JPS5913756B2 - automatic accompaniment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic accompaniment device that has a simple configuration as an automatic arpeggio circuit for multiple chords and is suitable for integration into an integrated circuit.

The circuit configuration of a conventional automatic bass or automatic arpeggio is shown in FIG.

In the figure, a chord played on an accompaniment keyboard 15 is detected by a chord detection circuit 2, and a root tone signal and a chord signal representing the type of chord are output. For example, you can perform automatic bass or automatic arpeggio accompaniment for five types of chords: major, minor, seventh, augment, and diminutive chords.
, the root signal is the root, 31' degrees, 3 degrees, 5 degrees, 5
Eight encoders 3 for degrees, 6 degrees, 6 degrees, and 7'' degrees convert the signals into signals corresponding to the respective degrees.On the other hand, the rhythm pulse generation circuit 4 outputs signals from a read-only memory (ROM).
A read pulse 15 and an attack pulse for reading 5 are generated. In R0M5, the stored contents are switched according to the type of chord by the code signal from the chord detection circuit 2, and the selection signal according to the type of chord is outputted by the read pulse from the rhythm pulse generation circuit 4. . Based on the selection signal from the 20ROM 5, the selection circuit 6 selects the signals from the encoder 3 and sequentially sends them to the tone gates T.

For example, if a major is specified by the chord signal, the selection circuit 6 outputs the root note, 3rd, 5th, 6th, and 7th.
The signal of degree b is selectively outputted. The musical tone gate 7 passes the scale signal using the signal selected by the selection circuit 6, and the amplitude is controlled by the envelope circuit 8 using the attack pulse from the rhythm pulse generation circuit 4. Furthermore, a filter 9, an amplifier 10, Thirty sounds are emitted through the speaker 11. In this conventional configuration, as the number of types of codes increases, the ROM 5 needs to have the same number of storage contents as the number of code types, making the ROM complex and expensive.

Furthermore, as the number of types of codes increases, the number of encoders 3 increases by 35, and the number of wires increases accordingly, as well as the number of bits of the selection circuit 6, making the configuration quite complex. Furthermore, the bass or ``Ω'' had drawbacks such as difficulty in octave control when the arpeggio progression spanned an octave.

The present invention aims to eliminate the above-mentioned drawbacks of the conventional art, and its purpose is to create an automatic arpeggio circuit with a simple configuration in which the contents of the ROM and the wiring of the integrated circuit do not change much even if the types of chords increase. An object of the present invention is to provide an automatic accompaniment device having the following features. In order to achieve the above object, the automatic accompaniment device of the present invention includes a chord detection circuit that detects root tone signals and chord signals based on key press information from a keyboard circuit and outputs them in binary numbers, and a chord detection circuit that stores note names and octave information. A memory circuit that sequentially outputs a pitch name signal and an octave signal according to the output of a counter, and converts the pitch name signal from the memory circuit into a pitch name signal according to the type of chord using the chord signal from the chord detection circuit. a note conversion circuit for adding the output of the note conversion circuit with the root note signal from the chord detection circuit; The present invention is characterized in that it comprises an automatic arpeggio circuit comprising means for frequency division control and a musical tone converting circuit for converting the output of the means into musical tones.

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

FIG. 2 is an explanatory diagram showing the structure of an embodiment of the present invention, and shows an overall block diagram of an automatic accompaniment device comprising an automatic arpeggio circuit of the present invention and an automatic bass circuit of similar construction.

In the figure, in normal accompaniment, a tone played on the accompaniment keyboard opens the musical tone gate 23 in response to a key press signal from the accompaniment keyboard circuit 21, and allows a scale signal corresponding to the key press to pass.

The scale signal that has passed through the musical tone gate 23 is carved into a rhythm by the rhythm pulse from the rhythm pattern generation circuit 59 at the gate 24 and passed through the filter 25 and amplifier 26, and at the same time, the rhythm signal is generated by the rhythm pattern generation circuit 59.
from the rhythm sound source 60 and the speaker 62 via the amplifier 61.
More sound is emitted. On the other hand, the key press signal is sent to the code detection circuit 22.
It detects the root note and chord type and sends it to the automatic bass circuit and automatic albeggio circuit. In these circuits, the starting switch SW. By closing a, a set signal is output from the differentiating circuit 27, and the counters 29 and 30 driven by the clock generator 28 and the rhythm pattern generation circuit 59 are reset, so that they operate synchronously. . First, the automatic base circuit reads the contents of the ROM 32 based on the output of the counter 30.

The ROM 32 stores an automatic bass pattern corresponding to the C major chord, and outputs a pitch name signal in binary numbers according to the pattern. Table 1 shows these pitch name signals in 4-bit binary numbers. The automatic bass pattern output from the ROM 32 can be changed to various patterns by changing the contents of the ROM 32 according to the type of rhythm, such as samba, mambo, ballad, etc., by inputting a pattern selection switch (not shown). .

This pitch name signal is stored in the latch circuit 36 using the attack signal from the ROM 32 as a latch pulse. This attack signal is applied to a latch circuit 36 and an envelope circuit 54 via a gate circuit 34. In this case, the gate circuit 34 is connected to the performance switch SW. This allows the attack signal to pass when b2 is closed. That is, starting switch SW. Close a, reset the counter 30, and return to RO.
Even if the bass pattern is read from M32, the performance switch SW. Unless b2 is closed, no attack signal is applied to the envelope circuit 54 and no musical tone is generated. Now, the note name signal stored in the latch circuit 36 is transferred to the note conversion circuit 39.
Enter. Here, the code signal from the code detection circuit 22 is converted into each sound signal according to the type of code. Table 2 shows how notes are converted depending on the type of chord, typically for a bass progression in a swing rhythm. The pitch name signal corresponding to the type of chord is then added to the root tone signal from the chord detection circuit 22 in an adding circuit 41. The root signal is also output as a 4-bit binary number as shown in Table 1. Table 3 shows, as an example, the relationship between the input and output of the adder 41 when the root note is F"0101".The 5-bit note name signal added to the root note signal in the adder circuit 41 is Hexadecimal-decimal conversion circuit 4
3 converts to decimal.

Table 4 shows the input/output relationship of this hexadecimal-decimal conversion circuit. The most significant of the 5 bits is carried up by the numerical value 13, and this carry signal is sent to the gate 52, and the lower 4 bits are sent to the tone gate 47.

A tone gate 47 derives a scale signal corresponding to the lower 4 bits of the output from Table 4.

The derived scale signal is frequency-divided by 1/2 and 1/4 in a frequency dividing circuit 50, and inputted to a gate 52, respectively.

At the gate 52, the above-mentioned carry signal from the hexadecimal-decimal conversion circuit 43 is converted to 1/2 by "0-"11.
The frequency-divided output and the 1/4 frequency-divided output are selected and sent to the envelope circuit 54. The envelope circuit 54 controls the amplitude of the scale signal using the aforementioned attack signal. Thereafter, the sound is emitted through a filter 56, an amplifier 58, and a speaker 63. Next, the automatic arpeggio circuit which is the main part of the present invention will be explained.

Similarly to the automatic base circuit, R is determined by the output of the counter 29.
Read OM3l. The ROM 3l stores an arpeggio pattern corresponding to the C major chord, and outputs a pitch name signal in a 2-bit binary number and an octave signal in a 2-bit binary number. In the case of an arpeggio, four types of note name signals can be output using 2 bits, but this is because an arpeggio usually consists of only three or four notes that make up a chord. And since the arpeggio spans several octaves, 4
A seed octave signal is prepared. It is also possible to obtain various arpeggio patterns by changing the contents of the ROM 3l using a pattern selection switch that changes the pattern according to rhythms such as mambo, swing, march, etc. These pitch name signals and octave signals are stored in the latch circuit 35 using the attack signal from the ROM 31 as a latch pulse. Here, the gate circuit 33
is the performance switch SW. This allows the attack signal to pass when the bl is closed. That is, as in the case of the automatic base, the start switch Sw. Even if you close A, reset the counter 29, and read out the note name signal and octave signal of the arpeggio pattern from the ROM 3l, the performance switch S
W. Unless bl is closed, no attack signal is given to the envelope circuit 53, and no arpeggio sound is generated. Now, the 2-bit pitch name signal stored in the latch circuit 35 is input to the code conversion circuit 37, and the 4-bit C. E. G3
It is converted into a species pitch name signal. Further, this pitch name signal is converted by the note conversion circuit 38 into a pitch name signal corresponding to the chord type of the chord signal from the chord detection circuit 22. Table 5 shows an example in which a 2-bit pitch name signal is converted into a 4-bit pitch name signal depending on the type of chord. The pitch name signal thus converted into 4 bits is then added to the root note signal from the chord detection circuit 22 in the addition circuit 40.

This adder circuit 40 is the adder circuit 4 in the automatic base circuit.
It is the same as 1. The 5-bit hexadecimal pitch name signal added to the root note in the adder circuit 40 is converted into a 5-bit hexadecimal number in the hexadecimal-decimal conversion circuit 42 using the same method as the input/output relationship in Table 4 above. The musical tone gate 46 derives a corresponding scale signal. The derived scale signal is divided into four types of frequency division ratios 1/2, 1/4, 1/8, and 1 in the frequency dividing circuit 49.
The frequency is divided into /16. On the other hand, the 2-bit octave signal stored in the latch circuit 35 is converted to hexadecimal -1 by the adder circuit 48.
It is added to the most significant carry signal from the binary converter circuit 42, and the signal from the frequency divider circuit 49 is subjected to octave control at the gate 51 and selectively derived. The signal that has passed through the gate 51 is amplitude-controlled by an attack signal in an envelope circuit 53, and is emitted through a filter 55, an amplifier 57, and a speaker 62. Next, a detailed view of the main parts of the embodiment shown in FIG. 2 will be explained.

FIG. 3 shows a specific circuit from the clock generator 28 in FIG. 2 to the latch circuit 36 in the automatic bass circuit and to the latch circuit 35 in the automatic arpeggio circuit, and these circuits are common to both.

Start switch SW. When a is closed, the delay circuit 116 and NA
A trigger pulse is generated by the ND circuit 111 and counters 30 and 29 are reset. The counters 30 and 29 are the first counters (flipflops FFlOl to FFlO
5) and the second counter (flip-flop FFlO6~
Q of each FF of the second counter
The contents of the ROMs 32 and 3l are read out by the outputs C1 to C5, and the 4-bit note name signals 1 to 4 and the attack signal are sent to the output terminals in the case of automatic bass, and the 2-bit note name signals 1 and 2 in the case of automatic arpeggio. 2-bit octave signal 1,
2 and outputs an attack signal. The pitch name signals 1 to 4 or the pitch name signals 1 and 2 and the octave signals 1 and 2 are input to each D terminal of the latch circuits 36 and 35, that is, the D type FF121 to 124, and the performance switch SW. If b is closed,
The attack signal is inverted via the NAND circuits 112 and 113 and input as a latch signal to the C terminal of each D-type FFl2l to 124, and the pitch name signal or octave signal of the D terminal is stored and the note of the next stage is changed. Switching circuit 39, 3
Sent to 8th. Also, the attack signal is the NAND circuit 113
The signal is sent to envelope circuits 54 and 53 through. The pattern selection switch terminal specifies the type of rhythm, such as rock, waltz, mambo, swing, ballad, etc. In this case, a priority circuit 117 is provided that determines the priority order when these rhythms are designated simultaneously. Terminal CT of ROM32, 3l according to the specified rhythm.
R (address counter) mode 3, double tempo, PD
(Pre-divider) The state of mode 3 changes. For example, if it is a lock, PD mode 3 becomes "1" and the first counter is corrected in ternary form through the NAND circuit 115, and if it is a swing, CTR mode 3 becomes "1" and the second counter is corrected in ternary form through the NAND circuit 114. , in the case of a waltz, PD mode 3 and CTR mode 3 become "1", and the first and second counters are corrected in ternary form.

Furthermore, the double tempo changes to “1” according to the rhythm, and F
FlO5 is operated as an inverter. Table 6 shows an example of the count numbers of one pattern of the first counter and the second counter in pattern selection corresponding to each rhythm. As mentioned above, starting switch SW. a and the performance switch. SW. Since it has two control means, start switch SW. a rhythm pattern generation circuit;
The automatic bass circuit and the automatic arpeggio circuit are all operated synchronously, and then the musical tone from the desired circuit can be obtained by operating the performance switches S7 and b.

Furthermore, since latch circuits 36 and 35 are provided at the outputs of the ROMs 32 and 3l, even when a new rhythm is selected or automatic performance is stopped, there is no problem that the sound changes midway or the sustain is interrupted. FIG. 4 shows a specific circuit from the code conversion circuit 37 to the envelope circuit 53 in the automatic arpeggio circuit.

The 2-bit note name signal stored in the latch circuit 35 is inputted, for example, to a code conversion circuit 37 made up of logic circuits 209 to 214 shown, and a note conversion circuit 38 made up of logic circuits 201 to 208, and also to a chord detection circuit 22. The note conversion circuit 38 converts the 3-bit code signal shown in Table 7 below.
The 2-bit pitch name signal is converted into a 4-bit pitch name signal corresponding to the chord types shown in Table 5 using the 3-bit code signal. Then, the addition circuit 40 adds the root note signal from the chord detection circuit 22, and the resulting 5-bit hexadecimal note name signal is added to the 1st note signal of the next logic circuit.
In the hexadecimal-to-decimal conversion circuit 42 shown in the example, 12
After being converted into a binary number, the musical tone gate 46 is controlled. Now, for example, the latch circuit 35 outputs "00゛," as a pitch name signal.
01-"10" are input in sequence, a measure "000" is input as a chord signal from the chord detection circuit 22, and a root tone signal from the chord detection circuit 22 is input as "00".
When setting it to 00゜゛ (pitch name C), the operation is as follows. Since the code signal is "゜000゛", AND circuit 2
The output of 01 is "1", but the AND circuits 202 and 20
The output of 3, . . . , 208 becomes “0”. Therefore, when the pitch name signal is "00", the input of the adder 40 is 0.
The outputs of the R circuits 211, 212 and the AND circuits 213, 214 are all "0", and the AND circuit 20 of the carrier input
The output of the adder 40 is also ゜゜0゛, and the input of the adder 40 is "000".
01 (pitch name C). Next, when the pitch name signal is "01", the outputs of the 0R circuits 211 and 212 are "11", and the output of the AND circuit 209 of the carry input is "1", so the input of the adder 40 is "001F". ``11 is added and ``0
1001 (pitch name E). Furthermore, the pitch name signal is “10”
When , the outputs of the AND circuit 213 and the 0R circuit 212 are “1”.
'', and the output of the AND circuit 209 of the carry input also becomes 1, so the input of the adder 40 becomes ``1'' at ``0110''''.
The result of adding 5 is "011F" (pitch name G). The above corresponds to the major "0000" in Table 7, but other chord minors, sevenths, diminuts, augmentations, (errors), etc. The aforementioned AND circuits 201 to 208 are set to predetermined logic outputs according to the code signal, and in combination with the pitch name signal, the fifth
As shown in the table, a 2-bit pitch name signal is converted into a 4-bit pitch name signal depending on the type of chord.

The 4-bit note name signal converted according to the chord type as described above is added to the 4-bit root note signal from the chord detection circuit 22, and is converted into a 5-bit hexadecimal note name signal.
It is sent to the hexadecimal-decimal conversion circuit 42, and converted into a decimal number by a logic circuit whose circuit is based on the principles in Table 4.
The musical tone gate 46 is controlled by the lower 4 bits of the bit output,
The scale signal C-B from the sound source corresponding to the pitch name signal is selected and output to nines 1-4.

On the other hand, the most significant carry signal of the 5-bit output of the hexadecimal-decimal conversion circuit 42 is sent to an adder circuit 48 and added to the octave signal. That is, the 2-bit octave signal stored in the latch circuit 35 is sequentially added through a parallel circuit consisting of an exclusive 0R circuit and an AND circuit, and the gate 51 is controlled by the output thereof. Line l- from the aforementioned musical tone gate 46
The scale signal outputted through the adder circuit 48 is input to a frequency divider circuit 49, where the frequency is divided into four stages corresponding to the octave, and the output of each stage is selectively derived in the gate circuit 51 according to the output of the adder circuit 48. The selected scale signal is sent to the envelope circuit 5.
3, and the amplitude is controlled by the attack signal from ROM 3l, and the scale signal of the envelope waveform is passed to the filter 5.
5. As explained above, according to the automatic arpeggio circuit of the present invention, the memory circuit (ROM) stores note name information regarding one type of chord, while the chord detection circuit detects a chord signal from key press information. The note name signal from the storage circuit is converted into a note name signal according to the type of chord in a note conversion circuit using the chord signal from the chord detection circuit, and the signal is added to the root note signal from the chord detection circuit. Then, a scale signal is selectively derived from the addition output, and frequency division control is performed using the octave signal from the storage circuit.

In this way, various chords spanning several octaves can be easily obtained.

In this case, even if the number of code types increases, the content of the ROM as well as the number of wires can be kept almost constant, and external circuits such as the note converter circuit can be slightly changed. This makes it easier to The same can be said of the automatic bass circuit proposed separately as explained in the example, and in the case of integrated circuits, both can be integrated into a common system, that is, the output of the ROM is converted into a 2-bit pitch name signal and a 2-bit octave signal. This is a total of 4-bit binary numbers, and can be manufactured using a common system by simply changing the mask by combining the 4-bit binary numbers of the automatic base circuit and the output terminal, which is an extremely advantageous condition for production. In addition, since the 2-bit pitch name signal is converted to 4-bits using a note conversion circuit and the 4-bit pitch name signal is added to the 4-bit root note signal, the octave is controlled by the carry signal generated by the addition. can be easily performed, and addition of this and the original octave signal can also be performed with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional example, FIG. 2 is an explanatory diagram showing the configuration of an embodiment of the present invention, and FIGS. 3 and 4 are detailed explanatory diagrams of main parts of the embodiment of FIG. In the figure, 21 is an accompaniment keyboard circuit, 2
2 is a chord detection circuit, 23 is a musical tone gate, 24 is a gate, 25 is a filter, 26 is an amplifier, 27 is a differentiation circuit, 2
8 is a clock generator, 29, 30 are counters, 31, 3
2 is a memory circuit (ROM), 33, 34 are gates, 35,
36 is a latch circuit, 37 is a code conversion circuit, 38, 39
is a note conversion circuit, 40, 41 is an addition circuit, 42, 43
is a hexadecimal-decimal conversion circuit, 46 and 47 are musical tone gates,
48 is an adder circuit, 49, 50 is a frequency divider circuit, 51, 52 are gates, 53, 54 are envelope circuits, 55, 56 are filters, 57, 58, 61 are amplifiers, 59 is a rhythm pattern generation circuit, 60 is a rhythm Sound sources 62 and 63 indicate speakers.

Claims (1)

[Claims] 1. A chord detection circuit that detects the root note signal and chord signal based on the key press information from the keyboard circuit and outputs it in binary numbers. It stores the note name and octave information and outputs the note name signal and octave signal according to the output of the counter. A memory circuit that sequentially outputs
A note conversion circuit converts the note name signal from the storage circuit into a note name signal according to the type of chord using the code signal from the chord detection circuit; an adder circuit for adding the sound signal; means for selectively deriving a scale signal based on the output of the adder circuit; and controlling frequency division using an octave signal from the storage circuit;
and an automatic arpeggio circuit comprising a musical tone conversion circuit for converting the output of the means into a musical tone.