Abstract: In a waveshape memory, a first waveshape of plural periods including an attack portion and a second waveshape of plural periods are stored. A tone waveshape signal is produced by reading out the first waveshape once and thereafter reading out the second waveshape repeatedly. The first waveshape is a first section including an attack portion cut off from a desired original tone waveshape. The second waveshape is principally composed of a second specified section succeeding the first specified section cut off from the original tone waveshape. A terminal portion in the second specified section is weighted with decay characteristics and is added with a corresponding terminal portion of the first specified section which has been weighted with attack characteristics, thereby effecting smooth connection between the respective waveshapes.

Abstract: A keyboard operated electronic musical instrument is disclosed in which a first set of tone generators is assigned to actuated keyswitches on a first keyboard and a second set of tone generators is nominally assigned to actuated keyswitches on a second keyboard. Assignment logic is provided so that when all the members of the first set of tone generators have been assigned an addition keyswitch actuation causes the temporary borrowing of one of the tone generators in the second set to respond to the newly actuated keyswitch. Saturation of tone generator assignment is diminished by a glissando detect subsystem which inhibits the use of a long release envelope release phase if a glissando has been initiated.

Abstract: A touch sensitive system for an electronic musical instrument providing a multiple key switch contact system for effecting control over two or more tone generating systems. The first tone generating system operating rapidly in response to the actuation of the key switch to produce a desired voice. The second or subsequent tone generating systems operate sequentially in a delayed manner on the actuation of the key switch effecting a predetermined delay in the production of the desired voice. The audio output of each of the tone generating systems is summed forming a resultant waveform for audio amplification. The key switch actuation, depression and release, causes the tone generating systems to respond immediately to the depression or release of the key switch which effects a change in the envelope characteristics of the resultant waveform.

Abstract: The present invention provides a touch response apparatus for an electronic keyboard instrument wherein, in controlling a touch response state by detecting a key depression speed in the electronic keyboard instrument, the touch response states of keys are detected by detection means smaller in number than the keys, and the difference of detection outputs attributed to the different mounting positions of the contacts of a white key and a black key is also compensated.

Abstract: A method and apparatus for reproducing the complete attack transient and steady state portions of a waveform is disclosed.

Abstract: The invention relates to an electronic percussion-type musical instrument, such as an electronic piano, capable of producing electronically sounds simulating a piano, harpsichord or other keyboard percussion instrument. The keyboard is multiplexed to produce a serial time division multiplexed data stream having tri-level encoded signals in time slots corresponding to the keys, wherein the encoded signals indicate whether the key is undepressed, partially depressed or fully depressed. The amount of time for the key to travel in its undepressed to its fully depressed state is detected and a binary representation of the key velocity correlated to this timing is stored in a memory for readout synchronized with the scanning of the keyboard. In each time slot, a portion of the percussion envelope for the pertaining key is calculated and generated together with the discrete amplitude levels for the percussion envelope in a digital to analog conversion circuit.

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: An electro-acoustic transducer drive circuit for driving a device such as a miniature piezoelectric buzzer to emit musical notes, the notes having a damped waveform envelope whose shape is controlled by digital signals. The notes are formed by mutually independent circuit means and can be combined to produce musical chords. The circuit incorporates relatively few elements, and is suitable for implementation within a MOS IC.

Abstract: A tone source system for a superior electronic musical instrument suitable for an LSI application in which the wave data can be provided in a time division multiplex form, or the envelope data can be provided in a time division multiplex form in a synchronous relationship with it, and the wave data to which the envelopes are attached can be provided in a time division multiplex form through multiplication of the data.

Abstract: Disclosed is a musical envelope control device which is used in an electronic watch with a melody alarm function.

Abstract: Frequency data read out from a frequency data conversion ROM in response to a key code generated at a keyboard according to a depressed note key is accumulated at an accumulator and the accumulated result is supplied to an A input terminals of an adder. On the other hand, envelope data generated by an envelope data generating circuit is supplied to a B input terminal of the adder through exclusive OR gates under the control of a clock .0.. The frequency data and envelope data are summed at the adder and the resultant of addition is supplied as an addressing signal to a sine wave ROM for reading out therefrom an envelope-controlled musical sound signal.

Abstract: A method and apparatus for interpolating between the harmonic structures of a waveform stored in memory during portions or the entire transient periods of said waveform. In an electronic musical instrument having a greater number of selectively actuable switches than note generators to cause the production of sounds corresponding to the respective notes of a musical scale, the present invention interpolates between the harmonic structures of a waveform stored in memory during portions or the entire transient periods of said waveform. This is accomplished through the use of memory units having a number of locations or zones within each memory where the number of zones is equivalent to the number of discrete harmonic structures.

Abstract: This is an electronic organ which economically simulates long duration aperiodic musical waveforms, such as the clash of cymbals. It employs the digital waveform generation technique, in which successive instructions are read out of a memory to determine the amplitude of the waveform at successive sample points. To save memory capacity, the memory addresses are rescanned; and to avoid audible discontinuities the scan direction recirculates numerically back and forth across the address field. Despite the bidirectionality of the scan, monotonic decreases in amplitude and in higher harmonic content are achieved. The monotonic decrease in amplitude is accomplished by impressing an exponentially declining envelope upon the digitally generated amplitudes. The monotonic decrease in higher harmonic content is accomplished by preventing the rescan from returning to a memory region of greater harmonic content after it has once entered a region of lesser harmonic content.

Abstract: An envelope wave shape for each musical tone wave shape is generated per each key operation. The rate of change of the envelope wave shape to be generated are switched at timings corresponding to key operation speed of an operated key, thereby enabling an electronic musical instrument to generate musical tones of different envelope patterns depending on key operation speed just like on a pipe organ.

Abstract: An electronic musical instrument wherein purely digital techniques are utilized for generating the basic waveform train and also keying the waveform train so as to have the customary keying envelope with attack, sustain and decay portions. The wavetrain is a cyclically repeated series of four-term Blackman-Harris window functions, wherein there are preferably eight such functions in each series. A plurality of individual keying envelopes are generated by a piecewise linear technique, and these envelopes are assigned respectively to the waveforms in the series so that the relative amplitudes of the waveforms can change with time over the life of the tone. This results in modulating with time the harmonic content of the tone.

Abstract: A digital musical tone signal is generated in a first LSI selected by a chip select signal transferred from a CPU in accordance with a control signal transferred through a control bus from the CPU. Amplitude data and envelope data are transferred from a second LSI to the first LSI through data lines. In the first LSI, the digital musical tone signal amplitude- and envelope-controlled is transferred to an A/D converter where it is converted into an analog musical tone signal.

Abstract: Disclosed is a musical envelope-producing device which may be employed for an electronic watch with a melody performance function. The musical envelope-producing device has a memory which stores musical performance data representing pitches and durations of notes; an address counter; a pitch divider which generates a frequency signal corresponding to the pitch data; a note control circuit which divides a duration corresponding to the duration data into eight time components and generates a predetermined division signal when the duration has elapsed; and an envelope circuit which produces a sound pressure signal which is sequentially attenuated in a stepped manner in response to the division signal and which synthesizes the sound pressure signal and the frequency signal.

Abstract: A key-speed-responsive volume control apparatus for a keyboard-type electronic musical instrument includes a key switch associated with a key of the instrument, wherein a movable contact of the key switch moves out of engagement with a break contact and into engagement with a make contact upon depression of the key. A capacitor is charged following the movement of the movable contact out of engagement with the break contact and before engagement with the make contact. The capacitor is made to discharge at a first prescribed rate immediately after charging until the movable contact comes into engagement with the make contact, and then at a second prescribed rate until the movable contact disengages the make contact upon release of the key.

Abstract: Waveform data for converting attack, decay and release status sections of a musical sound envelope into an exponential function waveform is obtained from an envelope generator wherein exponential function waveform data is read out from a ROM or obtained through calculation based upon an exponential function in a digital logic processing circuit, and it is used for the envelope control of a tone signal from a digital wave generator.

Abstract: A percussion generator for an electronic musical instrument, such as an electronic organ, wherein the percussion generator is responsive to a time division multiplexed serial data stream produced by scanning the keys of the keyboard. A control pulse is produced each time that a new key on the keyboard is depressed, and this pulse, which has a duration equal to or greater than a plurality of scans of the keyboard, is employed to produce a burst of keydown pulses in the data stream. The percussion generator is responsive to the serial data stream and each of the aforementioned control pulses to produce keydown pulses in the appropriate time slots of the data stream in a plurality of successive sequences thereof and then terminate the keydown pulses even though the associated keys remain depressed.

Abstract: Envelope curves for a large number of individual sounds to be digitally synthesized are generated by storing sample envelope shapes. The duration of the stored curves is varied by exercising control over the sampling of the stored envelopes. The smooth transition from one envelope curve to another is accomplished by sampling the new curve at a fast rate until substantially matching values of the previous and new curve are found and then proceeding with the sampling of the new curve at the desired rate.

Abstract: In the generation of an envelope waveshape of a musical note to be produced in response to a key depression, speed parameters of the envelope which are determined corresponding to the speed of its attack, decay and release are produced digitally. The envelope waveshape is obtained by calculations based on the speed parameters. The formation of the envelope waveshape of the musical note, its volume level control and its tone control can be achieved with simple arrangements.

Abstract: The disclosed organ employs keyboard-activated transfer of individualized tone and envelope-generating information from large memories for each distinctive set of a note's harmonics, to small memories in small circuits corresponding to each harmonic set. Selection of large memories programmed for different temperaments or voice types renders the organ playable as one or another type of organ (e.g., gothic, classical, romantic, theater) in a variety of temperaments (e.g., just-temperament, mean-tone, equal-temperament). Information transferred from any selected large memory causes a circuit common to one or more sets of a note's harmonics to sweep the harmonic data transferred to the small memories for all the note's harmonic sets, to generate respective currents representing attack and decay envelopes for all the note's harmonic sets.

Abstract: The string snub effect functions so as to introduce a different set of parameters for the harmonic content, envelope amplitude, shape and rate of decay and pitch of the resulting sound upon key release when a percussive string-type voice is selected in an electronic musical instrument. The apparatus for causing a snubbing of the resulting tone comprises a means for selecting a percussive string-type waveform and for generating a signal indicative of such selection, a means for detecting the release of a depressed key and the presence of the signal indicative of the selection of a percussive string-type waveform and for generating a signal indicative of such detection, a means for halting further interpolation of the selected waveform and switching to a preselected harmonic structure of said selected waveform, means for shifting the pitch of the generated tone of said selected waveform, and means for variably controlling the envelope amplitude, shape and rate of decay of the selected waveform.

Abstract: An electrical sound output signal from an acoustical-electrical or piezo electric transducer instrument is made available at selectively switched high and low signal levels by level control apparatus utilizing bistable switching of first and second attenuated electrical sound output signals. A flip-flop circuit toggles between first and second states in response to an input signal pulse generated by actuation of a footswitch. Oppositely-phased output signals produced by the flip-flop are applied to first and second switching FETs controlled thereby so as to be alternately conducting. The FETs are connected between respective first and second attenuators providing high and low level-controlled sound output signals and common output terminals. Accordingly, upon selective actuation of the footswitch, either high or low level controlled sound output signals can be made available at the output terminals.

Abstract: A touch responsive envelope control system is provided for use in an electronic musical instrument having a multiplexed keyboard, a plurality of assignable tone generators, each being assignable to producing a single note of one or more notes corresponding to one or more actuated keys of the keyboard and a keyer associated with each tone generating means for keying the generated tone with controlled attack time and decay rate and a controllable peak amplitude. The touch responsive system comprises a peak amplitude control system responsive to the actuation of each key for keying the associated tone with a peak amplitude corresponding to the intensity of actuation thereof. The peak amplitude control system includes an encoding circuit responsive to the actuation of each actuated key for producing an encoded intensity signal corresponding to the intensity of actuation thereof and a decoding circuit responsive to each encoded intensity signal for producing a corresponding peak amplitude control signal.

Abstract: A musical door chime which includes a repertoire of musical tunes one of which is played when a door pushbutton, preferably the front door pushbutton, is actuated. The musical tune which is played may be selected by means of a keyboard connected to a microprocessor. Digitally encoded representations of the notes of each musical tune are stored in a memory. Each digitally encoded musical note is read from memory by the microprocessor and converted by the microprocessor into a squarewave having the frequency and the duration of the note. The microprocessor is connected to a note strike and decay circuit which is preferably connected in series with an active audio filter circuit for translating the squarewave into a sinusoidal output for energizing a loudspeaker so that relatively high quality audible tones are heard when the musical tune is played.

Abstract: A tone signal having been data compressed or expanded is obtained through a circuit for taking the sum of upper three bits of envelope data, a latch for storing the output of said circuit, a circuit for setting the extent of bit shift of digital tone data according to the output of said latch, a latch group for latching the tone data having been bit shifted according to the output of the setting circuit, and an amplifier, the amplification level of which is set according to the extent of bit shift and which receives and amplifies the bit shifted tone data from a digital-to-analog converter.

Abstract: In a electronic musical instrument wherein a portamento is played by supplying the pitch voltage corresponding to a subsequently depressed key to a capacitor holding the pitch voltage corresponding to a previously depressed key, the charge and discharge currents of the capacitor corresponding to the difference between the two pitch voltages are controlled to vary exponentially thus changing exponentially the capacitor terminal voltage. The terminal voltage of the capacitor is applied to drive a voltage controlled oscillator to vary its oscillation frequency. To vary exponentially the terminal voltage of the capacitor, a mutual conductance converter is connected between the capacitor and a keyboard section and the output current from the mutual conductance converter is controlled by a control signal corresponding to the terminal voltage of the capacitor.

Abstract: A multiplexed electronic organ utilizing a plurality of integrated circuit chips, each chip time division multiplexing selected keying envelope time constant signals from a switched capacitor time constant generator for two alphabetic notes over the entire frequency range of a spinet or for one alphabetic note over the entire frequency range of the manuals and pedals of a console organ. The same integrated circuit chip is used for both spinet or console organs. Each chip contains a multiplexer circuit which isolates the multiplexed keying envelope output signals from the time constant generator and includes as a coupling means a plurality of switching element arranged into groups. Some of the groups are interconnected to provide the keying envelope time constant signal normally intended for one frequency range to the output associated with a different frequency range.

Abstract: Circuit means for synthesizing the sound of a mechanical bell by combining the three most significant frequencies of the bell to be synthesized and modulating these with a decaying exponential control signal which is derived from a clock signal having a pulse repetition rate equal to the stroke repetition rate of the bell being synthesized. The combined and modulated signal is amplified and coupled to suitable audio distribution means. Modulation of the exponential signal can provide a tremolo effect.

Abstract: A circuit for producing musical tones is disclosed which includes a keyboard for selecting the musical tones, and a tone generator responsive to the keyboard for generating a square wave signal having the frequency of the musical note to be generated. A charging circuit is provided for charging a capacitor to a predetermined level of voltage when the square wave signal is terminated, and for exponentially discharging the capacitor when the square wave signal is initiated. A modulation circuit amplitude modulates the square wave signal in proportion to the capacitor voltage to produce an exponentially decaying signal which simulates the waveform produced by a struck piano string. A speaker is also included to convert the exponentially decaying signal into audible musical tones having the sound of piano notes. The circuit of the invention requires only a small number of components, making it suitable for use in miniature musical toys.

Abstract: The invention relates to a circuit for synthesizing either simple or complex waveforms of the type used in electronic musical instruments, such as electronic organs. In the specific embodiment disclosed herein, the synthesizing circuit is utilized in a rhythm unit for producing a damped sine wave charateristic of certain drum sounds. Opposite polarity waveforms are simultaneously produced by a switched capacitor technique driven by an attack/decay clocking signal and under the control of a keying signal received from a suitable low frequency rhythm clock source. The positive and negative waveforms are alternately selected in order to produce bipolar pulses at the frequency of the desired tone, and these pulses are connected to the input of a switched capacitor filter that modifies the pulses to produce a sine wave signal having an amplitude following that of the desired damped envelope.

Abstract: A plurality of sets of such characteristics as the color, volume and effect of a musical tone are preset for different musical composition fashions. Desired preset characteristics are selected independently in the melody performance portion and the accompaniment performance portion by operating a corresponding melody musical composition fashion selection switch and a corresponding accompaniment musical fashion selection switch thus establishing a musical tone having a desired musical composition fashion for each portion. According to a modified embodiment, when either one of the melody and accompaniment musical composition fashion selection switches is operated, both the musical composition fashions of the melody performance portion and the accompaniment portion are established in predetermined manner.

Abstract: An electronic musical instrument of a polyphonic type comprises, first tone generating means capable of producing, in a first musical tone property, a plurality of musical tones respectively corresponding to a plurality of depressed keys, and further comprises second tone generating means capable of producing, in a second musical tone property, a musical tone corresponding to a specific key selected from said depressed keys in accordance with a predetermined standard of selection. The first musical tone property is set to be suitable for ensemble performance, whereas the second musical tone property is set to be suitable for solo performance. Among the musical tones produced by the first tone generating means, the one corresponding to the specific key is made less prominent than the ones corresponding to the other depressed keys.

Abstract: In an electronic musical instrument of the waveshape memory type including at least one waveshape memory for storing and reproducing sample values of a musical sound wave to be generated, the waveshape memory stores the sample values of the complete waveshape of a musical tone with a shaped envelope.

Abstract: In a wave generator for an electronic musical instrument, a plurality of sampling values of a musical tone waveform having a given envelope are simultaneously carried out in a time division system according to the musical tone waveform calculation sequence which can be varied as required; more specifically, calculation for generating a musical tone waveform is carried out while advancing phase, the envelope given to the musical tone waveform is divided into plural segments whose time intervals can be changed as desired, and phase increment values are set for the segments thus obtained while increment values are set for the phase increment values, respectively, these values being accumulated to carry out the calculation of the musical tone waveform, whereby the musical tone waveform and its envelope are varied intricately to produce musical tones rich in natural feeling.

Abstract: An electronic timepiece has an alarm function using circuitry and an electroacoustic transducer to generate a selected melody. The frequencies of the generated tones lie close to those of the standard chromatic or diatonic scales, and are produced by dividing the frequency of a time-standard signal. A plurality of notes can be generated.

Abstract: An envelope generator for use in an electronic musical instrument, such as an electronic organ, employing a dual charge pump to form the attack and decay portions of the envelope. The envelope generator is adapted to be connected to the envelope control input of the keyer and the other input of the keyer is connected to a tone source. When the appropriate key of the keyboard is depressed, a source of input voltage is connected to the input of the envelope generator and a first charge pump incrementally transfers the input voltage to a capacitor over a first sequence of discrete time frames. The first charge pump circuit comprises a pair of electronic switches clocked 180.degree. out of phase and a capacitor connected between the juncture of the two switches and ground potential. The second mentioned capacitor is much larger than the first mentioned capacitor so that the charge transfer from one to the other takes place in a plurality of discrete steps.

Abstract: A converter includes a voltage selector which employs IGFETs as voltage switching elements, and a controller which controls the IGFETs. Each of the IGFETs in the voltage selector is made either the P-channel type or the N-channel type, depending upon a voltage level to be thereby switched and a level of a binary signal supplied from the controller. As a result, a voltage of comparatively great level can be switched by a binary signal of small level amplitude.

Abstract: An electronic piano includes a tone generator having a pulse generator and a discrete TOS circuit for each octave. The input of the first TOS circuit is connected with the pulse generator and the input of each next-following TOS circuit is connected with the input of the preceding TOS circuit by a divide-by-two divider circuit. The outputs of each TOS circuit are connected with discrete control circuits each having an analog switch for each output of the respective TOS circuit. First inputs of the analog switches receive envelope control voltage signals on depression of the respective piano keys while second inputs of the analog switches receive tone signals from the corresponding outputs of the respective TOS circuits. The outputs of the analog switches transmit tone signals, which are modulated as a function of the intensity the corresponding envelope control voltage signals, to a loudspeaker by way of either one of two main branches of the respective control circuits.

Abstract: A key switch information assignor having a data processor unit which produces keyboard and octave codes which serve to poll and interrogate a keyboard circuit. In response to the polling, the keyboard circuit produces key information representing the depression and release of keyboard switches in the keyboard circuit. This key information is compared by the data processor unit with previous key information to determine an event of key depression or release. In response thereto, a note code is determined combining the key information with the keyboard and octave codes. The key code is then sent to an assignment memory for further use. An envelope generator is provided which sends signals to the data processor unit to indicate the end of note sounding and thereby release of the key code from the assignment memory. Special arrangements are made for high speed release when a demand signal is generated in the case of all channels of the assignment memory being utilized.

Abstract: A method and apparatus for interpolating between the harmonic structures of a waveform stored in memory during the transient periods of said waveform. In an electronic musical instrument having a greater number of selectively actuable switches than generators to cause the production of sound corresponding to the respective notes of the musical scale the present invention interpolates between the harmonic structures of a waveform stored in memory during the transient period of that waveform. This is accomplished through the use of memory units having a number of locations or zones within each memory where the number of zones is equivalent to the number of discrete harmonic structures. The first of the memory units contains a discrete fixed harmonic structure in each of its zones, and a second of the memory units contains a difference value in each of its zones where the difference value is equal to the difference between the discrete fixed harmonic structure in adjacent zones of the first memory.

Abstract: The electronic musical instrument is provided with a tone production means having tone production channels less than the total number of keys, a performance mode change detecting means, and a means for controlling tone production assignment of the tone production channels.The tone production assignment is controlled by depressed keys to one of the detecting means to produce a tone from one of the channel groups grouped according to the output of the detecting means. The selected tone production channel corresponds to the key group which the depressed keys belong to.

Abstract: An electronic musical instrument of simple arrangement wherein a plurality of musical tones of different musical instrument types are preset; musical tones of a desired musical instrument type is first selected; musical tones belonging to the selected one of the plural musical instrument types are played by performance keys; the performance keys are concurrently used for selection of musical tones of the desired musical instrument type, and which comprises a changeover switch for determining the application of the performance keys for the original purpose or for selection of a desired musical instrument type, thereby eliminating the necessity of providing separate musical instrument type-selecting key or keys in addition to the performance keys.

Abstract: An electronic musical instrument of digital processing in which required musical waveshape data are calculated by a tone control device to obtain a complex musical waveshape and the complex musical waveshape is read out at a read frequency produced by a key closure to generate the selected musical note.

Abstract: A digital envelope generator implemented in the form of an off-the-shelve microcomputer is disclosed. Five envelopes are produced simultaneously in multiplexed form and are output via a digital-to-analog converter and multiplexer to corresponding voltage controlled amplifiers/filters. The outputs are scaled in amplitude in accordance with touch response signals derived from a keyboard and the envelope time constants are scaled in accordance with the pitch of the notes selected by the keyboard. The outputs are available without further modification for controlling the Q of the filters, or the gain of amplifiers, and are simultaneously available with the amplitude scaled in accordance with the pitch of selected notes for controlling the frequency response of the voltage controlled filters.

Abstract: An electric piano has a complete player actuated piano voice of which harmonics are basically controlled by a tuning fork that is struck by the piano key. The piano is also provided with an electronically generated voice of which harmonics are electronically generated. To better enable the two voices to be played simultaneously by striking a single piano key, the amplitude envelope of the electromechanically generated piano voice is imposed upon the electronically generated voice which is gated and amplitude modulated so as to be heard in precise synchronization with a piano note produced by the instrument player. Linearity of modulation is extended to low piano voice amplitudes by use of modulating and gating diodes in oppositely poled feedback paths of an operational amplifier.

Abstract: The system comprises a frequency number memory device for storing information regarding the frequencies of respective tones, a keyboard switch for reading out frequency number information corresponding thereto from the memory device, an address generator including an adder for adding a predetermined number of the frequency number information thereby producing an address signal consisting of plural bits, address composers for processing the bits of the address signal and thereby composing digital tone signals constituting a saw-tooth, square and triangular waveshape, and digital-analog converters for converting the digital tone signals into analog tone signals, which are thereafter used to synthesize waveshapes of any tone.

Abstract: A fully digitalized function-of-time generator suitable for use as a tone envelope generator in a digital electronic musical instrument, comprising: a clock pulse generator for generating a clock pulse at a selectable rate; a gate enabled at each arrival of the clock pulse; a single-stage binary shift register for successively shifting out its contents as a digital word representing the instantaneous values of a desired function of time synchronously with the clock pulse; a digital subtractor; a digital multiplier; and a digital adder, all of these members being interconnected to each other to be operative so that the output of the register is subtracted from a first set value representing a digital word, the resulting difference being multiplied by a second set value representing a digital word, the resulting product being added to the output of the register via the gate, so that the resulting sum is loaded into the register.