Abstract: A manually operated switch located on an electric guitar controls a remotely located tuning device through the existing guitar cable. Preferably, the switch is located in an adaptor which plugs into the audio output jack of the guitar and into which is plugged the guitar cable. Circuitry associated with the switch sends a control signal on the audio cable and circuitry located adjacent the tuner interprets the control signal for controlling the tuner.

Abstract: A reference frequency generator for a tuning apparatus comprising a variable frequency divider which frequency divides a source signal in accordance with frequency division data stored in one or more ROM's. The frequency division data comprises note data for specifying frequencies of respective notes in one octave of a musical scale, pitch deviation data for specifying pitch deviation of the respective notes in one octave with respect to the frequencies specified by said note data and tuning curve data for specifying tuning characeristics covering several octaves, so that the generator generates reference frequency signals representing various pitch deviations and tuning characteristics as well as a standard tuning pitch or characteristic.

Abstract: A tuning device for musical instruments including a high frequency oscillator having frequency controlled by a tone select switch and an octave select switch and the output S.sub.H of which is supplied to the input of an AND-gate, the output of which is supplied to the display device for the tone pitch and the other input of which is connected to the output of a reference time signal generator which comprises a flip-flop for a wait signal S.sub.W and which is started by the amplitude of the tone via a microphone, an amplifier, a filter, a smoothing device and a Schmitt-trigger, and which is stopped after the counting of a definite number of tone oscillations filtered and converted into rectangular pulses. The opening time of the gate is preset by external oscillation with an internal oscillation, the frequency of which is started depending upon the frequency of the tone to be measured.

Abstract: A combined pick and stringed instrument tuning device includes a relatively flat, substantially rectangularly shaped housing having a pick attached thereto and is small enough to be easily held in one's hand. A momentary contact push-button switch mounted on top of the housing controls an electronic tuning circuit by selecting one of several predetermined frequencies from a frequency generator. In one embodiment, the tuning circuit is mounted in the housing so that the tuning device is totally self-contained. Alternatively, the tuning circuit is remotely located and is controlled by a cable connected to the housing or by radio signals. The frequency selected is displayed on the housing and the frequency generator drives a strobe light located near the pick. In another embodiment, a microphone mounted on the housing converts sounds from the string being tuned to a signal which is compared to the preselected frequency.

Abstract: In an electronic musical instrument apparatus is provided for generating musical sounds having a fundamental frequency which tracks the fundamental frequency of a time varying external control signal. A matched filter is used to generate frequency control signals which are determined by a closeness criterion between the external control signal and an internally generated test signal. Provision is made for offsetting the generated musical sounds for a preselected musical interval from the fundamental frequency of the external control signal.

Abstract: Tuning apparatus wherein the instantaneous deviations of a measured sound frequency from a reference sound frequency are averaged to display a mean deviation, thereby to improve the stability of the display. As a display unit, preferably a multidigit segment type display unit is used. The deviation data of the sound is visibly indicated as a positional shift of display elements in the display unit. The tuning apparatus can contain a timepiece therein. A reference frequency oscillating source and the display unit are used as constituents common to the tuning apparatus and the timepiece, whereby a timepiece-containing tuning apparatus which is small in size and light in weight is realized.

Abstract: An electronic tuning aid with luminous digital readout adapted by structural and functional features to be operational by placement on the body of string and musical instruments such as the guitar. A shiftable photoelectric probe constituting a unitized component of the device is of an optical character uniquely sensitive to both damped and undamped string vibration of slight amplitude to activate included solid-state counting and translating components affording a numeric display of the frequency of individually selected strings. Steel strings are automatically driven in sustained vibration by an electromagnetic drive system affecting only the selected string and timed by such string in a feedback circuit with the probe.

Abstract: An electronic tuning device provides four different modes of operation. In a first mode, the device sounds one of a plurality of internally generated audio frequency pitch standards that is manually selected by an operator for audible comparison with a note played on the instrument to be tuned. In a second mode, the manually selected, internally generated frequency pitch standard is compared with the note played on the musical instrument to be tuned and any deviation in frequency is visually displayed by a beat frequency indicator. In a third mode, the device automatically tracks an incoming note played on the musical instrument, compares such note with the internally generated frequency pitch standards and sounds the pitch standard that is closest in frequency to the incoming note.

Abstract: A plurality of a signal peak detection circuits connected in cascade for operation on a complex waveform input signal, for generating a reference signal having peaks occurring in time with the peaks of the fundamental frequency component of the input signal. The reference signal is processed for producing a voltage proportional to the period between successive signal peaks, which voltage is successively stored and monitored at select times for comparison of the relative magnitude changes in the voltage, for updating an output control voltage.

Abstract: An electronic automatic musical tuning device whereby an incoming tone from a musical instrument is picked up by a microphone, amplified and transformed to a square wave signal and compared in a phase locked loop with a progressive series of standard frequencies until matching occurs and the loop is locked to enable a display of the tone in a convenient output such as a row of lights.

Abstract: Instant scale shifting by predetermined increments is provided in a musical instrument tuning device by means of a programmable phase locked loop and crystal-controlled oscillator combination. The incremental scale steps are extremely accurate without need for recalibration and with no change in the tone intervals.

Abstract: The invention comprises a method and apparatus for the tuning of a piano and other similar musical instruments to equal temperament. A transducer is operative to receive two notes being struck, one of which is tuned and the other of which is to be tuned. The electrical output signal provided by the transducer is processed by bandpass filtering to isolate a predetermined beat note which is associated with the two notes being struck. The filter output signal is applied to an output transducer such as headphones which provides an audible rendition of essentially only the intended beat note.

Abstract: A device for the measurement of the number of cycles or half-cycles of a tone by counting the cycles during a reference time which is proportional to the cycle time of the tone to be measured, comprising a store for the cycle times, a comparator, a subtraction device in which a constant value is subtracted from the counted number of tone cycles, decoders, displaying devices for the oscillation error and the polarity sign, a retriggerable mono-flop for the oscillation existence signal, a flip-flop for a wait signal, a mono-flop for a read signal and logic elements for enabling the oscillation counter and the reference pulse counter.

Abstract: A transducer produces an electrical signal representing the frequency of a tone produced by the vibrating string of a musical instrument. Circuit means convert the electrical signal into a visually perceivable form which moves or appears to move in unison with the vibrating string. The signal from a frequency generator representing the desired frequency operates a strobe light source which is operatively associated with the visual vibrating motion display. When the string is in tune with the pre-selected desired frequency from the generator, the vibratory motion appears to stop and the strobe light or vibrating element appears to stand still.

Abstract: An automatic tuning device for use in a synthesizer of an electronic musical instrument in which an error signal is produced corresponding to an output tone signal from each of a plurality of voltage controlled oscillators and added to the input thereto for automatic tuning.

Abstract: A tuning device for musical instruments, which includes: harmonic filters for the prevention of zero transits of the tone frequency voltage extraneous to the fundamental tone oscillation or to the second or fourth harmonic, a Schmitt-trigger for the conversion of the filtered tone frequency voltage into a digital oscillation, an oscillation counter with decoder and display means to the input of which the digital oscillation signal together with the reference period signal is fed via an AND-gate and which is reset by the signal for lacking amplitude of the tone frequency voltage, a reference frequency source, a reference period generator, triggering means for triggering the reference period generator, a flip-flop for the generation of an oscillation period signal, and a synchronizing device for synchronizing the beginning of the counting period with the reference frequency voltage.

Abstract: A pitch bend apparatus for electronic musical instrument having a voltage-controlled oscillator that works as a tone generator is provided with a first variable resistor for operating the pitch bend as well as a second variable resistor for setting a varying width of pitch bend or a maximum amount of pitch deviation. The varying width of the pitch bend is controlled by connecting the first and second variable resistors into an amplifier circuit to control the gain thereof, or by controlling the voltage applied to the first variable resistor by means of the second variable resistor.

Abstract: A keyboard controlled just intonation computer for electronic organs which automatically responds to correct the larger tuning errors of equal temperament as each interval or chord is played. The logic circuit for this purpose has twelve inputs corresponding to the twelve notes of the chromatic scale. The logic circuit can be interfaced with the keyboard by utilizing keyer voltages from octavely related key switches fanning into each input of the logic circuit through a diode branch circuit. Each of the twelve master oscillators of the organ has a two input tuning means adjusted to lower the frequency of the master oscillator by one seventh of a semitone if one input is energized by an output of the logic circuit or by three tenths of a semitone if the other input is energized. The smaller pitch shift is required for the top notes of major thirds or major sixths, or for the bottom notes of minor thirds or minor sixths.

Abstract: In an electronic musical instrument with two tone generators of which the frequency of the tones produced by them is substantially constant for the first generator a priori and for the second generator not until after a final value is reached which corresponds to the frequency of the corresponding tone of the first generator, the frequency of the first generator is applied to a first input and that of the second generator to a second input of a frequency comparator circuit, whose output is connected to a control input of the second generator via control device. This ensures that the repeated readjustments of the control quantities necessary in known instruments are no longer necessary.

Abstract: Switching means for automatically determining which note in the entire musical spectrum is closest to an input frequency and display means for generating a visual display of the frequency difference between said input signal and the correct frequency of said note, specifically adapted for the tuning of musical instruments.

Abstract: An apparatus for the automatic tuning of an electronic musical instrument comprising a phase comparator, a converter circuit connected to the comparator for converting an output signal of the phase comparator into a voltage of a magnitude corresponding thereto, a sample hold circuit connected in series with the converter circuit, a calculation circuit having a first input connected to the sample hold circuit and a voltage control type oscillator for generating a musical tone signal connected in series with the calculation circuit. The voltage control type oscillator is connected to an input of the phase comparator and another input of the phase comparator is connected to a circuit for producing a standard signal.

Abstract: An electrical musical instrument is provided with a tone generator comprising a plurality of vibratory tone bars each supported with its both ends free. The tone bars are struck by key-actuated hammers and the vibration of each tone bar is picked up by a mechanical-electrical transducer associated with the tone bar. With such tone generator, the tone produced by the musical instrument of this invention is very much improved, especially in that the tone is rich in a solid and percussive constituent.

Abstract: A method and an apparatus for adjusting the vibration frequency of vibrating objects such as piano strings, by stepwise adjustment of the vibration frequency of a vibrating object. The amount of the required adjusting operation in each of the adjustment steps is calculated by the equation:.DELTA..theta..sub.i = K.sub.i (f.sub.s - f.sub.pi-1)wherein:i represents an integer such as 1, 2, 3, ...;.DELTA..theta..sub.i represents the amount of adjustment in the i-th adjusting step;f.sub.pi -1 represents the vibration frequency after the (i-1)th adjusting step;K.sub.i represents the constant employed in the calculation of the i-th adjusting step;The constant (K.sub.1) for the initial (i=1) adjusting step is predetermined; andThe constant K.sub.i (i=2, 3, ...) for the second and subsequent adjusting steps is calculated by the equation: ##EQU1## WHEREIN: .DELTA..theta..sub.I-1 REPRESENTS THE AMOUNT OF ADJUSTMENT IN THE (I-1)TH ADJUSTING STEP;f.sub.

Abstract: A color organ device for producing a visual display of lights responsive to electrical signals produced on respective channels of a four-channel stereo. The device includes a housing having a plurality of banks of lights therein which is rotated by an electric motor. A interpreter is provided for selectively separating the frequencies produced by the four-channel stereo for selectively energizing the banks of lights. Slip-rings are provided for making electrical contact between respective frequency discriminating circuits and the banks of lights.

Abstract: An electronic musical instrument includes an oscillator for generating a signal at a frequency corresponding to that associated with a depressed key of the keyboard. The key selects a control voltage, from an exponential voltage divider, for controlling the frequency of a voltage controlled oscillator, which produces a frequency which is directly proportional to the control voltage and inversely proportional to a reference voltage. The reference voltage compensates for variations in the level of the supply voltage, so that the oscillator frequency is independent of the supply voltage.

Abstract: An Electronic Tuning Device for tuning musical instruments employes a single radio frequency oscillator. Frequency dividers are used to divide the frequency of the radio frequency oscillator (clock) by various divisors so as to produce a series of notes that approximate a desired musical scale. A note selector selects a particular note for use as a reference frequency against which a musical instrument to be tuned can be compared. The note selector also controls means for shifting the frequency of the master oscillator slightly so as to place the frequency of the selected note exactly at its proper position in the desired musical scale. A vernier control is provided by means of which the master oscillator can be altered so as to cause all of the notes to be sharped and flated up to about a half semitone.