JP2900463B2 - Musical instrument for electronic musical instruments - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a musical sound generator for an electronic musical instrument that calculates musical sound data in synchronization with an external synchronization signal and generates musical sounds.

2. Description of the Related Art In recent years, musical sound generation of electronic musical instruments has been performed by digital arithmetic, and mixing of sounds of a plurality of musical instruments and addition of effects such as reverb and equalizing to musical sounds have also been performed by digital arithmetic. It has become to. However, if the tone generator and the effect adding device (including the mixing in this case) are separate devices, the tone generator once converts the tone from a digital signal to an analog signal, and then converts the analog signal again into an analog signal. The processing of returning from a signal to a digital signal has been performed. For this reason, deterioration of the tone quality and S / N ratio (ratio of signal to noise) of the musical tone was inevitable. In order to prevent this deterioration from occurring, the musical sound may be sent from the musical sound generating device to the effect adding device as a digital signal. In order to transfer musical tones as digital signals, the operation of the musical tone generator and the effect adding device must be synchronized. There are the following two methods for this.

One is a method of supplying a basic clock signal, which is a minimum time unit of an arithmetic operation, from one device to another device. All arithmetic operations are integral multiples of the period of the basic clock signal. If the two devices are operated at the same integral multiple of the period of the basic clock signal, musical tone data can be transferred as digital signals. it can. However, the frequency of the basic clock signal is usually 10 [MHz] or more, and it is not practical to pass such a high-frequency signal between two devices. This is because the unnecessary radiation of the electromagnetic wave becomes extremely large, adversely affecting other electronic devices such as malfunctions, or the waveform of the basic clock signal is distorted due to the load capacity of the signal line, and the device does not operate normally. Because.

The other is a method in which the basic clock signal is separately generated in two devices, and a synchronization signal for synchronizing a sampling cycle is supplied from one device to the other device. The frequency of the synchronization signal may be the same as the sampling frequency, which is usually several tens [kHz], so that the problem that occurs in the former method does not occur. Assuming that a synchronization signal is sent from the effect adding device to the tone generator, the tone generator terminates the calculation of the tone data in a time shorter than the sampling period, and then has the synchronization signal. When the synchronization signal is sent, the tone generator returns. An arithmetic operation of continuing data calculation is performed. In this way, the sampling periods of the two devices coincide, and the musical sound data can be transferred as digital signals. Therefore, the latter method is actually used.

Hereinafter, a description will be given of a conventional tone generator which can be synchronized with an external synchronization signal. Here, the term “channel” is a term for distinguishing a plurality of tones when a plurality of tones are generated.
It is used as “the operation period of the 0th channel”.
Further, “channel” is abbreviated as “ch” and is expressed as 0ch (representing the 0th channel).

FIG. 3 is a block diagram of a conventional tone generator. In FIG. 3, reference numeral 22 denotes a pitch calculator for calculating an address change width ΔAD based on a pitch of a musical tone to be played, and 23 accumulates the address change width ΔAD for each channel to obtain an address AD.
, An address latch for latching the address AD and supplying it to the waveform memory, 25 is a waveform memory, 26 is an envelope arithmetic unit for calculating envelope data ENV, and 27 is read from the waveform memory 25. The multipliers 28, 29, 30, and 31 each multiply the resulting waveform data WD by the envelope data ENV and output the result as tone data W.
The tone data latch 21 latches the tone data W of channels 0, 1, 2, and 3; 21 suspends the computation based on the tone computation end signal and resumes the computation based on the synchronization signal; This is an arithmetic control unit that gives instructions.

Regarding the musical sound generator configured as described above,
The operation will be described below with reference to the operation timing chart of FIG.

First, an external synchronization signal (FIG. 4 (a)) is "0".
From “1” to “1”, the arithmetic control unit 21 generates an arithmetic clock signal ((b)) for operating each arithmetic unit and generates a pitch arithmetic start signal ((h)) for one clock of the arithmetic clock signal. It becomes "1" only for the period. When the pitch calculation start signal becomes "1", the pitch calculation unit 22 starts from the 0th channel, and proceeds to the first, second, and third channels in order from the waveform memory 25 based on the preset pitch of each channel.
, An address change width ΔAD for updating the address AD from which the waveform data WD is read every sampling period is calculated. For example, if the pitch is represented by two variables, a pitch CENT within one octave expressed in cents, and an octave OCT, the address change width ΔAD is calculated as ΔAD = k * 2 ^{CENT / 1200} * 2 ^OUT You. Here, k is a constant that depends on the sampling period and the number of points in one period of the waveform data WD.
The timing chart of the pitch calculation in FIG. 4 (c) shows the channel where the pitch calculation is being performed, and shows that the pitch calculation of the 1, 2, and 3 channels is performed after the 0th channel. . When the pitch calculation of the third channel is completed, the pitch calculator 22 enters a state called “NOP state”. The NOP state is a calculation state in which the result calculated at that time does not affect the tone data. After the NOP state, the state changes to the “WAIT state” described later.

Next, the address change width ΔAD output from the pitch calculating unit 22 is accumulated for each channel in the address calculating unit 23 and output as an address AD ((d)). That is, the calculation of “AD = ΣΔAD” is performed.

Next, the address latch 24 latches the address AD and outputs it to the waveform memory 25. The waveform memory 25
The waveform data WD corresponding to the latched address AD is output. While the waveform data WD is being read from the waveform memory 25, the envelope calculation unit 26 calculates the envelope data ENV ((e)).

Next, in the multiplication unit 27, the waveform data WD and the envelope data ENV are multiplied and output as the musical sound data W ((f)). The tone data of the 0th channel is latched by the tone data latch 28, and the tone data of the first, second, and third channels are latched by the tone data latches 29, 30, 31 ((i)).

Address operation unit 23, address latch 24, waveform memory 25,
When the arithmetic operation of the third channel is completed, the envelope arithmetic unit 26 enters the NOP state next. When the calculation of the third channel is completed in the multiplier 27, the tone calculation end signal ((g)) indicating that the tone calculation of all channels within one sampling period has been completed is changed from "0" to "1".
The operation control unit 21 stops the operation clock signal. When the operation clock signal stops, the pitch operation unit 22, the address operation unit 23, the address latch 24, the waveform memory 25, the envelope operation unit 26, and the multiplication unit 27 stop the operation. This state is called “WAIT state”, and the period of the WAIT state is called “WAIT time”. The WAIT state continues until the next synchronization signal is generated (in this case, a change from “0” to “1”).

When the synchronization signal changes from “0” to “1”, the arithmetic control unit
At 21, an operation clock signal is generated again, and a pitch operation start signal becomes "1", and the operation for generating a musical tone is restarted. The address operation unit 23, the address latch 24, the waveform memory 25, the envelope operation unit 26, and the multiplication unit 27
The NOP state is maintained until data for the calculation of the next channel 0 is input.
The arithmetic operation is performed in the order of the second and third channels.

In this way, a total of 4
Music data for the channels is calculated. In this case, the calculation cycle, that is, the sampling cycle is (sampling cycle) = (calculation clock signal cycle) * 7 + (WAIT time).

However, in the above-described conventional configuration, the operation clock signal is stopped after the completion of the operation of the musical tone data of all the channels, and the next operation is performed until the next synchronization signal is generated. There is a problem that a wasteful state occurs, and the time required for calculating the tone data increases as compared with a case where the sound data is not synchronized with an external synchronization signal. When not synchronizing with an external synchronization signal, the operation timing chart is as shown in FIG. 3, and the sampling period is (sampling period) = (operation clock signal period) * 4. The sampling cycle when synchronizing with an external synchronization signal is (calculation clock signal cycle) * 7 +
(WAIT time), which is about twice as long as the case without synchronization. As a result, when synchronized, the sampling frequency is reduced to about half compared with the case where synchronization is not performed, and there is a problem that a musical tone having a high frequency component cannot be generated.

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned conventional problems, and to provide a tone generator which operates at substantially the same sampling cycle as when not synchronized with an external synchronization signal and which can be synchronized with an external synchronization signal. With the goal.

Means for Solving the Problems In order to achieve this object, a musical sound generating apparatus for an electronic musical instrument according to the present invention, according to the first aspect of the present invention, controls the operation of a plurality of arithmetic units for performing arithmetic processing of musical sound data in order. An arithmetic control unit that controls the arithmetic unit stops arithmetic operations of the plurality of arithmetic units before finishing the arithmetic unit for the musical sound data for one sampling period before the arithmetic unit that performs arithmetic operation on the musical tone data last among the plurality of arithmetic units is synchronized. It is characterized in that a plurality of arithmetic units restart arithmetic processing in synchronization with a signal.

In this way, the arithmetic unit that performs the arithmetic operation on the musical tone data last among the arithmetic units stops the arithmetic operations of the multiple arithmetic units before completing the arithmetic operation on the musical sound data for one sampling period, and synchronizes with the synchronization signal. Since the arithmetic processing is restarted by the plurality of arithmetic units, the occurrence period of the wasteful state such as the NOP state described in the related art can be reduced.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a tone generator according to an embodiment of the present invention. In FIG. 1, reference numeral 2 denotes a pitch calculator for calculating an address change width ΔAD based on a pitch of a musical tone to be generated, and 3 denotes an address calculator for calculating the address AD by accumulating the address change width ΔAD for each channel. 4 is an address latch for latching the address AD and supplying it to the waveform memory, 5 is a waveform memory, 6 is envelope data
Envelope calculator for calculating ENV, 7 is waveform memory 5
Waveform data WD and envelope data
Multiplying unit for multiplying ENV and outputting it as musical sound data W, 8, 9, 1
Reference numerals 0 and 11 denote musical tone data latches for latching the musical tone data W of the 0th, first, second and third channels, respectively, and 1 a temporary stop of the arithmetic operation based on a pitch operation end signal and a temporary stop of the arithmetic operation based on a synchronization signal. The operation control unit instructs each operation unit to restart.

Regarding the musical tone generator configured as described above,
The operation will be described below with reference to the operation timing chart of FIG.

First, an external synchronization signal (FIG. 2 (a)) is "0".
From “1” to “1”, the arithmetic control unit 1 generates an arithmetic clock signal ((b)) for operating each arithmetic unit, and generates a pitch arithmetic start signal ((h)) for one arithmetic clock signal. It becomes "1" only during the period. When the pitch calculation start signal becomes “1”, the pitch calculation unit 2 reads the waveform from the waveform memory 5 based on the preset pitch of each channel in the order of channel 0, first, second, and third. An address change width ΔAD for updating the address AD for reading the data WD for each sampling cycle is calculated ((c)).

Next, the address change width ΔAD output from the pitch calculator 2 is accumulated for each channel in the address calculator 3 and output as an address AD ((d)). Also in the address calculation unit 3, the calculation is performed in order from the 0th channel to the first, second, and third channels for each cycle of the calculation clock signal. When the pitch calculator 2 is performing the calculation of the first channel, the address calculator 3 is performing the calculation of the 0th channel, so that the address calculation is performed one channel later than the pitch calculation. .

Next, the address latch 4 latches the address AD and outputs it to the waveform memory 5. The waveform memory 5
The waveform data WD corresponding to the latched address AD is output. At the same time as reading the waveform memory, the envelope calculation section 6 calculates the envelope data ENV ((e)). The reading of the waveform memory and the envelope calculation are performed one channel after the address calculation and two channels after the pitch calculation.

Next, in the multiplication unit 7, the waveform data WD and the envelope data ENV are multiplied and output as musical sound data W ((f)). The multiplication is performed with a delay of one channel for reading the waveform memory and for the envelope calculation and three channels for the pitch calculation. The tone data W is latched by tone data latches 8, 9, 10, and 11 for the 0th, 1st, 2nd, and 3rd channels, respectively ((i)).

When the calculation of the third channel is completed in the pitch calculation section 2, the pitch calculation end signal ((g)) indicating that the pitch calculation of all channels has been completed changes from “0” to “1”, and the calculation control section 1 Stops the operation clock signal. Since the calculation clock signal is stopped, the pitch calculation unit 2 is on the third channel, the address calculation unit 3 is on the second channel,
The address latch 4, the waveform memory 5, and the envelope operation unit 6 suspend the respective operation at the time of completion of the operation of the first channel and the multiplier 7 at the end of the operation of the 0th channel. That is, the above-mentioned WAIT state is established without going through the wasteful state of the above-mentioned NOP state.

Next, when the synchronization signal changes from "0" to "1", the arithmetic control unit 1 operates the arithmetic clock signal again, and sets the pitch arithmetic start signal to "1" for a period of one arithmetic clock signal. . As a result, the pitch calculator 2 calculates the 0th
The arithmetic operation of the channel is started, the address arithmetic unit 3 restarts the arithmetic operation from the third channel, the address latch 4, the waveform memory 5, and the envelope arithmetic unit 6 restart the arithmetic operation from the second channel, and the multiplier 7 restarts the arithmetic operation from the first channel. Further, in the interval calculation section 2, the interval calculation end signal becomes “0”. In the operation section restarted from the operation of the channels other than the 0th channel, the operation of the 0th channel is performed after the operation of the 3rd channel.

In this way, a total of 4
The tone data of the channel is calculated. The calculation cycle of the present embodiment, that is, the sampling cycle is (sampling cycle) = (calculation clock signal cycle) * 4 + (WAIT time), and has a WAIT time, that is, a synchronization signal, as compared with the case where the synchronization signal is not synchronized. Only during this period, the sampling period is increased, and the time is (operation clock) * 3 shorter than in the conventional example.

It is to be noted that temporarily stopping the arithmetic operation means maintaining the stopped state as it is, so that the arithmetic operation is resumed from the stopped state, and as a result, there is no inconvenience in generating a musical tone due to the stop of the arithmetic operation. .

As described above, according to the present embodiment, even if the calculation of the tone data of all channels is not completed, the calculation is temporarily stopped, and the calculation is resumed in synchronization with an external synchronization signal, so that the sampling period can be reduced. With little increase
Calculation of musical sound data synchronized with an external synchronization signal becomes possible.

In the present embodiment, the WAIT state is set at the end of the pitch calculation of the third channel, and the calculation is restarted by the synchronization signal. However, the state is changed to the WAIT state at an arbitrary fixed point, and the calculation is restarted by the synchronization signal. The same effect can be obtained by doing so.

Effect of the Invention As described above, in the present invention, since the occurrence of a wasteful state such as the NOP state described in the related art can be suppressed,
It is possible to calculate tone data in synchronization with an external synchronizing signal without substantially increasing the sampling period, and to send the tone data as an digital signal to an external device that supplies the synchronizing signal.

[Brief description of the drawings]

FIG. 1 is a block diagram of a tone generator according to an embodiment of the present invention, FIG. 2 is an operation timing chart of the tone generator of FIG. 1, and FIG. 3 is a conventional tone generator synchronized with an external synchronization signal. FIG. 4 is a block diagram of the device, FIG. 4 is an operation timing diagram of the conventional tone generator of FIG. 3, and FIG. 5 is an operation timing diagram of the conventional tone generator not synchronized with an external synchronization signal. 1 arithmetic control unit, 2 pitch arithmetic unit, 3 address arithmetic unit, 4 address latch, 5 waveform memory, 6
... Envelope calculation unit, 7 Multiplication unit, 8, 9, 10, 11 ...
… Tone data latch.

Claims (2)

(57) [Claims] 1. A musical tone generator for an electronic musical instrument for generating musical tones after calculating and outputting musical tone data in synchronization with a synchronization signal periodically inputted from the outside, wherein said musical tone data is sequentially processed. A plurality of calculation units, and a calculation control unit that controls operations of the plurality of calculation processing units, wherein the calculation control unit is one of the plurality of calculation units that performs last calculation processing on the musical tone data. The electronic musical instrument according to claim 1, wherein the arithmetic processing of the plurality of arithmetic units is stopped before the arithmetic operation on the musical sound data for the sampling period is completed, and the arithmetic processing is restarted by the plurality of arithmetic units in synchronization with the synchronization signal. Musical sound generator. 2. The musical tone generating apparatus for an electronic musical instrument according to claim 1, wherein the arithmetic unit that first processes the musical tone data among the plurality of arithmetic units finishes the arithmetic operation on the musical tone data for one sampling period. A musical tone generation device for an electronic musical instrument, which outputs an arithmetic end signal notifying the end of the arithmetic processing to the arithmetic control unit at a point in time.