JPS61134798A - Musical sound signal generator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a musical tone signal generation device that reads waveform sample data from a waveform memory. ), and the sampling clock pulse for waveform readout is thinned out or packed in accordance with the pitch difference, thereby making it possible to generate musical tones with rich timbre variations with a small memory capacity.

[Conventional technology]

Conventionally, waveform sample data for multiple cycles (typically from attack to decay 1) of a musical tone signal to be generated is stored in a waveform memory, and the waveform sample data is read from this waveform memory. Techniques for generating musical tone signals exhibiting complex timbre changes similar to sounds are known (see, for example, Japanese Patent Laid-Open No. 123313/1983).

[Problem that the invention seeks to solve]

When applying this technology to construct a keyboard-type electronic musical instrument, the waveform memory contains waveform sample data for l notes. A possible method is to store the information and read it out at different rates for each key. However, in this method, one stored waveform is shared by all keys, so if you want to have a slightly different timbre for each key, such as the sound of a natural instrument, for example, you can use a fixed formant key, such as a human voice. It is not suitable for cases where you want to In other words, in these cases, it is preferable to memorize and read out the musical sound waveform corresponding to each key. When storing waveform sample data up to The number of bits (capacity) of is expressed as fQXk. Assuming that a musical sound such as a scat chorus is generated by storing the leaf waveform for each key as described above, and if the number of keys is '%'n, then the memory capacity will be:
foXkXn, which requires a large memory capacity Z.

In this case, if the sampling rate is increased to increase the resolution of the musical sound waveform, the memory capacity will become even larger.

In this way, with the method of storing musical waveforms for each key,
While this has the advantage of allowing each sound to have a different timbre or have a fixed formant characteristic, it also has the disadvantage of requiring an enormous amount of memory, making the readout circuit more complicated and increasing costs.

[Means for solving problems]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned disadvantages while maintaining the above-mentioned advantages of the method of storing tone waveforms for each key.

Achievement of 2″′1 - t, b y, = ao・20 shots 1
0 Musical tone signal 1 generation device includes (a1) a waveform memory storing waveform sample data for multiple frequencies regarding the musical tone signal to be generated, and (bl) pitch specification for selectively specifying a plurality of mutually different pitches. and le) When a certain pitch is specified by this pitch specifying means and when the pitch of sen is specified, Vrusu is thinned out or packed in response to the difference in pitch. pulse generating means for generating sampling clock pulses with different numbers of pulses per fixed time; and reading means for reading out the waveform sample data from the waveform memory in response to the sampling clock pulses from the pulse generating means. It is something that has been prepared.

[Effect]

According to the structure of the invention, the waveform sample data for one note is shared by multiple pitches (multiple keys), so even if there are multiple keys, the waveform memory can store the musical waveforms for all keys. This is not necessary; it is sufficient to memorize musical sound waveforms for every several consecutive keys, and the memory capacity is less than half that of storing all keys.

Therefore, the configuration of the readout circuit can be simplified, and costs can be reduced.

Furthermore, if musical sound waveforms are stored for each of several keys, the timbre and formant can be made different for each of the several tones corresponding to those several keys.

Furthermore, pitch changes are achieved by thinning out or packing the sampling clock pulses and changing the number of pulses per certain period of time, so even for several keys that share one musical waveform, each The shape of the readout waveform is slightly different for each key, and as a result, it is possible to create slightly different tones for each note, or to achieve fixed formant characteristics.

〔Example〕

FIG. 1 shows an embodiment in which this invention is applied to a Chemiko musical instrument, and the electronic musical instrument of this embodiment is an ADM
(Adaptive delta pitch) system is used to record and reproduce musical sound waveforms corresponding to musical tones of each pitch, and the pitch of the reproduced musical tones can be specified using the keyboard.

The keyboard circuit 10 includes a keyboard having a large number of keys, and a key switch is provided corresponding to each key.

The key press detection port W&12 detects a pressed key by sequentially and repeatedly scanning the many key switches 7 in the keyboard circuit 10, and when a key is pressed on the keyboard, the key is Corresponding key code data KC and key-on signal KONg are sent out. Furthermore, when a plurality of keys are pressed at the same time, the priority key selection function sends out only the key code data KC corresponding to a predetermined priority key (for example, the highest key).

The waveform memory 14 has one waveform memory for every three consecutive keys (for example, C-C#-D, D#-E-F...).
If the number of keys on the aforementioned keyboard is, for example, 49, then
Waveform sample data for 17 tones is stored. In the case of case B, the waveform sample data for each of the three keys is stored as ADM by sampling the musical sound waveform corresponding to the highest note of the three keys from attack to decay at a sampling frequency of 20 (KHz). This is bit-serial data encoded using a method.

The waveform selection signal generation circuit 16 generates a waveform selection signal WS for selecting a waveform to be read in response to the key code data KC from the key press detection circuit 12. In the waveform memory 14, a waveform to be successively displayed is selected in response to a waveform selection signal WS each time a key-on operation is performed on the keyboard. In this case, for the three keys that share one musical tone waveform, regardless of which key is turned on, that one musical tone waveform is designated to be read out.

By the way, the circuit for supplying the address signal AWE for waveform reading to the waveform memory 14 includes a master clock source 18, a sampling clock generation problem, a gate circuit η, an address counter 24, a frequency division number memo I726 .
t″i″
'・1 Master clock pulse MP generated from master clock source 18
is converted into a sampling clock pulse SP having a frequency of, for example, 2 (1 (KHz)) by being divided by the sampling clock generation problem.Here, the frequency of the sampling clock pulse SP is determined by the waveform memory 14.
All of the tone waveforms stored in the memory may be the same, or they may be changed depending on the frequency band of the tone to be generated. To do this, input the clock generator 'XJK waveform selection signal WS (t or key code data KC')' and control the frequency 7 of the sampling clock pulse SP according to the signal Ws. good.

The sampling clock pulse SP sent out from the sampling clock generator is supplied to the gate circuit @ρ on the one hand, and to the variable frequency divider on the other hand. The variable frequency divider side is for dividing the frequency of the sampling clock pulse SP according to the frequency division number data DN from the frequency division number memory 26, and the frequency division output pulse DP is transmitted through 30 inputs. The gate circuit 22 is non-conducting: iF4 is set to control the gate circuit 22. However, unless the divided output pulse DP is generated, the gate circuit ρ receives the output "1" of the inverter I as the enable signal IN and becomes conductive. 2.

As shown in FIG. 2 (al), the frequency division number memory 26 stores 1 (
9) /-rahe pulse P・a
In order to make it possible to thin out the frequency division number data of the three persimmons, the frequency division number data to be read out is specified by the key code data KC from the key press detection circuit 12. It has become. Here, among the frequency division number data of the three keyaki classes, the inhibition of the frequency division operation of the first class (σ) is expressed, the second division number is 16, and the third persimmon class is The one represents the frequency division number 8. Then, the frequency division number data for the first persimmon type is read out for each of the aforementioned three consecutive keys in accordance with the key code data KC representing the Sakae high note key, and the frequency division number data for the second type is read out for the highest note key. The third type of frequency division number data is read out in accordance with the key code data KC representing a key one semitone lower than the highest pitch key. In addition,
Although the frequency division number data of the first buildings does not represent the frequency division number, it is referred to as frequency division number data for convenience.

When the variable frequency divider 28t/'i sends out the frequency division number data DN of the first m class from the frequency division number memory %, the frequency division operation is not performed, and therefore the frequency division output pulse DPg is not transmitted. Therefore, the gate circuit Wr22 continues to be in a conductive state,
The sampling clock pulse SP is directly supplied to each address counter as the output pulse sP' of the OG gate circuit 22.

Also, the frequency division number data D of the second scale is stored from the frequency division number memory 26.
When N is sent out, the variable frequency division circuit divides the frequency of the sampling clock pulse SP by 1/16 and sends out one pulse every 16 pulses as a divided output pulse DP. For this reason,
In the gate circuit ρ, the sampling clock pulse SP is thinned out by one pulse every 16 pulses, and this thinning-out process (the requested pulse train is the gate)! "il approximately ρ output pulse S
P' and then supplied to the address counter 2A.

Furthermore, when the frequency division number data DN of the third building type is sent out from the frequency division number memo IJ 26, the variable frequency division route divides the sampling clock pulse 5py1/s, and divides the frequency of the sampling clock pulse 5py1/s to 8 pulses f.
5Kl/''Ruswo frequency division output is sent as Hals DP.

Therefore, in the gate circuit ρ, the sampling clock pulse SP is thinned out by 1 pulse every 8 pulses, and the pulse train subjected to this thinning control is the output pulse SP of the gate circuit η.
′ is supplied for each address counter. In addition,
The variable frequency division circuit may be one that divides the master clock pulse MPY as shown by the broken line A, or it may be initialized according to the key-on signal KON as shown by the broken line B. good.

The address counter outputs the key-on signal KONy! from the key press detection circuit 12. Each time the signal KON is received, a reset is performed at the rising edge of the signal KON, and after the reset, the output pulse SP' from the gate circuit V16ρ is counted and the address signal AW for reading the waveform is generated. and supplies it to the waveform memory 4. Therefore, the musical sound waveform designated by the waveform selection signal WS is read out from the waveform memory 4 in accordance with the address signal AW, and bit-serial waveform sample data SWD representing the musical sound waveform is sent out as an approximate readout output. .

Here, the reason why pitch change can be achieved by the above-mentioned pulse thinning control will be explained. In the above example, the waveform sample data representing the musical sound waveform corresponding to the highest key for every three consecutive keys was stored in the waveform memory 14.
If k O,2[see ], the number of bits of the stored data corresponding to the highest key can be 4096. For convenience of explanation, PJ treble key 7 is designated as “D”.
The keys that are a semitone and one lower than that are "C town" and ", respectively.
C'', when key D is turned on, the output pulse SP' (sampling clock pulse S
4096 bits of stored data are read out in response to the key D (P itself), and the pitch corresponding to the key D is obtained.

Next, assuming that key C# is turned on, the gate circuit ρ outputs the output pulse SP' by thinning out one pulse every 416 pulses of the sampling clock pulse SP'.
In response, 4096 bits of stored data are read out. In this case, the address counter cannot count 1 pulse every 16 pulses, so 4
To read 096 bits of stored data, 4096
+256 The same time y as when reading the bit data
al-It will take. Therefore, a pitch approximately lower than key D can be obtained.

Furthermore, when key C is turned on, the gate circuit ρ sends out the sampling clock pulse SP, which is thinned out by one pulse every 8 pulses, as an output pulse SP', and accordingly the 4096-bit memory is One more piece of data will be output. In this case, the address counter can only count 1 pulse every 8 pulses, so 409
To read 6 bits of stored data, 4096
It takes the same time as reading 4512 bits of data. Therefore, using the same formula as above, 2
04 cents and a pitch approximately I lower than the key D.

Waveform memo Waveform sample data 8W sent from January 4th
D is supplied to the decoding circuit 32. The decoding circuit 32 outputs a key-on signal KON)? The decoding operation starts every time the waveform sample data is received, and is decoded in synchronization with the output pulse SP' of the arithmetic gate circuit ρ using the 8WDyADM method.
Reproduction waveform data R1) representing a reproduction waveform is sent out.

The reproduced waveform data Rr) is digital/analog (D/
A) It is converted into an analog signal by the conversion circuit 34 and supplied to the sound system. Therefore, the sound system Akara generates musical tones corresponding to the keys that are turned on.

In the above embodiment, the sampling clock pulses 7822 are thinned out, but one pulse Pb may be packed every several pulses as shown in FIG. 2 (bl).

The storage method of the waveform memory is not limited to the ADM method.
PCM (Pulse Code Modulation), DPCM (Differential Pulse Code Modulation), ADPCM (Adaptive Differential Pulse Code Modulation)
, DM (delta modulation), or the like may be used.

〔Effect of the invention〕

As described above, according to the present invention, the waveform sample data for one tone stored in the waveform memory is shared by the slope key, and is thinned out or packed in accordance with the pitch difference of the sampling clock pulsen for waveform reading. This makes it possible to significantly reduce the memory capacity, and has the effect of simplifying the circuit configuration and reducing costs. Also, similar to the case where musical sound waveforms are stored for each key, musical tone signals with slightly different tones for each note and musical tone signals with fixed formant characteristics! There are also benefits that can occur.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention applied to an electronic musical instrument, and Fig. 2 (at and (bl) are waveform diagrams showing thinning and packing of sampling clock pulses. 14... Waveform memory, 16...Waveform selection signal generation circuit, 18...Mask clock source, Addition...Sampling clock generator, ρ...Gate circuit,
...address counter, %...dividing number memory, public...variable frequency divider, 30...in/cutau

Claims (1)

[Scope of Claims] (a) A waveform memory that stores waveform sample data for a plurality of periods regarding a musical tone signal to be generated, and (b) a pitch specifying means for selectively specifying a plurality of mutually different pitches. (c) When a certain pitch is specified by this pitch specifying means and when another pitch is specified, pulses are thinned out or packed in accordance with the difference in pitch, so that a certain period of time is pulse generating means for generating sampling clock pulses with different numbers of pulses per pulse, and (d) reading means for reading out the waveform sample data from the waveform memory in response to the sampling clock pulses from the pulse generating means. musical tone signal generator.