Abstract: An amplifier circuit which amplifies an input signal with substantially zero distortion and can stably operate even at high frequencies is provided. A signal proportional to an input signal supplied to an input terminal is applied to an input terminal of a main amplifier. An output signal of this main amplifier is supplied through an impedance circuit to one of input terminals of a differential amplifier the other input terminal of which is supplied with the input signal to be amplified. An output signal of this differential amplifier is fed to a reference voltage input terminal of the main amplifier to determine a voltage potential of the input terminal of the main amplifier when a signal level of the input signal is zero, thereby distortion generated in the main amplifier being canceled.

Abstract: A bottom closure for resonator of a sound bar on percussive musical instruments has a radially expandable construction for uniform pressure contact of a gasket with the resonator inner wall. Ideal follow-up of the bottom closure to the current shape of the resonator bottom end resulted from its elastic deformation assures almost perfect air leak prevention under any conditions.

Abstract: A modulation effect device for use in an electronic musical instrument which utilizes, as a digital modulation circuit, a digital memory device for storing digitized musical tone signals. The digital memory device is accessed by modulation coefficient generating means which supplies a modulated address information to the digital memory device to read out from the memory device a musical tone signal modulated in accordance with the modulated address.

Abstract: A disc centering device for centering an information carrier disc having a central aperture in a disc player. A turntable has a cylindrical wall provided at the center portion thereof to guide the information carrier disc to fit therearound. A disc rest portion is formed around the cylindrical wall and supports the information carrier disc. A clamping mechanism is provided for clamping the information carrier disc in cooperation with the disc rest portion of the turntable, the clamping mechanism being movable against the turntable, and the information carrier disc is clamped between the clamping mechanism and the disc rest portion. A centering mechanism is provided for centering the information carrier disc with respect to the turntable by contacting the periphery of the central aperture of the information carrier disc when the information carrier disc is clamped by the clamping mechanism.

Abstract: A variable resistance circuit comprises first and second transistor pairs, first and second load circuits connected to respective collector sides of the first and second transistor pairs, and first and second constant current sources connected to respective common connected emitters of the first and second transistor pairs. Each of the load circuits supplies collectors of each transistor pair with currents having same current values with each other. Each of the constant current sources supplies the common connected emitters of each transistor pairs with a constant current. Respective base and collector of one transistors of the first and second transistor pairs are connected to each other and connected to first and second terminals, respectively. Bases of the other transistors of the first and second transistor pairs are connected to the second and first terminals, respectively.

Abstract: An automatic playing musical instrument is provided in which the amount of storage medium to be used is substantially decreased. The automatic playing musical instrument is provided with a key information generating circuit for generating key information corresponding to a depressed key among the plurality of keys. A change of the key information is then detected, and a time interval between one of the change and the other which follows immediately after the one of the change is measured so as to generate a time period data representative of the time interval. Each time the change is detected, a musical performance data comprising the key information and the time period is stored in the storage medium, while on the other hand if the change is not detected, no musical performance data is stored thereby saving the amount of the storage medium to be used.

Abstract: Plural channels of tone generation capable of selectively generating plural kinds of waveshape signals are provided. A waveshape signal to be selected in each of the channels is designated in accordance with the tone pitch or tone range of a tone to be generated and waveshape signals which differ from each other between the channels are respectively generated. The different waveshape signals of the respective channels are weighted by scaling parameters according to the tone pitch. A circuit capable of providing the waveshape signal with amplitude envelopes which differ from each other between the channels is further provided and selection between imparting of such envelopes and weighting in accordance with the scaling parameter is made in response to a tone color. A plurality of tone synthesis systems having the tone synthesis function described may be provided and tone signals obtained in the respective systems may be added together.

Abstract: A diaphragm of a loudspeaker is made up of a plurality of laminated composite sheets each including a number of fibers, for example, carbon fibers having a high Young's modulus to density ratio, and a matrix bonding together the fibers. Each composite sheet is divided into a plurality of adjoining sections formed by dividing the composite sheet about the center axis of the diaphragm. The divided composite sheets are laminated such that joints between adjacent sections of one composite sheet do not overlap joints between adjacent sections of the other composite sheet. In other embodiments a similar composite sheet is spirally bonded to the outer surface of the diaphragm or rings having different diameters and made of similar composite sheet are coaxially bonded along the outer surface of the diaphragm.

Abstract: A digital electronic musical instrument is constituted by detector, a phase angle, information generator and a musical tone generator. The detector detects an end portion of a period of a musical tone to be produced. The phase angle information generator repetitively generates phase angle information representing an instantaneous phase angle of the musical tone during from start to end of the period of the musical tone in response to the detection of the end portion of the period. The musical tone generator synthesizes the musical tone in accordance with the phase angle information. Operations of the detector, phase angle information generator and tone generator are performed on the basis of clock pulses having a predetermined frequency which is an integer multiple of a fundamental frequency of the musical tone to be produced, thereby realizing the so-called pitch synchronous system and simplifying the construction of the musical instrument.

Abstract: A power amplifier with a low distortion and a high power efficiency includes a first amplifier of the low distortion type for being powered by a first voltage source to amplify an input signal thereto to apply an output signal to a first terminal, and a second amplifier of the high power efficiency type for being powered by a second voltage source to amplify the input signal to apply an output signal to a second terminal. A load is connected between the first and second terminals. The output voltage of the second voltage source is greater than that of the first voltage source. A first feedback path is provided for feeding back the output signal of the first amplifier to an input thereof. A second feedback path is provided for feeding back the output signal of the second amplifier to the input of the first amplifier.

Abstract: An automatic focusing device in an optical type data reproducing apparatus is capable of restoring an objective lens to a position in which a servo controlling system can perform a normal servo control, when the servo controlling system has entered a divergent state. In the device, a photodetector produces a detection signal corresponding to a relative distance between the objective lens and a disk and, in response to this detection signal, the servo controlling system automatically controls the relative distance between the objective lens and the disk so as to form a focal point on a signal plane of the disk.

Abstract: Analog output signals of a key touch sensor and tonal effect setting manual operators are respectively time division multiplexed and thereafter are converted to digital signals by using an analog to digital converter on a time shared basis. The key touch sensor capable of detecting a key touch of a depressed key can also be used for obtaining an initial touch detection signal by additionally providing a device for holding a peak value of an output signal of the sensor at the beginning of depression of the key. Control factors of various tonal effects are controlled in response to these converted digital signals. Control factors of an attack pitch control effect are controlled in response to the key touch. In imparting a delay vibrato effect, the attack pitch control is automatically applied before the delay vibrato is initiated. In imparting a vibrato effect, the attack pitch control is automatically applied and the vibrato is applied thereafter if a key has been depressed in a staccato form.

Abstract: A stabilizer to be attached to the handle raiser of an archery bow is disclosed. The stabilizer includes a pair of laterally extending arms constructed and arranged to be flexible in the shooting direction. Flexing of the arms is mechanically restricted in the shooting direction by the use of a rigid backing overlying a portion of each arm. By mechanically restricting the flexing of the arms, the inertia created is maximized for pushing the archery bow towards the target at release of an arrow.

Abstract: A digital filter imparting a desired tone color to the tone signal is realized by the combination of a digital pole filter and a digital zero filter capable of controlling a pole and a zero in an amplitude-frequency characteristic respectively. The amplitude-frequency characteristic of the digital filter is a composite of the respective characteristics of the pole filter and the zero filter. A "peak" portion and a "valley" portion in this composite characteristic can be set independently by the pole control of the pole filter and the zero control of the zero filter, whereby the desired tone color characteristic can be readily realized. Further, the digital filter may comprise a plurality of digital filters having respective different constructions and a connection switching circuit capable of setting arbitrarily connection between these filters. The filter characteristic as a whole can be diversely altered by changing the connection, whereby diverse tone color characteristics can be realized with ease.

Abstract: This electronic musical instrument has plural operation units respectively performing a predetermined basic waveform generation operation (e.g., frequency modulation operation) using a phase signal representing a pitch of a tone to be produced or a waveform signal generated by the operation unit. There is further provided a setting section for variably setting a combination of input and output connections between the respective operation units as freely as the performer desires. The input and output connections between the operation units are switched according to the set combination. An operation algorithm for tone synthesis is determined according to the combination of connections between the operation units set in this manner whereby a free tone synthesis as desired by the performer is realized. A display is provided for visually indicating the set combination of connections and a state of connection between the respective operation units is indicated as a graphic pattern on this display.

Abstract: An automatic rhythm performing apparatus capable of producing a rhythmic tone of a plural-tone-source rhythmic musical instrument such as a snare drum comprises a plurality of signal producing devices which produce a plurality of rhythmic tone signals corresponding to the respective tone sources of the single instrument. A control device controls respective signal levels of the rhythmic tone signals and a combining device combined the rhythmic tone signals at signal levels controlled by the control device to provide a combined signal corresponding to the rhythmic tone of the instrument, thereby providing a desired volume relationship of the respective component tones constituting the whole rhythmic tone of the instrument.

Abstract: An electronic musical instrument is of a type in which tones are produced by a limited number of tone production channels which are efficiently used for a larger number of tones utilizing channel assignment technology. Normally, three of the channels are exclusively occupied for production of three tones to constitute a triad chord. But at time a bass tone is to be produced, the specific one of the three channels is compulsively used for production of the bass tone, giving up exclusivity for production of the chord tone. This eliminates the need of providing an additional channel for the bass tone production.

Abstract: In an electronic musical instrument comprising a keyboard including a plurality of keys, a tone signal generator for producing a musical tone signal corresponding to a depressed key, a key touch detector for generating a key touch signal concerning a key depression operation of the depressed key, and an operator for controlling one of musical tone components of the musical tone signal, there are provided a selector for selecting either one of two control elements comprising the operating state of the operator and the key touch state at the time of key depression for determining whether the degree of control of the musical element caused by the selected control element is to be emphasized or not, and a suppression circuit for inhibiting or suppressing the musical tone control effected by the other control element in accordance with the state of selection of the selector.

Abstract: An electronic musical instrument comprises a keyboard, a tone generator and a digital filter. The tone generator bit-serially generates a musical tone signal corresponding to a depressed key on the keyboard. The digital filter bit-serially performs a digital filtering operation of the musical tone signal in accordance with the predetermined amplitude-frequency characteristic. A musical tone is produced based on an output of the digital filter, whereby the characteristic is imparted to the musical tone. This bit-serial processing in the digital filter makes not only the circuit construction of the digital filter itself but also that of the electronic musical instrument incorporating this digital filter smaller and simpler.

Abstract: A device for detecting a key switch operation capable of detecting an operating state of a plurality of key switches which are commonly connected with respect to each row line (block line) at one terminal thereof and commonly connected with respect to each column line at the other terminal thereof, thereby constituting a switch matrix. If a signal is provided on all column lines, the signal is transmitted to a block line through a key switch which is in operation and thereby a block including the key switch in operation is detected. A signal is then supplied from the detected block line to a column line only through the key switch in operation in the detected block. The position of the key switch in operation is known by detecting the columnn line on which the signal arrives. According to an embodiment of the invention, capacitance elements are provided both on the block lines and on the column lines for effecting delivery of the signal by charging and discharging of these capacitance elements.