Abstract: In an electronic organ of the time-sharing type, a single clock source drives a number of variable divisor frequency dividers which are assigned different divisor values to produce different musical tones at different times. In order to prevent phase synchronism between two simultaneously operating dividers, and thus achieve a rolling phase relationship which is perceived as a chorus effect, divisor values are employed for the two frequency dividers which are not in a whole number relationship. If the two dividers are generating octavely related notes, the divisors used have a ratio not quite equal to the nominal 2:1 value which musical theory requires. Moreover, the exact value of the ratio varies from note to note within each octave so that the rate of phase roll is not monotonously the same for all notes. Alternatively, if the two dividers are both generating the same note, then the divisors used have a ratio which is not quite equal to the 1:1 value which musical theory requires.

Abstract: A reverberation sound producing apparatus includes a nonuniformly tapped delay line, a summing circuit applying an audio signal to the input of the tapped delay line and a feedback path coupling the output taps of the delay line back to its input through the summing circuit. A separate output path couples the reverberation signal from the feedback path to an output amplifier and speaker system. The feedback path is adjusted for minimizing loop gain and the effect of ripple in the frequency response of the delay line while the output path is adjusted for providing a smoothly decaying reverberation signal.

Abstract: A data encoder for use with a time multiplexed electronic organ or the like comprises a multiple stage shift register, means for simultaneously loading a predetermined pattern of logic bits in the shift register in response to a key down representative data pulse and means for coupling the output of the shift register to one of the data channels of the organ. In a first mode, the data encoder is operable as a fill-note generator wherein the shift register is loaded in response to an upper manual key down representative data pulse and lower manual key down representative data pulses are coupled to the upper manual data channel of the organ according to the output of the shift register. In a second mode, the data encoder is operable as a chimes generator wherein the shift register is loaded in response to an upper manual key down representative data pulse and the output of the shift register is coupled to the upper manual data channel of the organ.

Abstract: A guitar or other fretted stringed musical instrument includes intonation adjustment means comprising an aperture underlying a string at the instrument's bridge and a saddle rotatably received within the aperture. The saddle carries a string supporting surface operable in a cam-like manner for adjusting the vibrating length of the string in response to rotation of the saddle within the aperture.

Abstract: A frequency divider circuit is selectively operable for providing an output signal characterized by a first frequency or a second frequency equal to one-half the first frequency. An input signal at the first frequency is supplied to the clock terminal of a D-type flip-flop and a stream of control pulses, developed in synchronism with the input signal, are selectively coupled by a logic circuit to the set terminal of the flip-flop. The D and Q terminals of the flip-flop are coupled together forming an output for providing a signal at the first frequency in response to the presence of the control pulses and at the second frequency in response to the absence of the control pulses.

Abstract: A tone generator for use with an electronic musical instrument includes a binary counter operated by a binary comparator and a source of clock signals for incrementally advancing or decreasing the state of the counter from a first selected state to a second selected state. The states of the counter control a programmable divider which develops corresponding output tone signals. The counter produces multiple state changes between the selected states so that each individual state change results in a frequency change which is inaudible. The overall effect is to thereby synthesize a tone signal creating the illusion of a continuous pitch change between the pitches corresponding to the selected counter states. The source of clock signals includes a rate multiplier programmed according to the states of the counter to compensate system operation for insuring that similar musical effects defined by corresponding musical intervals are produced in equal time intervals.

Abstract: A time-shared electronic musical instrument is provided with programmable wave-form generating and tone coloring circuits in order to maintain the musical characteristics regardless of pitch. The circuits comprise programmable keyers and wave-shapers, programmable envelope generators, programmable filters, and a programmable voicing selection circuit, in all of which certain characteristics of the output signal are tailored to the frequency of the musical tone.

Abstract: 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.

Abstract: A reversible bracket assembly for use with an electronic apparatus bearing housing or the like includes an elongate plate having opposed sides each suitably fastenable to the side panels of the housing. A mounting flange extends transversely of and integrally from one end of the plate and a handle member extends integrally from the other end of the plate. The plate is fastenable to the housing with one of its sides in abutment with the housing side panels for facilitating portable transportation and use of the housing by means of the handle members and with its other side in abutment with the housing side panels for facilitating mounting of the housing within a standard equipment rack through the agency of the mounting flange.

Abstract: In an electronic musical instrument of the type in which pitch selection is achieved by pulse position modulation, and a rhythm accompaniment is played automatically under the direction of a read-only memory, a shift register is used to create pulse position modulation instructions for harmonic footages of the fundamental note, and selected combinations of these footages are rhythm-modulated and rhythm-counter-modulated under the control of logic gates which are responsive to various manually operated stop tabs.

Abstract: A distortion sound effects circuit producing an output signal corresponding to an input signal but containing one of four selected types of distortion. A compressor which includes a voltage-controlled amplifier first compresses the audio input signal within preselected limits, and the distortion operations are performed on the compressed audio signal to advantageously render the subsequent distortion operations insensitive to gross amplitude fluctuations of the input signal. The compressor includes means for full-wave rectifying the compressed audio signal. The full-wave rectified signal is provided as a distorted output signal containing hard-even distortion of the type commonly achieved by severely, asymmetrically clipping a signal. A distortion circuit includes single voltage controlled square-low amplifier to which the compressed audio signal is applied performs the other three types of distortion.

Abstract: A programmable dynamic filter for use with a time-shared electronic organ or the like includes a filter circuit responsive to a logical state of a control signal for tracking notes generated by the instrument. Means are provided for programming the filter independently of generated notes by selectively adjusting the pulse width of the control signal to achieve desired musical effects.

Abstract: A switch mechanism designed to overcome the problem of electrical noise employs a compound movable contact assembly, including a coil spring member and a smooth-surfaced wire contact member mounted thereon. The flexing of the coil spring provides an advantageous rolling, wiping motion for the wire contact member, without the noise-producing electrical discontinuities associated with earlier mechanisms in which the coil spring itself made direct electrical contact.

Abstract: This invention relates to an electronic pickup system for a stringed musical instrument. The system includes three pickup coils positioned under the instrument strings and oriented one behind the other along the length of the strings. Each of the coils is wound around a coil form in a predetermined direction and has a selectively poled magnet passing through its center. The coils are selectively electrically connected, at least two at a time, to each other and to the system output. The manner in which the coils may be connected include connecting any two of the coils in a maner such that signals induced in the coils as a result of string vibration are in phase, at at least selected frequencies, and thus additive. The coils normally are also connected in a manner such that noise signals induced in the coils are out of phase and therefore cancel.

Abstract: An automatic rhythm generator of an electrical musical instrument including a rhythm pattern generator for rhythmically selecting for actuation different ones of a plurality of instrumentation circuits to be sounded and a strobe pulse generating circuit for establishing the appropriate pulse width of a drive pulse needed by each instrumentation circuit for proper actuation thereof. The rhythm pattern generator circuit selectively enables a plurality of drive gates respectively associated with the plurality of instrumentation circuits during selected ones of a succession of periodic rhythm cycles in accordance with a predetermined rhythm pattern. The strobe circuit is synchronized with the rhythm pattern generator and generates during each rhythm cycle a plurality of strobe pulses on a corresponding plurality of outputs respectively associated with the plurality of instrumentation circuits. Each of the strobe pulses has a width preselected for the instrumentation circuit with which it is associated.