Abstract: An electronic musical instrument is provided with a keyboard circuit, a voltage-controlled tone signal generating circuit arrangement and a sequencer for sequentially coupling memorized pitch voltage signals to the voltage-controlled tone signal generating circuit arrangement, thereby realizing automatic arpeggio performance. The sequencer is so connected as to receive a pitch determining voltage signal from the keyboard circuit at a given timing and is so arranged that the magnitudes of pitch voltage signals coupled to the tone signal generating circuit arrangement are shifted in accordance with the pitch determining voltage signal from the keyboard circuit, thus achieving transposition of arpeggio.

Abstract: An electronic musical instrument comprises first and second voltage-controlled frequency-variable oscillators responsive to application of a pitch determining voltage signal from a keyboard circuit to produce first and second audible frequency signals, respectively. The second audible frequency signal is coupled to the first voltage-controlled oscillator to produce a frequency-modulated tone signal to be sounded in which the first audible frequency signal is frequency-modulated with the second audible frequency signal. The content of harmonic components in a musical tone can be increased by sideband components resulting from frequency modulation. The second audible frequency signal may be amplitude-controlled to be proportional, in amplitude, to the magnitude of pitch determining voltage signal, amplitude-modulated with a time-varying control waveform, and/or waveform-modified to provide desirable modulation effects.

Abstract: An electronic musical instrument comprises a plurality of tone generators for independently producing tone signals having slightly different frequencies, though fundamentally corresponding to the note of a key depressed on a keyboard; and a mixing circuit coupled to the outputs of the tone generators. The respective tone generators are provided with a control input and are brought to start in the same phase in response to application of an initial synchronizing pulse to the control inputs, thereby attaining clear rise of musical sounds immediately upon key depression. The synchronizing pulse may be produced necessarily at the instant of key depression only when an output of the mixing circuit has a amplitude level lower than a predetermined level.

Abstract: In an electronic musical instrument a key touch signal is generated in response to the operation of a key, and a plurality of control signals having different waveforms are produced from the key touch signal.Different control signals are used for independently controlling at least two of a plurality of musical tone elements that determine the tone pitch, color and volume of the musical tone generated by the musical instrument.

Abstract: An electronic musical instrument capable of controlling tone pitch, tone color, volume etc. of a musical tone by a sliding operation to conduct such on effect as portamento. The instrument according to the invention can produce a control signal proportional to a sliding distance on a portamento playing actuator regardless of an initially touched position on the actuator. For producing such control signal, an output voltage from a portamento playing actuator corresponding to a finger touch position is applied to a positive input of a calculator whereas a voltage obtained by sampling and holding an output voltage corresponding to the initial touch position is applied to a negative input of the calculator. Difference between the two voltages is outputted as a control voltage from the calculator and this control voltage is utilized for controlling VCO, VCF or VCA thereby to control the tone pitch, tone color, volume etc. of a musical tone.

Abstract: This invention provides an electronic musical instrument comprising a keyboard circuit for producing a pitch determining voltage signal representing the note of an operated key, a voltage controlled oscillator for producing a tone signal having a tone pitch determined by the pitch determining voltage signal, and a voltage controlled lowpass filter for imparting a desired tone color to the tone signal. The voltage controlled lowpass filter is responsive to the pitch determining voltage signal from the keyboard circuit to control the cutoff frequency of the voltage controlled lowpass filter in such a manner that the harmonic content of a higher tone signal is decreased from that of a lower tone signal.

Abstract: An automatic rhythm performance system is provided with a rhythm pattern changing circuit comprising a white noise source and a sample hold circuit which samples the output of the white noise source in response to a pulse signal occurring at the beginning of every measure of a rhythm to produce a sustained voltage of a sampled value which will be different for every measure. The sample hold circuit voltage is applied to a rhythm selecting circuit to modify the preselected pattern of the rhythm.

Abstract: In an electronic musical instrument, an expression control circuit constituted by a first variable resistor is connected in the path of the tone signal. A second variable resistor is connected in series with or in parallel to the first. A third variable resistor is connected in shunt between the output side of the expression control circuit and the ground. The second and the third variable resistors can adjust the variation range of the tone signal at the output of the first variable resistance.

Abstract: This invention relates to a voltage controlled type electronic musical instrument comprising a keyboard section for generating a pitch determining voltage signal and a trigger signal upon key operation, a voltage controlled tone signal generating circuit including a voltage controlled oscillator, voltage controlled filter and voltage controlled amplifier for generating a tone signal in response to the pitch determining voltage signal and control wave generating circuits responsive to the trigger signal for generating control waves coupled to the voltage controlled oscillator, voltage controlled filter and voltage controlled amplifier. The pitch determining voltage signal is coupled to the voltage controlled amplifier so as to control the gain thereof, thereby decreasing the volume of musical sounds at higher frequency from that of musical sounds at lower frequency.

Abstract: 2,2'-Cyclocytidine is prepared by reacting cytidine with a functional derivative of silicon, and hydrolyzing the reaction product under acidic conditions. 1-.beta.-D-Arabinofuranosyl cytosine is prepared by reaction of cytidine with a functional derivative of silicon, followed by alkaline hydrolysis of the reaction product. 2,2'-Cyclocytidine and 1-.beta.-D-arabinofuranosyl cytosine are useful as antitumor and antiviral agents.