JPS6034757B2 - electronic musical instruments - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an electronic musical instrument having a timbre change detection circuit that divides a group of timbre selection switches into a plurality of blocks, extracts only the blocks containing switches whose on/off state has changed, and performs waveform calculations. It is related to.

In a recently proposed digital electronic musical instrument, a key code is generated by a key switch, this key code is detected and assigned to a plurality of channels, and this key code and its corresponding envelope are input to a musical sound waveform generator.

On the other hand, a timbre selection detection circuit detects a timbre change based on the on/off state of a timbre selection doublet, drawbar switch, etc., a waveform calculation circuit calculates the waveform, and the output is sent to a musical waveform generator to synthesize a waveform based on the key code. Then, by adding an envelope, an acoustic signal output can be obtained. In this case, a conventional tone selection detection circuit that detects changes in the on/off state of tablet switches, etc. has been developed to scan all tablet switches by providing time slots, following the TDM or PCM method. etc., waveform calculations are performed for all switches, which poses a problem in that calculation time takes a long time. SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic musical instrument equipped with a timbre change detection circuit that can reduce the time required for waveform calculation by detecting changes in the on/off state of a timbre selection switch.

To achieve the above object, the electronic musical instrument of the present invention divides a group of tone selection switches into a plurality of blocks, and when there is a change in the on/off state of the tone selection switch, detects the block to which the changed tone selection switch belongs. block detection means 21 to 26 for detecting blocks, block code memory means 28 for storing block codes corresponding to blocks detected by the block detection means, and switch detection for detecting only tone selection switches in the ON state in the changed block. Means 27, 29, and 31 store a timbre code corresponding to the timbre selection switch detected by the switch detection means, and a write clock for storing the timbre code and a clock for reading the timbre code are asynchronous. timbre code memory means 30, and musical sound waveform calculation means 7 for reading a timbre code from the timbre code memory means and calculating a musical sound waveform from the timbre code, and storing the timbre code in the timbre code memory means. The block detecting means, the block code memory means, and the switch detecting means are actuated by a write clock for reading out the tone code from the tone code memory means.
The special feature is that the musical sound waveform calculation means is activated.

The present invention will be described in detail below with reference to examples.

First, an outline of an embodiment of a novel electronic musical instrument to which the present invention is applied will be explained, and then details of an embodiment of a tablet accelerator, that is, a timbre change detection circuit, which is the main part of the present invention will be explained.

An electronic musical instrument to which the present invention is applied gives information on extreme points on a musical sound waveform, approximates and reproduces the waveform, samples and stores this approximate waveform at a number corresponding to the frequency to be sounded, and repeats it at a predetermined clock. This is a digital electronic musical instrument that generates musical tones.

FIG. 1 is an overall explanatory diagram showing the configuration of an embodiment of an electronic musical instrument according to the present invention.

In the figure, key switch 1 on the keyboard is key assigner 2.
The on/off state is detected, and the key code corresponding to the key switch in the on state is assigned to and stored in a priority channel for sound generation.

When a certain channel is assigned and occupied by the keysigner 2, a time-division multiplied key-on signal is given to the envelope control circuit 3, and information on the state of the envelope (attack, decay, etc.) and its magnitude is converted into an envelope coefficient. Set as EC. Envelope coefficient E
C is converted into an envelope waveform amplitude by the envelope calculation circuit 4. On the other hand, the on/off state of the tablet switch 5 is detected by the tablet assigner 6, and if there is a change in the on/off state of the tablet switch, a signal to be newly calculated for the waveform and a signal representing the new on/off state of the tablet are added to the waveform. It is given to the calculation circuit 7.

Among the stored contents of the waveform information memory 8, the stored contents corresponding to the tablet in the ON state are sequentially read out, one cycle of the composite waveform is calculated by the waveform calculation circuit 7, and sent to the transfer control circuit 9. One cycle of the synthesized waveform is resampled by the transfer control circuit 9 to the number of words corresponding to the designated scale (note) of the occupied channel, and transferred to one occupied channel of the waveform register 10. The waveform register 10 is composed of a shift register whose number of words changes in accordance with the designated scale. The composite waveform read out from the waveform register 10 by the read clock 11 is time-division multiplexed between channels, and the envelope of each channel is added by an envelope adding circuit 12 to divide the time-division multiplexing between channels.
Cumulative addition is performed in the accumulator 13 every cycle,
A digital-to-analog converter (DAC) 14 extracts the signal as an analog audio signal. FIG. 2 is a detailed explanatory diagram of an example of a tablet assigner 6 including the tablet switch 5 of FIG. 1, which is a main part of the present invention. In the figure, a clock J3 from a clock generator 21 is used to calculate a tablet code counter 22 according to the on/off state, and further, a block code obtained by dividing these tablets into a plurality of blocks is counted.

In this case, the blocks can be divided into upper manual, lower manual, and pedal, or they can be divided into several parts. The block code is a code assigned to identify this block.
The tablet counter 22 and the block counter 23 are repeatedly counted, and for each period, the on/off state of the tablet switch is sampled by two sampling clock generation circuits and connected in parallel to one of each of these tablet switches. Simultaneously write to shift register 24 with clock? 3, the shift register 24 and delay shift register 25 connected in series are shifted, and the output of the shift register 24 and the output of the shift register 25 are compared by an exclusive OR gate 26. In on-off state sampling, different signals at two sample points means that the tablet is turned on or off between the two points. Therefore, exclusive PR gate 2 indicates that the output signals of shift register 24 and shift register 25 are different.
6, the block code of the block to which the tablet that has changed belongs is written from the block code counter 23 to the event block register 28. The event block register 28 is composed of a FIFO memory that operates as an asynchronous buffer memory. When the tablet is turned on and off in several blocks, the blocks that turn on and off earlier are processed sequentially.The output of the event block register 28 is compared with the block code in the comparison circuit 29, and the output of the event block register 28 is
Issue a match signal in the time slot of the block code equal to the output of 8.

By inverting this match signal and inputting it to the reset (R) terminal of the flip-flop 31, it is set by the empty signal of the calculation block code register 30, which will be described later, and is set by the trailing edge of the match signal from the first comparison circuit 29. will be reset. This flip-flop 31
During the time slot created by the set and reset of , the tablet codes of all tablets turned on in the block by the tablet signal from shift register 24 are written into calculation block code register 301 through AND gate 27 . The tablet code written in the register 30 is sequentially read out by a read signal from the waveform calculation circuit 7 shown in FIG. This calculation block code register 30 is a FIF which is an asynchronous buffer memory.
The read signal does not need to be synchronized with the clock 3. This calculation block code register 30
When the output code is read out and the stored contents are exhausted, the next block code is output from the event block register 28 by an empty signal. That is, after the waveform calculation circuit 7 of FIG. 1 finishes calculating the waveform of each block, the block code is calculated. As explained above, according to the present invention, a tablet switch, generally a timbre selection switch, is divided into multiple blocks, only blocks with an on-off change are detected, and only the on-state timbre code of that block is extracted. By performing waveform calculations,
Compared to the conventional method of calculating waveforms by scanning all timbre selection switches, calculation time can be significantly reduced. In addition, in the embodiment, the shift register connected in parallel to each tablet switch is clocked? 3
By sampling with , it is possible to generate a time-division multiplexed tablet code more easily than with the conventional TDM method.

Furthermore, by temporarily storing the tablet code time-division multiplexed with the clock signal J3 in the Fm0 memory IJI of the asynchronous buffer memory, there is no need to synchronize the processing in the subsequent stage with the clock J3 in the previous stage, increasing the degree of freedom in design.

In the latter two cases, the structure proposed in a separate application for the key assigner 1 of the keyboard circuit shown in FIG. 1 is applied.

[Brief explanation of drawings]

FIG. 1 is an overall explanatory diagram showing the configuration of an embodiment of an electronic musical instrument of the present invention, and FIG. 2 is a detailed explanatory diagram of an example of a tablet assigner which is a main part of the present invention in the embodiment of FIG. 1. and
In the figure, 1 is a key switch, 2 is a key assigner, 3 is an envelope control circuit, 4 is an envelope calculation circuit, 5 is a tablet switch, 6 is a tablet assigner, 7 is a waveform calculation circuit, 8 is a waveform information memory, and 9 is a Transfer control circuit, 1
0' is a waveform register, 11 is a start clock, 12 is an envelope addition circuit, 13 is an accumulator, 14 is a digital-to-analog converter, 21 is a clock, 22 is a tablet code counter, 23 is a block code counter,
24 is a shift register, 25 is a delay shift register, 2
6 is an exclusive OR gate, 27 is an AND gate, 28 is an event block register, 29 is a comparison circuit, 30 is a calculation block code memory, and 31 is a flip-flop. Figure 1 Figure 2

Claims (1)

[Claims] 1 Divide the timbre selection switch group into multiple blocks, and if there is a change in the on/off state of the timbre selection switch,
Block detection means 21 to 26 for detecting the block to which the changed timbre selection switch belongs; block code memory means 28 for storing the block code corresponding to the block detected by the block detection means; switch detection means 27, 29, and 31 for detecting only the tone selection switch in the on state, and storing the tone color code corresponding to the tone selection switch detected by the switch detection means, and for storing the tone color code. timbre code memory means 3 in which the writing clock of the timbre code and the clock for reading the timbre code are asynchronous;
0, and musical sound waveform calculating means 7 for reading out a musical tone code from the musical tone code memory means and calculating a musical waveform according to the musical tone code, and a write clock for storing the musical tone code in the musical tone code memory means,
The block detection means, the block code memory means, and the switch detection means are operated, and the tone waveform calculation means is operated by a clock for reading the tone code from the tone code memory means. electronic musical instrument.