Abstract: An electronic musical instrument having a waveform memory of a relatively small capacity for storing waveform information similar to conventional waveform information, the waveform memory being compatible with any data reading scheme. The waveform information is stored in the form of a plurality of frames. Each frame includes a plurality of pieces of sampled waveform data compressed by ADPCM or the like and decode information for extending the sampled waveform data to be read next to the current frame. Storing the decode information in a frame for extending the sampled waveform data stored in frames before and after that frame makes it possible to extract the necessary decode information from the frame read immediately before regardless of whether the frames are read forward or backward.

Abstract: An input data processor selects a value indicated by change border data, and uses this value as a reference value for determining whether a predetermined process is effected, and to change the currently used value indicated by the change border data to another value when the value of the input data becomes equal to a predetermined value. Namely, when the value of the input data is in the vicinity of a specific value, the detection of a change of the input data can be effected by using a resolution smaller than another resolution used for the detection when the value of the input data is not in the vicinity of the specific value. Detection of a change of the input data can be efficiently performed.

Abstract: An electronic musical instrument such as a synthesizer includes a preset memory for storing, as preset data, a plurality of sets of parameters such as tone colors, tone volumes, pitches, special effects, and the like of tones to be generated. A designated parameter value in the preset data is increased/decreased to edit the preset data. When an edit mode is released, the edited preset data is automatically saved in a recall data memory. When a "comparison" state is set during an edit operation, the preset data which is being edited is saved in the recall data memory, and preset data before editing or another preset data is set as tone generation data. When a "recall" operation is performed, data in the recall data memory is read out as the latest preset data for tone generation. The edit operation is performed while confirming generated tones by alternately executing the "comparison" and "recall" operations.

Abstract: A parameter signal generator including a parameter generating information storing unit for storing parameter generating information necessary for generating a parameter signal, and a parameter signal generating unit for generating a parameter signal. The parameter generating information is serially read from the parameter generating information storing unit and the thus-read parameter generating information is preset in a parameter signal generating unit other than the parameter generating information storing unit. Therefore, the parameter signal generator includes a storing unit other than the parameter signal generating unit, and accordingly, a general-use memory can be employed as the storing unit, to substantially lower cost. The processing of generating and radiating musical sounds can be performed at a practically required speed by employing a high speed processor as a central processing unit.

Abstract: A device for changing and controlling the rate of generating waveform data wherein rate changing data such as phase angle step data corresponding to steps, wherein each pair of contiguous steps has an interval smaller than a preset interval, are necessary. The necessary rate changing data of interval other than the preset rate changing data is obtained by effecting an interpolation from the preset rate changing data. Accordingly, it becomes unnecessary to store the rate changing data obtained by performing the interpolation, and thus, the quantity of the phase angle step data SD to the stored can be greatly reduced.

Abstract: An envelope generator for use in an electronic musical instrument comprises a musical tone data processing unit to evaluate a rate of change in a current value of musical tone envelope data with respect to a target value based on a parameter, a changing rate control unit for decrementing a change in the current value such that the current value becomes closer to the target value, a detection unit to detect whether or not the rate of change becomes equal to 0, and a processing control unit control for stopping the evaluation the current value in response to a result of the detection.

Abstract: An electronic musical instrument includes a decimal point position converting device for dividing an address corresponding to key information into an integer portion address and a decimal point portion address, the integer portion address being readout and sent to a waveform data memory as a read address, wherein a bit number of the address for access to the waveform data memory is changed correspondingly to a respective musical sound generators. An address control circuit converts the address corresponding to the key information into an address format in a location of the waveform data memory in which the desired waveform data is stored, and a data format converter circuit converts a data format of the desired waveform data readout from the waveform data memory so that the data readout from the waveform data memory is converted correspondingly to a respective one of the musical sound generators.

Abstract: A method of scaling a harmonic coefficient is employed, and envelope smaller in number than the number of harmonic orders are produced. One of the envelope is selected for each harmonic order and output as a scaling value. This enables the production of a musical tone imitative of a desired one, decreases the number of envelope generators needed, and permits simplification of the entire system configuration and signal processing.

Abstract: An electronic musical instrument having a number of keys, having tone generators capable of simultaneous tone production, the tone generators being smaller in number than the number of keys. The instrument forms an operation for synthesizing a desired waveform, the operation for synthesizing a desired waveform being performed in a repeating cyclic order with an operation cycle and in which the waveform is transferred to the tone generators and read out therefrom at a rate in accordance with the note of a key being depressed to obtain a desired musical waveform. The device includes a number-of-depressed keys detecting device which counts the number of keys which are actuating the tone generator upon depression. A cycle altering device is provided for changing the operation cycle, as a whole, on the basis of the number of depressed keys, counted by the number-of-depressed keys detecting device. The construction allows for a waveform of a smooth temporal variation to be produced.

Abstract: In the production of a desired musical waveform by combining harmonic components corresponding to respective harmonic orders, each harmonic component value is controlled by a selected cut-off harmonic order qc, level Ha and slope of the formant filter characteristic. The cut-off harmonic order qc, the level Ha and the slope values can each be varied over a predetermined range. Therefore, the slope values of the formant filter characteristic are interpolated to raise resolution, by which it is possible to prevent an abrupt change in the formant filter characteristic and suppress the generation of noise.

Abstract: In the production of a desired musical waveform by combining harmonic components corresponding to respective harmonic orders, the cut-off harmonic order q.sub.c, each harmonic component value is controlled by selecting the level Ha and the slope of the Formant filter characteristic. The cut-off harmonic order q.sub.c, the level Ha and the slope value can each be varied over a predetermined range. These operations can be performed with a simple circuit arrangement involving a small number of memories. Therefore, the present invention greatly contributes to the reduction of the size and the cost of electronic musical instruments.

Abstract: An electronic musical instrument is provided with a temporal variation circuit of SCF parameters for temporally varying the filter characteristic of a switched capacitor filter circuit, a control circuit for digitally controlling the temporal variation circuit and a touch response circuit for detecting, by scanning, touch response data in performance, whereby temporal variations of a musical waveform signal are digitally controlled.

Abstract: In an electronic musical instrument which generates a musical waveform by calculating the waveform amplitude value at each sample point through Fourier synthesis, note-range variations of the musical waveform and its timbre variations in accordance with a touch response are controlled with respect to readout addresses for reading out a set of harmonic coefficient data for the Fourier synthesis from a memory having stored therein a plurality of sets of such harmonic coefficient data, thereby changing the component ratio of a harmonic coefficient which will ultimately be used as a Fourier coefficient.

Abstract: In an electronic musical instrument which generates a musical waveform by calculating the waveform amplitude value at each sample point through Fourier synthesis, temporal variations of the musical waveform and its timbre variations in accordance with a touch response are controlled with respect to readout addresses for reading out a set of harmonic coefficient data for the Fourier synthesis from a memory having stored therein a plurality of sets of such harmonic coefficient data, thereby changing the component ratio of a harmonic coefficient which will ultimately be used as a Fourier coefficient.

Abstract: In an electronic musical instrument, note frequency data corresponding to a plurality of temperaments are prestored and are selectively read out in accordance with a selected one of the temperaments, generating a note frequency corresponding thereto. Further, a plurality of note frequency data corresponding to each transposition operation for each temperament and selectively read out in accordance with a selected temperament and the transposition operation, thereby generating a note frequency corresponding thereto. Thus the temperament selection and the transposition operation can be performed with satisfactory stability and high frequency accuracy.

Abstract: In an electronic musical instrument which generates a musical waveform by calculating the waveform amplitude value at each sample point through Fourier synthesis, there is provided a musical waveform generator for caculating and synthesizing a temporally varying musical waveform at a plurality of sample points, memory circuits for storing two kinds of musical waveforms obtained by the musical waveform generator one after the other and an interpolation circuit for interpolating the two musical waveforms at time intervals shorter than the time intervals used in the musical waveform generator.

Abstract: A tone synthesizing system which prevents the dynamic range from becoming unduly wide with an increase in the number of tone tablet switches being selected concurrently in an electronic musical instrument of the type synthesizing a musical sound through the use of a discrete Fourier transfer. In the electronic musical instrument in which, for obtaining a desired musical waveshape, amplitude values at its sample points are computed through the synthesizing system using the discrete Fourier transfer, harmonic coefficients of the tones selected or sine-wave values in accordance with the number of tone tablet switches being simultaneously selected are attenuated at a desired rate to limit a maximum level of an accumulated value of the harmonic coefficients or sine-wave values as predetermined.

Abstract: In an electronic musical instrument which obtains waveshape amplitude values at sampling points by calculation for producing a desired waveshape, there are provided first means for calculating a waveshape varying with time and second means for calculating a waveshape undergoing no variations with time. Normally the waveshape calculation by the first means is repeated but, in the case of a new key depression or a change in the state of a tone select switch, the waveshape calculation by the second means is performed.

Abstract: An electronic musical instrument in which harmonic coefficients stored corresponding to tablet signals are read out and synthesized by using a discrete Fourier transfer to form a desired musical sound. The format of cut back by a combination of a tone to be cut back, a key number and harmonic coefficient is predetermined, and based on the predetermined tone and key number respectively detected by tone detecting means and key number detecting means, the harmonic coefficient of the predetermined combination is read out, thereby to effect cutting back of the predetermined tone.

Abstract: An electronic musical instrument which is provided with a note frequency data memory for storing note frequency data corresponding to data of key switch depression through a key code register, a note frequency data register for latching and storing the data from the note frequency data memory by a time division pulse from a time division control signal generator, an octave data register for latching and storing octave data from the key code register by the time division pulse from the time division control signal generator, a frequency generator composed of a programmable counter supplied with the output from the note frequency data register to provide a frequency corresponding thereto, a frequency divider array supplied with the frequency and a decoder supplied with the output from the octave data register, the outputs from the respective output ends of the frequency divider array being selected by the output from the decoder in accordance with the octave data, and a musical waveform generator composed of fi