A method and means for modulating the frequency of an analog signal to achieve a vibrato effect wherein the analog signal is transmitted through an analog shift register or delay line under the control of a digital clock signal and wherein the frequency of the digital clock signal is varied at a rate equal to the desired rate of modulation of the analog signal. In this manner, the output of the shift register is a delayed version of the input thereto, with the frequency modulated at the same rate that the clock signal frequency is modulated. According to the preferred embodiment of the invention, first and second shift registers are utilized and the analog signal is divided into upper and lower frequency bands which are separately applied to the two shift registers. Furthermore the shift register which receives the lower frequency band is clocked at one-half the rate of the shift register which receives the higher frequency band.

Electronic vibrato system

A plurality of a signal peak detection circuits connected in cascade for operation on a complex waveform input signal, for generating a reference signal having peaks occurring in time with the peaks of the fundamental frequency component of the input signal. The reference signal is processed for producing a voltage proportional to the period between successive signal peaks, which voltage is successively stored and monitored at select times for comparison of the relative magnitude changes in the voltage, for updating an output control voltage.

Frequency following circuit

In this electronic musical instrument a musical tone is generated by repetitively reading out a waveshape stored in a memory. Repetitive sets of phase information are produced, such phase information thus being a linear saw-tooth-like digital signal having a repetition period corresponding to the frequency of the generated musical tone. Phase distorting means modifies the shape of the phase information so as to distort said linear saw-tooth-like signal, without changing the repetition period thereof. The resultant altered phase information is used to access said memory so that during the supply of each of said repetitive sets, successive samples in different portions of said stored waveshape respectively are read out at different effective rates. Thus the waveshape samples read out from said memory will consitiute a musical tone having changed tone color but unchanged pitch.

Electronic musical instrument including waveshape memory and modifiable address control

There is provided a compact, low-cost decorative light blinking device which is capable of accurately and precisely blinking illuminants of channels in response to music (the frequency of sound), and which has circuitry with reduced number of components. An audio frequency range (from 20 Hz to 20 KHz) can be divided into about 10 frequencies. The decorative light blinking device flashing to music, includes a plurality of channels, each including a buffer amplifier, a PLL circuit connected to the buffer amplifier and having a phase comparator, a loop filter and voltage control oscillator and lock state detecting circuit which generates a positive or negative logic digital output signal, a time constant circuit connected to the PLL circuit, an output circuit connected to the time constant circuit, and a decorative illuminant connected to the output circuit and turned on or off by an output from the output circuit,and a signal input point into which input terminals of the buffer amplifiers of the channels are formed, and through which an electric music signal is input from audio equipment, free-running frequencies and capture ranges of the PLL circuits of the channels being arbitrarily set to within an audio frequency range so that the free-running frequencies and the capture ranges do not basically overlap with each other, the PLL circuits being set so as to be locked with respect to only frequencies corresponding to the capture ranges which are arbitrarily set in all frequency components constituting the music signal, whereby the time constant circuits integrate an output signal from the lock state detecting circuits in the PLL circuits to convert the decorative illuminants from a state where the decorative illuminants are always turned off to a state where the same are turned on.

Decorative light blinking device using PLL circuitry for blinking to music

An apparatus for forming a musical-tone waveform for an electronic musical instrument characterized in that at least one cycle of a musical-tone waveform, which it is desired be produced, is divided in amplitude by dividing lines at equal intervals and sampling points on a time axis are determined from respective crossing points between the waveform and the dividing lines and the distance between the initial and the final sampling points is represented by an appropriate number of pulses so that each sampling point may be represented by a pulse number. There is further provided a memory circuit wherein each sampling point, that is, the pulse number thereof is set up in the form of a digital signal. Additionally, there is a set up in the form of a digital signal a tendency such as increase, decrease or equal at each sampling point with reference to the preceding sampling point. An envelope setting device is used wherein the envelope of a muscial-tone waveform, which it is desired be produced, is subjected to sampling and the analog amount of each sampling point is set up in the form of digital signal. An accumulatively adding device is employed whereby the output digital signal of the envelope setting device is accumulatively added to or subtracted from the output digital signal of the memory circuit. The accumulatively adding device is connected at its output terminal to a D-A converter for converting its output signal into an analog signal.

Musical-tone-waveform forming apparatus for an electronic musical instrument

A sampling modulation system for an electronic musical instrument has an audio frequency signal source, a sampling circuit, a memory circuit for memorizing the sampled signals, an output circuit for reading out the signals from the memory circuit, a control circuit which generates a sampling pulse train and a reading pulse train, and a modulating signal source. At least either the sampling pulse train or the reading pulse train has the frequency modulated by the modulating signal generated from the modulating signal source so as to provide a periodical difference between the sampling frequency and the reading frequency and accordingly to produce a phase modulation.

Kawamoto Kinji

Papers

Sampling modulation system for an electronic musical instrument

Abtastmodulationssystem fuer ein elektronisches musikinstrument