Abstract: A digital signal processing for, e.g., tone synthesis or tone control is performed by reading a microprogram from a microprogram memory and executing a digital signal processing algorithm according to this microprogram using necessary coefficients. A first coefficient to be used in this digital signal processing is supplied by a coefficient supply section but this first coefficient is not used directly for execution of the algorithm. A second coefficient which is actually used is generated as a result of a predetermined interpolation operation by a coefficient interpolation section using the first coefficient as a target value. The second coefficient which is used for execution of the algorithm, therefore, changes timewise toward the first coefficient. This coefficient interpolation section is provided independently from the microprogram.

Abstract: A reverberation effect imparting system includes plural comb filters, each of which has a signal delay line and a feedback loop for filtering a delayed output signal from the delay line and feeding the filtered signal back to the input side with a variable loop gain. The device further includes a junction section which receives the respective output signals from the delay lines of the plural comb filters. The junction section controls the received signals with respective variable scattering coefficients and sums up the thus-controlled signals, so as to introduce the summed signal into the feedback loop of each of the comb filters. In this manner, reverberation control according to the waveguide theory is performed by the junction section, while the conventional-type reverberation control is performed by the comb filters. Thus, reverberation can be controlled through a combination of the two controls.

Abstract: In a buffer memory are stored messages given to a specific task in order of arrival. Messages of same types may be stored in the buffer memory. In a different order from the order of arrival, a processing section performs task processing on the basis of the messages stored in the buffer memory. If two messages of a same type are present in the buffer memory, one of the messages which has arrived later than the other is processed with priority irrespective of the order of arrival, and the other message which has arrived earlier is deleted from the buffer memory. If there is present in the buffer memory such a message instructing transfer of parameters corresponding to a function that is not currently assigned, this message itself is deleted from the buffer memory as being ineffective, so as to process a next message.

Abstract: In a closed wave guide network having a bidirectional signal transmitting channel section and a signal junction section, signal delay time is variably controlled by a first parameter group so as to control the resonance frequency characteristics of the wave guide network. A signal excitor is connected to the wave guide network so that an excited signal is supplied to the network. The excitation frequency of the excitor is controlled in accordance with a second parameter group. There are also provided a combination determination section which, in correspondence to the pitch of a tone to be generated, determines a combination of the first parameter group to be used in the wave guide network and the second parameter group to be used in the excitor, and a parameter generator which, in accordance with the combination determined by the combination determination section, generates and supplies individual parameters of the first and second parameter groups.

Abstract: An electronic musical instrument simulating a wind instrument is fundamentally configured by a loop circuit at least containing a linear portion and a non-linear portion. The linear portion simulates a pipe portion of the wind instrument, while the non-linear portion simulates a breath-blowing portion of the wind instrument so as to produce an excitation signal, which is supplied to the linear portion. By an interaction between the linear portion and the non-linear portion which is carried out while a signal circulates through the loop circuit, a sounding characteristic of the wind instrument is simulated. In order to accurately simulate a jet reed instrument (e.g., organ pipe), there are further provided a delay circuit and an edge tone generator. The delay circuit imparts a delay time to the output signal of the linear portion, and then, a delayed signal is supplied to the non-linear portion.

Abstract: A musical tone synthesizing apparatus comprises a digital signal processor (i.e., DSP), a main memory and a sub memory. The main memory stores main instructions, while the sub memory stores sub instructions. In accordance with the main instructions and the sub instructions, the DSP performs several kinds of arithmetical operations in a time-division manner. Herein, the main instructions embody algorithms representing a sound source which contains a non-linear table. The contents of the non-linear table represents a non-linear characteristic of a musical instrument to be simulated. Values to be stored in the non-linear table are calculated in accordance with a predetermined mathematical computation utilizing a series expansion, a recurrence formula and the like. By rewriting the contents of the non-linear table, a non-linear characteristic to be applied to musical tone signals is altered in real time.

Abstract: A musical tone synthesizing apparatus includes a linear operation device, a non-linear operation device and a musical tone modification device. When the linear operation device receives a progressive wave signal, the device progresses and delays the signal, and outputs the progressed and delayed signal. The non-linear operation device varies the signal outputted by the linear operation device according to a musical tone control signal, and generates the varied signal as a new progressive wave signal. The musical tone modification device receives a plurality of signals extracted from the linear operation device or the non-linear operation device, creates a first signal and a second signal based on the plurality of signals, varying the first signal in accordance with the second signal, and provides the varied first signal as a musical tone signal to be synthesized.

Abstract: A time-changing coefficient digital filter having a data RAM for storing input data, a purality of N data registers at the output of the data RAM forming a delay element, a coefficient RAM storing coefficient values, coefficient registers temporarily storing respective coefficients, and a multiplier for multiplying data read out of data registers and coefficient registers respectively. Data from the multiplier and inputs is accumulated in an adder. Coefficient registers and data registers are updated by data from the data RAM and coefficient RAM. The coefficient digital filter provides a sum of products sequentially read out of the coefficient and data registers. The digital filter is applied to produce a musical instrumet having improved tonal qualities.