Abstract: A tone signal applied from outside is sampled by a tone sampling device and the sampled waveshape data is written into a memory. During this writing operation and in parallel with the writing operation, a zero crossing point of the waveshape in terms of the sample data of the tone signal is detected. A final address detection circuit stores, each time a zero cross has been detected, a write address of the waveshape sample data with respect to the memory. Address data which is stored in the final address detection circuit when the writing of the waveshape sample data in the memory has been completed is detected as a final address of the sampled waveshape data. The waveshape data in the memory is read out either in a forward direction in a reverse direction using this final address as a start point or an end point and a tone signal corresponding to the sampled waveshape data is sounded. Such address constituting the start point or end point of reading, i.e.

Abstract: A tone generator includes a plurality of tone generation channels each comprising one or more operation channels. One operation channel performs basic operation of a tone signal computing operation (e.g., FM or AM) and a tone signal is generated by using one or more operation channels for one tone generation channel. Tone generation channels in the tone generator are established according to a selected performance mode. In a first mode, the operation channels are divided into N groups and N tone generation channels are established in correspondence to the respective operation channel groups. In a second mode, the operation channels are divided into M groups and M tone generation channels are established in correspondence to the respective operation channel groups wherein N is a different number from M. Tone generation channels of the number required according to the selected performance mode can be established by efficiently utilizing the operation channels of a limited number.

Abstract: A sequential-access memory of an auto-refreshing type has an increased storage capacity. The sequential-access memory has at least two dynamic-type memory cell arrays serially connected to one another to form a loop. Each array comprises N rows by M columns of memory cells each having a read selection line and a write selection line. The read selection line of each memory cell of each row is connected to the write selection line of the memory cell of the same row which comes next to the each memory cell to form an address selection line. The address selection lines of each memory cell array are activated one after another to effect a sequential access to the memory cell array. Data read form each memory cell array is fed through a delay circuit to the memory cell array which comes next to the each memory cell array. A logic circuit for subjecting data outputted from one memory array may be additionally provided to feed data representative of the result of the predetermined operation to the next memory array.

Abstract: An electronic musical instrument is provided of the type in which a musical tone signal is formed by executing computations according to a mathematical formula such as a frequency modulation formula. Tone formation of each of musical tone signals to be simultaneously formed is assigned to each time-division-multiplexed time channel which is cyclically repeated over cycles of a plurality of time slots. A computation for forming each single musical tone is divided into a plurality of sub-computations, and those sub-computations are executed respectively using a plurality of cycles of time slots of each single time channel. Thus tone formation according to a complex computation formula is realized. Parameters necessary for the computation are generated respectively for each time slot so that any computational formula is adopted as desired by selecting predetermined parameters for each time slot.

Abstract: An electronic musical instrument is provided of the type in which a musical tone signal is formed by executing computations according to a mathematical formula such as a frequency modulation formula. Tone formation of each of musical tone signals to be simultaneously formed is assigned to each time-division-multiplexed time channel which is cyclically repeated over cycles of a plurality of time slots. A computation for forming each single musical tone is divided into a plurality of sub-computations, and those subcomputations are executed respectively using a plurality of cycles of time slots of each single time channel. Thus tone formation according to a complex computation formula is realized. Parameters necessary for the computation are generated respectively for each time slot so that any computational formula is adopted as desired by selecting predetermined parameters for each time slot.

Abstract: An electronic musical instrument comprises means for detecting depressed-keys on a keyboard to generate key informations corresponding to said depressed keys, and means for generating a musical tone signal which varies pitch from the pitch of a musical tone generated by a firstly-depressed key to the pitch of a musical tone generated by a secondly-depressed key, in accordance with a key information of said firstly-depressed key and a key information of said secondly-depressed key. In the instrument, means is provided for generating an amplitude coefficient which sequentialy varies from an amplitude of the musical tone generated by the firstly-depressed key to an amplitude of the musical tone generated by the secondly-depressed key whereby the amplitude of said musical tone signal is controlled according to said amplitude coefficient.

Abstract: An electronic musical instrument includes an upper, lower and pedal key boards and a solo keyboard, key switches and associated circuits for producing key codes of the depressed keys, and musical tone signal generators which generate musical tone signals in accordnace with the key codes. A priority selection circuit is provided for selecting a single key code from among a plurality of concurrent key codes with respect to plural keyboards in accordance with a predetermined order of priority, and a musical signal is generated by a predetermined generating system for producing a musical tone signal generator in accordance with the selected key code. Thus, a special intermanual coupler effect is realized.

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 having a plurality of keys is provided with a depressed key detector which detects depressed keys and produces key identifying signals; a highest signal detector which detects a highest one among the key identifying signals having a highest priority in accordance with a predetermined order of priority; a musical tone producing unit responsive to the detected highest signal for producing a musical tone of a tone pitch corresponding to the highest signal; a reference memory device for storing the detected highest signal in accordance with a predetermined condition; and a controller for inhibiting the musical tone producing unit from producing the musical tone according to a relationship between the detected highest signal and an output of the reference memory device.Thus the progression of simultaneous plural key depressions provides a melody performance including rests.

Abstract: An electronic musical instrument is of a key assigner type including a key coder and a channel processor, and is equipped with an automatic bass/chord performance faculty. The key coder includes a root note memory and a chord type memory, whereas the channel processor includes a key code memory and a key-on memory. The instrument is provided with a chord note memory function rendering switch and a bass note memory function rendering switch. When the chord note memory function rendering switch is turned on, the key-on memory is not cleared after release of the keys for conducting a automatic performance of chord tones. When the bass note memory function rendering switch is turned on, the root note memory and the chord type memory are not cleared after release of the keys for conducting an automatic performance of bass tones.Thus a bass-note memorized automatic accompaniment performance and a chord-note memorized automatic accompaniment performance are independently selectable.

Abstract: In a control waveform generator for an electronic musical instrument of the type wherein the generator generates a control waveform adapted to control at least one of a tone pitch, a tone color and a tone volume, the control waveform generator is constituted by a pulse generator for generating a pulse signal having a repetitive frequency, and a detector including a counter which starts to count the number of the pulse signals when a key is depressed. The detector generates a first detection signal during an interval between depression of the key and a time at which a counter reaches a predetermined value and then produces a second detection signal until the depressed key is released.

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: An automatic accompaniment apparatus capable of automatically producing a bass tone by developing notes constituting a chord in the form of a broken chord in a predetermined order when keys constituting such chord are depressed. When a plurality of keys are depressed, there often exist a plurality of different chords constituted of notes corresponding to the depressed keys. The automatic accompaniment apparatus according to the invention is adapted to detect a single chord name among these plural chords in a certain predetermined order of preference and use the fundamental note and other notes constituting the detected chord as the bass accompaniment tone. The apparatus is capable of selectively restricting generation of notes other than the fundamental note which would normally be generated in the bass accompaniment using a predetermined note as the fundamental note, thereby providing bass variation effects to the generated bass tone.

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 monophonic electronic musical instrument comprises a single key preferential selection device. Key switches are connected in a matrix fashion between the group lines and the individual lines. The group lines are sequentially and repetitively scanned to detect the first one in the sequence of the groups where any key switch is closed, and the individual lines to which any closed key is connected deliver key detection signals, which in turn are introduced into a preference circuit to select the key detection signal of the highest priority. The group detection and the individual detection co-operatively designate a single key for tone production.

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.