Abstract: 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 bit which becomes "1" in the cycle data is uniquely determined by the count value. Further, each bit of the cycle data becomes "1" in proportion to the weight of the each bit. With the cycle data being thus formed, the dividing ratio data is simplified.The inhibit circuit receives the cycle data and the dividing ratio data to suspend the counting operation of the binary count if the bit of the dividing ratio data corresponding to the bit of the cycle data whose state is "1" is also "1".

Abstract: 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 memory device, and an arithmetic operating circuit is provided which selects ones from among the plurality of musical tone waveforms and mixes the selected ones of a mixing ratio, thereby forming a new musical tone waveform. The selected ones and the mixing ratio are predetermined corresponding to each of the tone ranges. Different tone colors of a number which is more than the number of the waveforms are realized for the respective tone ranges just like in a natural musical instrument.

Abstract: 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 discharge at a first prescribed rate immediately after charging until the movable contact comes into engagement with the make contact, and then at a second prescribed rate until the movable contact disengages the make contact upon release of the key.

Abstract: 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 read out the waveform in different rates in a time division multiplexed manner for different tones, and musical tone forming circuits for forming musical tones in accordance with the time division multiplexed waveform outputs of the waveform memory device.

Abstract: A digital oscillator generates a basic pulse having a period which is a predetermined large number of times of a clock pulse period. During the basic pulse period are allotted a predetermined small number of time slots defining submultiple frequency channels. There is provided a shift register having the channel number of stages, each stage being assigned to each channel. The contents of the respective stages are changed at respectively different periods which are multiples of the basic pulse period. The contents are taken out timewise-serially, one at a time, stage by stage, and superimposed on the basic pulse to constitute a time-division-multiplexed wave data signal. The delivered signal is demultiplexed to form individual waves having respectively different frequencies which are submultiple-related to the frequency of the basic pulse. This generator is very suitable for electronic musical instruments, as a single line transmits plural wave data.

Abstract: 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 data signal is converted by a shift register to parallel wave data signals, which are latched by a latch circuit. Selection of the octave is made by the latching time of the latch circuit determining the positions of the bits in the shift register to be latched. Rewriting of latched data in the latch circuit is effected each time the value of the data signal having the highest frequency among the wave data signals varies.

Abstract: An electronic musical instrument comprises a key on-off memory for storing the on-off state of the respective keys, and at a time counter for counting the lapse of time after release of the respective keys. The time counter inhibits generation of the musical tone signal corresponding to the key when the conditions that predetermined time is elapsed after the key release and that the key-off state is stored in the memory are satisfied. This inhibition is separately conducted with respect to the keys. Thus, it can remarkably prevent noise when the tone should not be produced.

Abstract: 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.

Abstract: Key switches are connected in a matrix fashion between row lines making block lines for octaves and column lines making note lines for notes. The note lines are connected to a note detection circuit which converts the note line outputs of the actuated switches into key codes in a time shared fashion and to a chord detection circuit which includes a chord type detecting logic and a shift register connected thereto and storing the note line outputs in its respective stages. During a chord detecting period, the note detection circuit is loaded with signals "1" as if all the key switches were actuated and delivers key codes of all notes one after another, whereas the shift register is circulatingly shifted synchronously with the note code change. When the logic detects an establishment of a chord, the note code of that moment is extracted to be a code identifying the root note of the chord. The root note code is then processed for automatic bass and chord performance.

Abstract: A digital oscillator generates a basic pulse having a period which is a predetermined large number of times of a clock pulse period. During the basic pulse period are allotted a predetermined small number of time slots defining submultiple frequency channels. There is provided a shift register having the channel number of stages, each stage being assigned to each channel. The contents of the respective stages are changed at respectively different periods which are multiples of the basic pulse period. The contents are taken out timewise-serially, one at a time, stage by stage, and superimposed on the basic pulse to constitute a time-division-multiplexed wave data signal. The delivered signal is demultiplexed to form individual waves having respectively different frequencies which are submultiple-related to the frequency of the basic pulse. This generator is very suitable for electronic musical instruments, as a single line transmits plural wave data.

Abstract: An electronic musical instrument is provided with an upper, a lower and a pedal keyboards and musical tone generating circuits dependently corresponding to respective keyboards and, in addition thereto, an auxiliary musical tone generating circuit which is independent of the keyboards and can be selectively coupled with a particular keyboard according to the designation by a keyboard selection switch. This auxiliary musical tone generating circuit produces tone signals having a particular tone color. Key codes for a selected one of the keyboards among key codes supplied by a channel assignment circuit are latched separately in the auxiliary circuit, and musical tones corresponding to the latched key codes are produced in this particular tone color.

Abstract: An electronic musical instrument of a key code processing type includes a single tone generating section for producing a solo performance effect without providing a solo performance keyboard. This single tone generating section comprises a single data selection circuit which selects the highest (or lowest) note from among notes of depressed keys for producing a single musical tone. The single data selection circuit includes first and second memories and a comparison circuit. An input key code A is compared with a key code X stored in the second memory and the input key code A is stored in the first memory if the value of the input key code A is greater than the value of the key code X. When one cycle of the above described comparison has been completed, the data stored in the second memory is rewritten with the data of the first memory. The key code for the highest note is now stored in the second memory to designate a tone signal to be produced for a solo performance.

Abstract: 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.

Abstract: A tone production assignment circuit produces control information representing assigned key code, key-on etc. Such information has a large number of bits with respect to each channel. A multiplexing circuit has output lines the number of which is smaller than the bit number of the information and divides the information with a plurality of time slots with respect to one channel. The multiplexing circuit is controlled by a signal from a timing signal generation circuit. The multiplexing circuit is capable of rearranging information for transmitting information required for the respective individual channels and also capable of inserting a timing data in an available time slot. A multiple data analysis circuit decodes the information provided by the multiplexing circuit. Tone generators are provided for the respective channels and each one of them functions to latch only corresponding information among the decoded information by a latch circuit.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A tone production assignment circuit produces control information representing assigned key code, key-on etc. Such information has a large number of bits with respect to each channel. A multiplexing circuit has output lines the number of which is smaller than the bit number of the information and divides the information with a plurality of time slots with respect to one channel. The multiplexing circuit is controlled by a signal from a timing signal generation circuit. The multiplexing circuit is capable of rearranging information for transmitting information required for the respective individual channels and also capable of inserting a timing data in an available time slot. A multiple data analysis circuit decodes the information provided by the multiplexing circuit. Tone generators are provided for the respective channels and each one of them functions to latch only corresponding information among the decoded information by a latch circuit.