JPS6118757B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a waveform data transfer method for an electronic musical instrument in which waveform data is transferred to a waveform storage circuit using a clock that is an integral multiple of the readout clock corresponding to the octave of the pressed key or a readout clock for the highest octave of the same note name. It is related to. Conventionally, the waveform data calculated in an electronic musical instrument is played back as musical tones in two ways: one is to play the calculated waveform data in real time, and the other is to transfer it to a buffer such as a waveform memory circuit and write it into a buffer. There is a method for reproducing the contents. In the latter case, there are known methods to transfer data from the waveform calculation circuit to the waveform storage circuit relatively slowly using the same clock as the readout clock, and methods to transfer the data using an asynchronous high-speed clock independent of the readout clock. It is being However, the method of transferring data using the same clock as the read clock simplifies the circuit because both clocks are the same and does not require a write-only clock, but since there are multiple waveform storage circuits to which the data is transferred, If you press all 12 keys in the lowest octave at the same time, the transfer clock will also have a low frequency, and it may take several tens of ^m3 (milliseconds) for the last key to be transferred and sounded, which may interfere with your performance. Become. Therefore, it is desirable that the transfer speed be high. In addition, with the method of transmitting data using an asynchronous high-speed clock, the waveform is rewritten at high speed even while the key is being pressed, so if the tablet or drawbars are changed midway through, a harsh noise will be produced, and a doubling ensemble effect will occur. In cases where the waveform changes over time, such as in the sliding formant effect, the waveform is frequently rewritten, making it extremely difficult. Furthermore, since a separate circuit for high-speed transfer is provided, it becomes complicated. The present invention eliminates the above-mentioned conventional drawbacks, and its purpose is to provide a waveform data transfer method for electronic musical instruments that performs high-speed transfer without using complicated circuits and does not generate noise during readout. That's true. In order to achieve the above object, the waveform data transfer method of the present invention is an electronic clock that transfers calculated waveform data to a waveform storage circuit, and reads out the contents of the waveform storage circuit with a clock proportional to the sound frequency of the pressed key. In the waveform data transfer method for musical instruments, for the same note name, the contents of the waveform storage circuit are read out using the readout clock corresponding to the octave of the pressed key, and the contents of the waveform storage circuit are read out using the readout clock corresponding to the octave of the pressed key, and the contents of the waveform storage circuit are By time-divisionally executing the transfer of the waveform data at separate timings using a clock, an integral multiple of the number of waveform data is transferred within one clock period of the readout clock. . The present invention will be described in detail below with reference to examples. FIG. 1 is an overall schematic explanatory diagram of an electronic organ using a waveform storage circuit to which the present invention is applied. In the figure, the entire system is time-divisionally controlled by a time-division control circuit 2. A key code signal consisting of a note name code and an octave code from the keyboard circuit 1 is inputted to the waveform storage circuits 5 ₁ to 5 ₁₆ and the waveform calculation circuit 3,
In the waveform memory circuits ₅₁ to ₅₁₆ , one clock is selected from the pitch name code and the octave code pressed by the basic clock from the basic clock generation circuit 4, and the waveform calculation circuit uses this clock as an address. A musical waveform is read out from a random access memory (RAM) in which the waveform data transferred from 3 is stored, and synthesized by a D/A converter 7. On the other hand, the attack signal from the keyboard circuit 1 is input to an envelope circuit 6 to form a predetermined envelope signal, which is applied to a D/A converter 7. After giving an envelope to each musical sound waveform, the attack signal is synthesized and sent to an amplifier 8. A musical tone signal is taken out from the output end 9 via. FIG. 2 shows the internal configuration of the waveform storage circuits 5 ₁ to 5 ₁₆ of the electronic organ shown in FIG. 1, which constitute the main part of the present invention. FIG. 3 shows the time chart of this waveform storage circuit. The following will be explained in accordance with FIG. 2 and with reference to FIG. 3. In Figure 2, the 4-bit note name code from keyboard circuit 1 is input to the data selector (12 inputs/1 output).
11, select which note name of the basic clock (C, C#, D, D#, ..., B) was pressed, and select the selected third note name from the Q output.
The clock shown in the figure is divided by 7 by the counter 12, and the third
The Q ₀ to _{Q 5} outputs shown in FIGS. b to g are sent to the data selector (6 inputs/1 output) 13. The data selector 13 inputs the octave code from the keyboard circuit 1, and determines which octave (second, second,
3rd, ..., 7th octave). Table 1 shows the pitch name code corresponding to the pitch name, the pitch name clock (KHz) of the 7th octave (equivalent to 64 times the pitch name frequency of the 7th octave), and the corresponding basic clock (KHz) [i.e. This corresponds to four times the pitch name clock of seven octaves]. This table is an example in which one period of the waveform is formed by 64 sample points. Furthermore, Table 2 shows the relationship between octave codes and octave names. Now, to explain the operation using an example, for example, if the E key of the fourth octave is pressed, the note name code: "0100", the octave code;
"011", the data selector 11 selects the basic clock (675.072KHz) corresponding to the E key, this is divided by the 7-stage counter 12, and the data selector 13 selects the Q ₃ output of the counter 12. The signal is selected and becomes the input to the six-stage counter 14 as the signal. This 6-stage counter 14 divides the signal, and these

【table】

[Table] Random access memory (RAM) in which the waveform data of the frequency division output is stored [capacity 12 bits x 64]
By setting the address to 16, the latch circuit 17
The musical sound waveform is read out through the Data selector (2 input/1 output x 6) 15 is
It is used to control the address of RAM 16 in a time-division manner. That is, the signal is obtained by passing the Q ₀ output signal of the counter 12 and the Q output signal of the data selector 13 through the OR circuit 21 (FIG. 3).
While the signal is at a low level, the divided outputs Q ₀ to _{Q 5} of the 6-stage counter 14 are input to the data selector 15 as input I ₀
~I ₅ , and output Q ₀ ~Q ₅ to RAM16.
The RAM ₁₆ reads out the waveform data using a _clock proportional to the musical waveform. This situation is shown as a read address of the RAM 16 in FIG. While the signal is at a high level, the frequency-divided outputs Q ₁ to _{Q 6} from the seven-stage counter 12 are input as inputs I' ₀ to I' ₅ to the data selector 15, and similarly, the outputs Q ₀ to Q ₅ are input to the RAM 16. address
Enter Ad ₀ to Ad ₅ . These addresses enable the waveform calculation circuit to transfer and write waveform data. This situation is shown as the write address of the RAM 16 in FIG. 3 (FIG. 2). Further, the signal is given to the latch circuit 17 by passing the Q output signal of the data selector 11 and the output signal of the OR circuit 21 through the OR circuit 23, and latches the waveform data output from the RAM 16. A waveform is obtained, but as shown in FIG. 3, since the signal is a signal at this time, the latch circuit 17 latches the same waveform data four times at a time, and the address advances. This will become clear when comparing the changes in the read address of the RAM 16 in FIG. 3. This is because this example assumes that the fourth octave is pressed, and if it is assumed that the fifth octave is pressed, the signal becomes a signal, and the signal becomes a signal, so the fourth octave is The read address advances twice as much as when the key is pressed, and the address advances while latching the same waveform data twice. Also, if the third octave is pressed, the signal becomes a signal, and the signal becomes a signal, so the read address progresses by 1/1 compared to when the fourth octave is pressed.
The address is doubled and the same waveform data is latched eight times at a time as the address advances. This is because the circuit is based on a simplified circuit example, and it is possible to latch one waveform data only once by adding some circuits. As described above, the read address of the waveform data is determined by the signal obtained by dividing the clock of the signal shown in FIG. On the other hand, transfer of waveform data and write address are performed via a 7-stage counter 12 and a data selector 15 using a signal obtained by dividing the clock of the highest 7th octave signal in this system by the counter 12, and the timing is as follows. Figure 3
RAM16 write address (Figure 2) and RAM
As clearly indicated by the read address No. 16, time-sharing processing is performed so that the influence of writing does not appear during reading, and high-speed transfer is possible.
(For example, when reading the first address at t ₁ , the first address data has already been written and updated at t ₀ , and when reading the second address at t ₂ , the second address data has already been written and updated at t ₀ , and so on. (The same applies hereinafter.) In this way, while the waveform data is read out from the RAM 16 and the sound is being generated, the waveform calculation circuit (Fig. 1)
When a waveform data transfer request signal is input to the latch circuit 18, the data selector 15 selects the RAM1
6, a write address is specified at a timing provided separately from the read address, and new waveform data is written using the note name clock of the seventh octave of the E note, that is, a clock proportional to the sound generation frequency, so that no adverse effect appears on the readout. In order to create that timing, data selector 1
1 and the inverted signal of the _Q0 output signal of the 7-stage counter 12 through the inverter 20.
The signal shown in Fig. 3 obtained through the OR circuit 22 is
On the other hand, the waveform data transfer request signal is input to the D terminal of the latch circuit 18 consisting of a D-type flip-flop, and the _Q6 output of the seventh stage of the seven-stage counter 12 is an inverted signal obtained via the inverter 19. is applied to the clock (CK) terminal, and the signal shown in Figure 3 is output as the read/write signal of RAM16.
Add to the light (R/W) terminal. That is, the output signal is set to a low level at the timing when the seven-stage counter 12 becomes all "0". Therefore, the output signal of the OR circuit 24 is added only during the period when this signal is at a low level, making it possible to write new waveform data. Furthermore, since the write timing is different from that of the signal that latches the latch circuit 17, there is no mutual influence between the signals and the signal that latches the latch circuit 17. When the waveform calculation circuit (Fig. 1) sends out the waveform data of 64 sample points, the latch circuit 18 lowers the waveform data transfer request signal to a low level, so that the latch circuit 18 detects the falling edge of the _Q6 output of the 7-stage counter 12. latches this input signal and the output signal returns to high level. This situation is shown in FIG. In the embodiment shown in Fig. 2, the highest octave readout clock (signal in this case) available in the system is used to write waveform data, but if an integral multiple of the clock corresponding to the key press can be obtained, this can be used. The waveform data may also be written using the . FIG. 4 is an explanatory diagram showing the configuration of another embodiment of the present invention, in which a clock of an integer multiple according to the above-mentioned key presses is applied. The difference in this figure from the embodiment shown in FIG. 2 is that the waveform data read signal input by the data selector 15 is input to the input and output Q 0 of the 6-stage counter 14 instead of the outputs Q ₁ to Q ₆ of the 7-stage counter _12. ~ _Q4 are the inputs _I0 ~ _I5 of the data selector 15, respectively, and outputs _Q0 ~ _Q5 are the inputs _I'0 ~ _I'5 of the data selector 15, respectively.Therefore, the read clock and write clock So 1
This results in an order of magnitude difference, that is, a two-fold difference. In this case, the transfer speed is 1/4 compared to the configuration shown in Figure 2.
[See the write address of the RAM 16 in FIG. 3 (FIG. 4)], but it is still twice as large as the conventional method of transferring using the pitch name clock. In this way, it is generally possible to perform transfer and writing using a clock that is an integral multiple of the pitch name clock that is pressed. As explained above, according to the present invention, calculated waveform data is transferred to the waveform storage circuit,
In the method of reading out the contents of the memory circuit using a clock proportional to the sound frequency, for the same note name, the contents of the waveform memory circuit are read out using the readout clock of the octave that was pressed, and if the same note name is read out by an integral multiple of this clock or the same note name. The waveform data is transferred using the readout clock of the highest octave in a time-division manner. Using this method enables high-speed transfer, and also eliminates noise during transfer because the data is transferred in a time-sharing manner and the write clock is set at a different timing from the readout in synchronization with the waveform data readout clock. The advantage of electronic musical instruments is that they do not require a separate high-speed clock for writing, the timing signals required for both can be easily obtained from the same oscillation source, and there are many signals that can be used in common. A waveform data transfer method can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic explanatory diagram of an electronic organ to which the present invention is applied, FIG. 2 is an explanatory diagram showing the configuration of an embodiment of the present invention, and FIG. 3 is a time chart showing the operation of the embodiment of FIG. 2. , FIG. 4 is an explanatory diagram showing the configuration of another embodiment of the present invention, in which 1 is a keyboard circuit, 2 is a time division control circuit, 3 is a waveform calculation circuit, and 4 is a diagram showing the configuration of another embodiment of the present invention.
1 is a basic clock generation circuit, ₅₁ to ₅₁₆ are waveform storage circuits, 6 is an envelope circuit, 7 is a D/A converter, 8 is an amplifier, 11, 13, and 15 are data selectors, 12 and 14 are counters, and 16 is a Random access memory (RAM), 17 and 18 indicate latch circuits.

Claims (1)

[Claims] 1. A waveform data transfer method for an electronic musical instrument in which calculated waveform data is transferred to a waveform storage circuit, and the contents of the waveform storage circuit are read out using a clock proportional to the sound frequency of a pressed key. For the same note name, the contents of the waveform memory circuit are read out using the readout clock corresponding to the pressed octave, and
By time-divisionally executing the transfer of the waveform data at separate timings during one clock period of the readout clock using a clock that is an integer multiple of the readout clock, the number of waveform data that is an integer multiple of the readout clock is transferred. A waveform data transfer method for electronic musical instruments characterized by transfer within one clock period. 2. The waveform data transfer method for an electronic musical instrument according to claim 1, wherein the clock which is an integral multiple of the readout clock corresponding to the pressed octave is the readout clock of the highest octave of the same note name.