Abstract: A percussion processor for an electronic musical instrument, such as an electronic organ in which information representative of the actuation of selected switches corresponding to associated notes of the musical scale is furnished in the form of a time-division multiplexed signal having repetitive sequences of time slots, includes a delay circuit comprising a shift register having a time delay period equal to the duration of one of the sequences of time slots or an integer multiple thereof. The multiplexed signal train is applied to the delay circuit and also is applied in parallel to an inverter circuit. The output of the inverter and the output of the shift register are connected to different inputs of a NAND gate.

Abstract: 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.

Abstract: The invention relates to an apparatus for producing a vibrato effect in acoustic signals, particularly for electronic organs, in which the output signals are obtained by successively scanning a plurality of points of a delay line fed by the acoustic signals.

Abstract: A reverberation device is provided with a delay line in series with an amplifier which is designed to compensate for the inherent frequency dependent attenuation of the delay line. The output of the compensating amplifier is fed back directly to the delay line input.

Abstract: The invention provides a circuit for an all-pass reverberator with an MOS delay line and feed back amplifier. The circuit compensates for the frequency-dependent attenuation of the delay line. Two amplifiers of the prior art circuit are replaced by resistors and a third one has specific characteristics.