the simultaneous playing of a plurality of keys on a keyboard. Means are provided for changing the relative amplitude of a tone signal produced in response to the simultaneous playing of a plurality of keys with respect to the amplitude of a tone signal produced in response to the playing of a single key.

Apparatus for reinforcing notes selected by more than one key

This is an electronic organ drawbar circuit in which selection of the footage volumes is accomplished by means of a switch matrix; and sets of footage/volume correlations so chosen are stored in a memory. Another group of switches is used to select among several different memory fields, so that various sets of footage/volume data can be stored while another set of data is in use, and each stored set can be recalled for subsequent re-use.

Footage volume control circuit

This invention relates to tone generating systems for polyphonic electronic musical instruments. The system includes a plurality of programmable tone generators each of which is assigned to a different note to be sounded. For a preferred embodiment, one of the programmable tone generators is designated as a solo high tone generator, and is always utilized to produce the highest note to be sounded. Another generator may be designated as the solo low generator, and will always be utilized to generate the lowest note to be sounded. Additional solo note generators may be provided if desired. Tone generators are interconnected in a priority scheme with one generator at a time being designated as the next generator to be assigned a note to be sounded, and the designation being advanced in a predetermined manner as notes are assigned successively to the generators. One or more keyers are associated with each programmable tone generator, and receive a keyer enable signal from the tone generator when a note to be sounded is stored therein. Each generator also generates one or more pulse code outputs to its corresponding keyers, programming them to adapt to the selection of musical notes over a multi-octave range. Phase cancellation between two notes which are octavely related is avoided by duplicate generation of one of the notes in both master and slave tone generators, the code for any note being stored in both the master and slave generators whenever it is determined that the code for an octavely related note is already stored in another master generator. Various special effects are achieved by selectively dropping pulses from the clock signal applied to the programmable divider of the generator.

Tone generating system for electronic musical instrument

The disclosure describes an improved electronic musical instrument capable of simulating a sound resulting from the striking of a natural percussion instrument. The electronic instrument includes playable keys, a tone signal generator for generating tone signals and an output circuit for converting the tone signals to audible tones. A control circuit responsive to the depression of any one of the keys enables one or more of the tone signals representing one or more fundamental pitches to be transmitted to the output circuit for a first time period and enables another tone signal representing a pitch nonharmonically related to the fundamental pitches to be transmitted to the output circuit for a second time period less than the first time period. By combining the tone signals corresponding to the fundamental and nonharmonic pitches, the sound of a percussion instrument is simulated.

Percussion simulating techniques

A circuit for producing a chorus effect in an electronic musical instrument. The circuit includes N separate channels, where N is an integer greater than one, with each channel having an analog delay line to which a tone signal is applied. Each delay line frequency modulates the applied tone signal at a subaudio rate in response to changes in the frequency of clock pulses applied to the delay lines. The delay variations in one delay line are out of phase with the delay variation in every other delay line by a selected amount which is normally 360.degree./N. Clock pulses are generated by means including a nonlinear circuit to compensate for the nonlinearity in the frequency interval between tones in the musical scale. The outputs from the delay lines after filtering of the clock frequency components are utilized to produce the desired chorus effect output from the instrument. Each of these outputs is applied through a separate voltage controlled amplifier (VCA) with a common control voltage being utilized for all of said VCA's. The magnitude of this control voltage is determined by the amount of light from a light source which impinges on a photo-resistive device controlled by a mask positioned between these elements.

System for producing chorus effect

An integrated circuit has a shift register, driven by a source of clock pulses, for sequentially energizing each of a set of selectively activated switches. Each of the switches connects an analog input signal to the input of an individual sample-and-hold unit, the outputs of which are available at output terminals of the circuit. The outputs of the sample-and-hold units represent the amplitude of the analog input signal, sampled at the rate of the clock pulses applied to the shift register. The analog input signals of selected outputs are modified selectively.

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Vernon Hills, IL, United States of America

Douglas R Moore