In an audio signal level control circuit for use in an audio system such as an electronic musical instrument, which comprises an emitter-grounded type transistor amplifier, an input signal being applied to the base and an output signal being taken out from the collector, a constant-current supply circuit including another transistor and being connected in series in the emitter path of the amplifier, and a field effect transistor (FET) connected between the emitter of the amplifier and the ground...

Keys of a keyboard are divided into a plurality of tone ranges and a plurality of musical tone waveforms regarding specific ones of the divided tone ranges are stored in a waveform memory device. A number of the plurality of musical tone waveforms is smaller than the number of the divided tone ranges. An address signal generator is provided which generates an address signal having a repetition period corresponding to a tone pitch of a depressed key and supplies the address signal to the waveform...

An electronic musical instrument includes a plurality of address generators for producing address signals corresponding to different tones each varying at a rate synchronous with the frequency of each of the different tones, a waveform memory device including a plurality of addresses for storing at respective addresses a plurality of waveform sample values that constitute a waveform, a circuit for sequentially supplying one after another of the address signals to the waveform memory device to re...

An electronic musical instrument includes twelve multiplexed wave data generators each of which corresponds to one of twelve musical notes in an octave and produces a multiplexed wave data signal which has a basic pulse frequency decisive of a note and has data indicating states of octavely related plural waves for the same note in a time-division-multiplexed manner. A note selection circuit selects a multiplexed wave data signal for the note designated by the depressed key. The selected wave da...

An electronic musical instrument are provided a plurality of tone production channels to produce musical tones polyphonically. Each of the tone production channel includes a first counter which divides clock pulses by either one of N and N+1 to deliver an output pulse. A second counter and a control circuit are further provided in the instrument, which are commonly used for respective tone production channels. The second counter counts, on the time division basis, the output pulses from the firs...

In a method and a device for accessing an optical disc such as a Compact Disc, a CD-ROM, a CD-I and a MD, an optical disc in which data is recorded or to be recorded at a constant linear velocity is rotated at a substantially constant number of revolution per unit time and this optical disc is accessed on the basis of a clock signal which changes its frequency in accordance with an access position (i.e., a read position or write position). Since random accessing is made in a state in which the o...

A key-speed-responsive volume control apparatus for a keyboard-type electronic musical instrument includes a key switch associated with a key of the instrument, wherein a movable contact of the key switch moves out of engagement with a break contact and into engagement with a make contact upon depression of the key. A capacitor is charged following the movement of the movable contact out of engagement with the break contact and before engagement with the make contact. The capacitor is made to di...

A plurality of waveshape memories are provided for storing the sampled values of one cycle sinusoidal wave as the fundamental frequency, two cycle sinusoidal wave as the second harmonic, . . . and m cycle sinusoidal wave as the m-th harmonic and, in addition thereto, of harmonic-abundant complex waves such as a triangular wave, a sawtooth wave and a rectangular wave. These waveshape memories are read at the same reading rate. The read out sinusoidal waves and triangular, sawtooth and rectangular...

A high-frequency transistor of planar structure having emitter and base regions of extremely fine structure to reduce the junction capacity. For the wire bond connection between said emitter or base region and an external lead wire, the transistor has the aluminium electrodes which swell and extend on the insulating film.

A frequency divider which divides clock pulses to obtain the clock frequency of a desired dividing ratio comprises a binary counter, cycle data forming circuit and inhibit circuit to which the dividing ratio is fed in the form of the dividing ratio data. The counter counts the clock pulses, and the cycle data forming circuit converts the count value of the binary counter to a cycle data in which a certain single bit only becomes a logical state "1" and the rest of the bits are a state "0". The b...