Abstract: A motif performing apparatus for use in an electronic musical instrument, which effects an automatic performance of a motif only while sounds are being radiated. The motif performing apparatus is able to store information representing motifs to be played, and to read and output information representing each of the motifs, separately, while instruction units for instructing a radiation of musical sounds are operated. Accordingly, even if the operation of an instruction unit is unchanged, the performance is varied according to a pattern of the information. Further, as long as the instruction unit is operated, a plurality of musical sounds are generated automatically and sequentially according to the pattern of the information, and thus a performance can be easily effected.

Abstract: Frequency information is stored in a tone coefficient memory and accumulated to obtain address information for reading out a musical sound from a musical waveshape memory by a musical sound generating circuit. Envelope information is stored in an envelope coefficient memory and accumulated to obtain address information for reading out an envelope waveshape from an envelope memory by an envelope generating circuit. An address counter performs address assignment for operating the musical sound generating circuit and the envelope generating circuit on a time-divided basis. The frequency information and the envelope information are respectively accumulated by a common accumulator on the time-divided basis. Further, attack and decay coefficients are stored in the envelope memory by higher and lower order bits of the same address, respectively, and the contents of the higher and lower order bits are selectively read out.

Abstract: A rhythm tone source which is provided with a noise generator composed of a plurality of shift registers which generate random pulses in synchronism with clock pulses supplied thereto, respectively, means for selecting the clock pulses to be applied to the shift registers, and means for controlling the input and output connections between the shift registers. The both means are changed over in combination with each other.

Abstract: An electronic musical instrument in which rhythms are each subjected to digital processing and provided uniformly with out variations in volume and tone quality and respective envelope waveshapes are given different periods of attack and decay which are obtained with the same system by calculating attack and decay coefficient for the respective rhythms on a time divided bases.

Abstract: A tone source circuit for electronic musical instruments which enables the selection of a desired one of a plurality of waveshapes of different duty ratios and is suitable for fabrication as an integrated circuit. The tone source circuit is composed of a tone signal generator for producing a tone signal of a frequency corresponding to each tone, a frequency divider group for frequency dividing the tone signal to a plurality of stages in a sequential order, a waveshape forming circuit for obtaining a plurality of waveshapes of different duty ratios from output signals of the frequency dividing stages of the frequency divider group and/or a feet select circuit for selecting a plurality of combinations of frequency dividing stages of the frequency divider group, waveshape select means for selecting a desired waveshape from the plurality of waveshapes of different duty ratios and means for selectively deriving a signal of the selected waveshape in response to key depression.

Abstract: A noise generator in which a random pulse output is produced by a random pulse generator in synchronism with a predetermined clock and is stored in a latch circuit by a clock obtained by frequency dividing the predetermined clock to produce random pulses of a harmonic composition different from the abovesaid random pulse output, thus providing noises of two or more desired harmonic compositions from the random pulse generator.

Abstract: A rhythm generator which is provided with a plurality of rhythm pattern memories, each storing one rhythm pattern and outputting the rhythm pattern in response to a rhythm clock, a bar counter for counting the number of bars with the rhythm clock, and means supplied with the output from the bar counter to selectively assign desired ones of the rhythm pattern memories one after another for a desired number of bars.

Abstract: An automatic musical performance instrument which has a counter for counting a high-speed clock from a high-speed clock generator, a depressed key switch detector for generating a scanning pulse in synchronism with the high-speed clock to detect a depressed key switch, a circuit for storing in the form of a binary coded signal the output from the counter corresponding to the depressed key switch, a tone signal converter for converting the stored binary coded signal to a tone signal, and control means for sounding the tone signal in accordance with a rhythm pulse.

Abstract: A rhythm pattern variation device which has an address counter for generating a memory read-out address signal in accordance with a rhythm clock, a memory for outputting a prestored rhythm pattern in accordance with the address signal, means for selectively branching the outputted rhythm pattern to two lines, a variation circuit for producing a rhythm pattern of a desired time lag from the rhythm pattern on one of the two line, and means for combining the rhythm pattern on the other line and the delayed rhythm pattern from the variation circuit into a composition rhythm.