Abstract: Data of desired variable data length is stored in a memory. When desired data is to be taken out of the memory, data length of the data to be taken out is designated and necessary data is selectively taken out of the memory in accordance with the designated data length. Single data may be stored over plural addresses. In that case, MSB or LSB of data to be taken out of the data stored over the plural addresses is pointed out and desired data of a desired bit number is taken out in accordance with the pointed out position and the bit number of the data. In the memory, first data and second data may be mixedly stored. The second data consists of plural bits and is divided in plural sections, each section being separately stored in the first data. The first data and the second data are separated from the data which has been read from the memory and the respective sections of the second data are assembled together to reproduce completed second data.

Abstract: In order to deal with a large amount of data and achieve a high-speed data transfer, an electronic musical instrument employs the configuration providing with plural CPUs and one main memory (RAM) so that the memory is accessed by plural CPUs. Herein, each of the CPUs provides a specific data bus, so that each of them can receive and transfer data via the specific data bus. When performing a data transfer between each CPU and memory, a line connection is selectively established between the memory and selected one of the data buses, so that each CPU can easily perform a data transfer by accessing the memory via its data bus.

Abstract: A musical tone signal processor is included of a computation unit, a register, a controller and an interpolator, and imparts a variable acoustic effect to a musical tone signal. The computation unit repeatedly executes a cycle of computation steps applied to the musical tone signal, using a plurality of parameters so as to realize a desired acoustic effect. The register stores values of the respective parameters which are used individually in corresponding computation steps. The controller operates when a variation is requested in the acoustic effect for designating at least one registered parameter attributive to the requested variation so as to rewrite an old value of the designated parameter to a new value.

Abstract: A time-divisional data register comprises a shift register and a latch and is used for transferring data from a first apparatus operating at a relatively high speed to a second apparatus performing a time-divisional processing at a relatively low speed or long first period. The shift register operating at a second period shorter than the first period fetches data transmitted from the first apparatus with a designated time-divisional channel to which the data is to be assigned, stores the fetched data at a storage position corresponding to the designated channel and then outputs repetitively the stored data for each channel in turn at the second period. The latch latches the outputs from the shift register and outputs the latched data in synchronism with tile processing period of each channel in the second apparatus.

Abstract: To waveform data is applied not only a predetermined data compression processing but also a processing for further reducing the value of waveform data in accordance with a weight coefficient, which processing is performed at least at one stage selected from a stage before the data compression processing is performed, a stage when the data compression processing is being performed and a stage after the data compression processing has been completed. Data compression can thereby be performed to a further degree. A control for changing the rate of reduction or for not changing such rate at all can be made in a simple manner merely by changing the weight coefficient without changing the predetermined data compression processing system. Waveform sample data or tone control data consisting of multiple samples may be divided into plural sections each consisting of plural samples and a maximum value of effective bit number of sample data for each section may be detected.

Abstract: When a new tone is to be assigned to a certain channel, an amplitude level of a preceding tone signal which is being produced in this channel is detected and a damp rate is determined on the basis of the detected amplitude level. Tone volume of the preceding tone signal is rapidly attenuated in accordance with the damp rate thus determined and, thereafter, generation of a new tone signal is started. The damp rate thereby is variably controlled in accordance with the magnitude of tone volume level of the preceding tone signal during a damp control and both optimum prevention of a click noise and a very quick rapid attenuation control corresponding to the tone volume level can be realized. The invention is applicable not only to a damp control of tone volume of a tone but also to a damp control of an envelope shape signal used for other control purposes.

Abstract: An envelope waveform generation apparatus comprises an envelope waveform signal generator for forming an envelope waveform signal, a specific position setting member for setting a specific position, a position comparator and a key OFF controller. When a key OFF event is detected, the position comparator compares a position and/or level on the envelope waveform with those of the specific position, and the key OFF controller decays the level of the envelope waveform signal in the shape of a predetermined key OFF waveform, or delays key OFF processing by the envelope waveform signal generator on the basis of the comparison result.

Abstract: There are provided a waveform generating section for generating waveform sample data at a frequency corresponding a designated pitch, a coefficient generating section for generating n coefficients that correspond to a desired interpolation characteristic, a characteristic-controlling section for changing the coefficients to be generated in the coefficient generating section so as to variably control the interpolation characteristic, and an interpolation operation section for operating the coefficients with n digital waveform sample data generated sequentially from the waveform generating section and synthesizing operated data to produce one sample data. With this arrangement, it becomes possible to control the interpolation characteristic and therefore a resultant filter characteristic in accordance with a desired mode, when generating a tone signal of a smooth waveform by waveform interpolation operation utilizing digital filter operation.

Abstract: A series of delay circuits are provided which receive tone signal sample data of plural channels supplied on a time shared basis, hold plural tone signal sample data of each channel and hold these plural sample data while sequentially delaying them. The series of delay circuits are connected in an endless manner to form a circulating loop and plural data selection circuits are provided at predetermined delay stages. Each data selection circuit performs a selection control as to whether new tone signal sample data should be loaded in the delay circuit loop or data in the delay circuit should be circulated. Tone signal sample data which are provided sequentially from the delay circuit loop after delay are sequentially operated with filter coefficients of plural orders and results of the operation are accumulated to obtain a filter operation output.

Abstract: A musical tone generating apparatus generates musical tones based on a signal outputted from a sound source and an envelope generator. The signal outputted from the sound source is processed by a digital filter in accordance with filter information responsive to a key-on signal. Filter information generating circuit generates delay time information corresponding to the time period which the digital filter needs to process and output an inputted data. The envelope is imparted to the signal outputted from the sound source with a delay from a key-on timing which corresponds to the delay time information to realize precise envelope rise portions.

Abstract: The multi-recording apparatus of an electronic musical instrument pre-records performance information designated by event data representative of events of depressed or released keys and generation timings of the events. The performance information is recorded in a memory having a plurality of channels. When newly inputted performance information is supplied from the electronic musical instrument to this multi-recording apparatus in a recording mode, the pre-recorded performance information is reproduced from a selected channel, so that a player can listen to musical tones corresponding to the pre-recorded performance information. At the same time, the newly inputted performance information is over-recorded with the pre-recorded performance information on the same selected channel, whereby a multi-recording can be done.

Abstract: A musical tone signal is synthesized on the basis of a predetermined modulation operation (e.g. an FM or AM operation) employing a modulating signal and a carrier signal respectively having an audio range frequency. The modulating wave signal and/or carrier signal is derived by reading out a predetermined waveshape signal from a waveshape table in accordance with progressive phase angle data. The value of the waveshape signal read out from the waveshape table is modified in a specified phase section. This modification is effected by applying a simple operation such as gating, shifting or selecting to the phase angle data addressing the waveshape table or to the waveshape signal read out from the waveshape table. The modified waveshape signal is utilized in a predetermined modulation operation as the modulating wave signal and/or carrier signal.