Takatoshi Okumura

Electronic musical instrument with automatic arpeggio performance device

An electronic musical instrument having a channel processor. The channel processor includes a tone production assignment circuit and an automatic arpeggio circuit. The tone production assignment circuit includes a key code memory circuit of a plurality of channels and an assignment control unit. A specific channel among the channels is used exclusively for the automatic arpeggio performance while the other channels are used for ordinary respective tone production corresponding to depressed keys by an ordinary key assignment operation responsive to depression of the keys. The automatic arpeggio circuit produces key codes one after another for the automatic arpeggio channel in accordance with the key codes already assigned to the respective ordinary channels and with arpeggio constituent orders in a sounding pattern. The arpeggio sounding pattern which is selected in response to a rhythm to be played contains binary data representing the arpeggio constituent orders. The arpeggio constituent orders herein mean the orders of the locations of the notes constituting the arpeggio alignment, the order being counted from the lowest one of the depressed keys in a predetermined keyboard range.

Musical tone waveshape generator

The invention is directed to a waveshape generator capable of producing a desired waveshape by previously storing basic amplitudes obtained by sampling one period of the waveshape at a coarse interval and calculating amplitudes with a fine interval between the basic amplitudes. While basic amplitudes A and B are sequentially produced at a coarse interval in response to an integer portion of the input data, a function X (c) is produced in response to a fraction portion of the input data. Waveshape amplitudes are interpolated between the basic amplitudes by carrying out calculation of A + (B - A) × X(c) in response to these values A, B and X(c). A special form of function X(c) is also used for applying interpolation by a partial waveshape of a trigonometric function wave. An example of a musical tone waveshape generator is also described in which different waveshapes are produced depending upon different tone ranges by moving the position of a radix point for each of the different tone ranges.

Electronic musical instrument with glide

In a digital type electronic musical instrument, a glide effect is produced by digitally frequency-modulating the frequency of a musical tone in such a manner that the frequency changes quickly and smoothly. Glide information used for effecting this frequency-modulation is produced on the basis of a glide code obtained by counting a clock pulse. The glide information which changes its contents uniformly is multiplied with the basic frequency information to effect the frequency-modulation. The glide effect can be controlled for each individual keyboard. According to an embodiment of the invention, the frequency-modulation is applied to an attack portion of a musical tone only and sustain and decay portions of the musical tone are reproduced with a normal frequency so that the musical tone will be provided with a crisp, vivid musical effect.

Electronic musical instrument having memories containing waveshapes of different type

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 waves are controlled in their relative levels in accordance with the tone-color of an intended musical tone wave shape. The sinusoidal waves and the triangular, sawtooth and rectangular waves are thereafter synthesized to produce a desired tone-color wave shape. Since the triangular, sawtooth and rectangular waves contain abundant harmonic components, many kinds of musical tones containing abundant harmonic components can be produced despite a limited number of waveform memories.

WAVEFORM PRODUCING SYSTEM

In a waveform producing system for use in, for example, an electronic musical instrument, a tone generator circuit and/or a tone control circuit including tone keyer circuits, each or either one of said tone generator circuit and said tone control circuit comprises: pulse generators associated with key-actuated switches, respectively; waveform memorizing means having at least one row of voltage dividers of which the division ratios are preset in characteristics corresponding to either the tone waveforms, the tone envelopes or the depression speeds of the key operated by the player of the instrument; sequential memory read-out means connected to the respective voltage dividers; and pulse generators thereby providing an enabling signal sequentially to the individual dividers every time a pulse is inputted from the pulse generators to read-out the memorized waveform in the form of a modified audio signal at the output side of the circuit. The memorized waveforms can arbitrarily be sampled (scanned) out by using a sampling circuit in the read-out means, thereby providing variations in the modified audio signal. The tone control circuit enables the tone level control in conformity to the depression speed of the key and tone envelope control without the need to employ the conventional charge-discharge circuit requiring a relatively large capacitance capacitor, and makes it easy to carry out circuit integration.

Tone wave generator in electronic musical instrument

In an electronic musical instrument, the keys of a keyboard are divided into a plurality of groups by octaves, and a wave generator is provided with a memory for storing constants corresponding to musical tone frequencies to be generated according to the notes includes in a desired group out of the plurality of group, an accumulator for repeatedly adding the constants read out of the memory, and a bit position shifting circuit for shifting the bit position of the data produced by the accumulator according to the octave range of a note to be produced, thereby to obtain the data varying repeatedly according to the frequency of a note to be produced, and to reduce the storing capacity of the memory when compared to the number of keys.

Electronic musical instrument of time‐shared digital processing type

An electronic musical instrument is of a time-shared digital processing type and capable of producing musical tones for a special performance. There are provided, at suitable time intervals, time periods in which no key code of a depressed key is produced by a key coder. During these time periods, a signal designating a special performance is generated. In a channel assignment circuit which assigns key codes of depressed keys to plural tone production channels there is provided a channel for an exclusive use for the special performance. A circuit for assigning data for the special performance transmits the data to the channel assignment circuit in response to the special performance designation signal from the key coder so that the data selected from among the key data already assigned to the tone production channels for ordinary performance are sequentially assigned to the channel allotted exclusively for the special performance. As an example of the special performance, description is made with respect to an automatic arpeggio performance in which tones are produced at designated orders of location from the lowest tone among the tones of the depressed keys.