JPS5913755B2 - 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 bass 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 1 is detected by a chord detection circuit 2, and a root tone signal and a chord signal representing the type of chord are outputted 5. For example, when performing automatic bass or automatic arpeggio accompaniment for the five chords of major, minor, seventh, augment, and diminutive, the root tone signal is the root note, 3″ degree, 3rd degree, 5″ degree, 5th degree,
Eight encoders 103 for 6b degrees, 6 degrees, and 7i' degrees,
It is converted into a signal corresponding to each degree. On the other hand, the rhythm pulse generation circuit 4 has a read-only memory (ROM).
) Generates a read pulse and an attack pulse for reading out 5. In the ROM 5, the stored contents are switched according to the type of 15 codes by the code signal from the code detection circuit 2, and a selection signal according to the type of code is outputted by the read pulse from the rhythm pulse generation circuit 4. do. Based on the selection signal from R0M5, selection circuit 6 selects the signals from encoder 3 and sequentially sends them to tone gate 207. For example, if a major is specified by the chord signal, the selection circuit 6 outputs the root note, third,
Signals of 5 degrees, 6 degrees, and 7b degrees are selectively output. The musical tone gate 1 passes the scale signal according to the signal selected by the selection circuit 6, and the amplitude is controlled by the attack pulse from the rhythm pulse generation circuit 4 in the envelope circuit 8 and the filter 9, and the amplifier 10. , the sound is emitted through the speaker 11. In this conventional configuration, ROM 30 and R0M5, which have an increasing number of code types, require storage contents corresponding to the number of code types, making the ROM complex and expensive.

Also, as the number of code types increases, the number of encoders 3 also increases.
As the number of wires increases, the number of bits of the selection circuit 6 also increases, making the configuration considerably more complex. Furthermore, there were drawbacks such as difficulty in octave control when the progression of the bass or arpeggio spanned an octave. C7R - The present invention eliminates the above-mentioned drawbacks of the conventional technology, and its purpose is to provide an automated system with a simple configuration in which the contents of the ROM, the wiring of the integrated circuit, etc. do not change much even if the number of types of codes increases. An object of the present invention is to provide an automatic accompaniment device having a base circuit.

In order to achieve the above object, the movable accompaniment device of the present invention includes a chord detection circuit that detects a root tone signal and a chord signal based on key press information from a keyboard circuit and outputs them in binary numbers, and a counter that stores pitch name information. A memory circuit that sequentially outputs pitch name signals in binary numbers according to the output of the memory circuit, and converts the pitch name signal from the memory circuit into a pitch name signal corresponding to the type of chord using the code signal from the chord detection circuit. An automatic base circuit comprising a note conversion circuit, an addition circuit that adds the output of the note conversion circuit to the root tone signal from the chord detection circuit, and a musical tone conversion circuit that converts the output of the addition circuit into a musical tone. This is a characteristic feature.

The present invention will be described in detail below with reference to examples. FIG. 2 is an explanatory diagram showing the configuration of an embodiment of the present invention, and is a general block diagram of an automatic accompaniment device comprising an automatic bass circuit of the present invention and an automatic arpeggio circuit of similar construction.

In the figure, during normal accompaniment, a chord played on the accompaniment keyboard opens the musical tone gate 23 in response to a key depression signal from the accompaniment keyboard circuit 21, allowing a scale signal corresponding to the key depression to pass through.

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 is passed through the filter 25 and the amplifier 26, and at the same time, the rhythm signal is output to 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 arpeggio 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 generating circuit 59 are reset, so that they operate synchronously. The automatic base circuit of the present invention 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. Various patterns can be obtained by changing the contents of the ROM 32 according to the type of rhythm, such as samba, mambo, ballad, etc., by inputting an automatic bass pattern outputted from the ROM 32 through 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. Even after closing the counter 30, resetting the counter 30, and reading out the bass pattern from the ROM 32, the performance switch SW. Envelope circuit 5 unless b2 is closed
4, no attack signal is given and no musical tone is generated. Now, the note name signal stored in the latch circuit 36 is input to the note conversion circuit 39. Here, the chord signal from the chord detection circuit 22 is converted into a pitch name signal corresponding to the type of chord. 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 chord type is then sent to the chord detection circuit 22 in the addition circuit 41.
is added to the root signal from . 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"010r".The 5-bit note name signal added to the root note signal in the adder circuit 41 is It is converted into a decimal number by a hexadecimal-decimal conversion circuit 43.

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 digit 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 input to a gate 52, respectively.

In the gate 52, the 1/2 frequency division output and the 1/4 frequency division output are selected by the carry signal "o-"11 from the hexadecimal-to-decimal conversion circuit 43, and the output is sent to the envelope circuit 54. Sent. 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 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 otatorve signals are stored in the latch circuit 35 using the attack signal from the ROM 3l 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 automatic base case, 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 similar to the adder circuit 41 in the automatic base circuit. Addition circuit 4
The 5-bit hexadecimal pitch name signal added with the root note at 0 is 16
It is converted into a 5-bit decimal number in the decimal-decimal conversion circuit 42 using the same method as the input/output relationship shown in Table 4 above, and the tone gate 46 derives a corresponding scale signal. The derived scale signal is divided into four types of frequency division ratios 1 in the frequency dividing circuit 49.
The frequency is divided into /2, 1/4, 1/8, and 1/16. On the other hand, the 2-bit octave signal stored in the latch circuit 35 is added to the most significant carry signal from the hexadecimal-decimal conversion circuit 42 in an adder circuit 48, and the signal from the frequency divider circuit 49 is converted into an octave signal in a gate 51. Controlled and selectively derived. The signal passing through the gate 51 is sent to an envelope circuit 53
The amplitude is controlled by the attack signal, and the sound is emitted through the filter 55, amplifier 57, and 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, 29 are divided into a first counter (flip-flops FFlOl to FFlO5) and a second counter (flip-flops FFlO6 to FFllO), and each FFf)Q output of the second counter is used to
Read the contents of M32, 3l 1, and send the 4-bit note name signals 1 to 4 and the attack signal to the output terminal for automatic bass, or the 2-bit note name signals 1 and 2 for automatic arpeggio.
It outputs 2-bit octave signals 1 and 2 and 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 N.
Each D-type FF is inverted via AND circuits 112 and 113.
It is input as a lascivious signal to the C terminals of l2l to 124, and the pitch name signal or octave signal of the D terminal is stored and sent to the next stage note* (conversion circuits 39 and 38.The attack signal is input to the NAND circuit 113. The pattern selection switch terminal selects the type of rhythm, such as rock, waltz, etc.
Specify mambo, swing, ballad, etc. In this case, a priority circuit 117 is provided that determines the priority order when these rhythms are designated simultaneously. The states of terminals CTR (address counter) mode 3, double tempo, and PD (pre-divider) mode 3 of the ROMs 32 and 3l change in accordance with the designated rhythm. For example, if it is a lock, PD mode 3 becomes "1" and the first counter is ternary corrected through the NAND circuit 115, and if it is a swing, the
TR mode 3 becomes "1" and the second counter is corrected in ternary form through the NAND circuit 114, and if it is a waltz, PD mode 3 and CTR mode 3 become "B" and the first and second counters are corrected in ternary form. The double tempo becomes "1" according to the rhythm, and FFLO5 is operated as an inverter. In pattern selection corresponding to each rhythm, the first
Table 6 shows an example of the number of counts for one pattern of the counter and the second counter. As mentioned above, start switch SW. a and performance switch SW. Since it has two control means, start switch SW. a, the rhythm pattern generation circuit, automatic bass circuit, and automatic arpeggio circuit are all operated synchronously, and then the performance switch SW. By using b, it is possible to obtain a musical tone from a desired circuit.

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 inconvenience that the sound changes midway or the sustain is interrupted. Next, a specific example of the note conversion circuit 39 in the automatic bass circuit will be briefly explained.

The logic circuit shown in FIG. 4 converts the 4-bit pitch name signal stored in the latch circuit 36 into a pitch name signal corresponding to the code signal from the chord detection circuit 22.

If the code signal is “000” (major) or “010” (
7th), the pitch name signal from the latch circuit 36 is directly input to the adder circuit 41. Also, when it is “001” (minor), the note conversion circuit 39 outputs “゛゜0100” (E).
When input, the note is converted to ``001 pi (D#), and other notes are converted according to Table 2.In this way,
For example, for samba and ballad rhythms, examples of bass patterns shown in FIGS. 5A and 5B are obtained depending on the type of chord.

The note-converted pitch name signal is applied to the musical tone gate 47 via the addition circuit 41 and the hexadecimal-decimal conversion circuit 43, as in the case of the arpeggio, and a corresponding scale signal is derived. As explained above, according to the automatic bass circuit of the present invention, the memory circuit (ROM) stores note name information regarding one type of chord, while the chord detection circuit detects the chord signal from key press information. The note conversion circuit generates pitch name signals for various chords by converting the pitch name signal from the memory circuit into a pitch name signal corresponding to the chord type using the code signal from the chord detection circuit. can do.

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 note conversion circuits need only be changed slightly, simplifying the configuration and integrating the circuit. becomes easier. This also applies to the automatic arpeggio circuit proposed separately as explained in the embodiment, and there is also the advantage that it can be created using a common system when integrated circuits are used. Further, since a method is used in which a 4-bit pitch name signal and a 4-bit root note signal are added by an adder, octave control can be easily performed using a carry signal generated by the addition.

[Brief explanation of drawings]

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, FIGS. 3 and 4 are detailed explanatory diagrams of main parts of the embodiment of FIG. Figures A and b are explanatory diagrams of performance effects according to the present invention, in which 21 is an accompaniment keyboard circuit, 22 is a chord detection circuit, 23 is a tone gate, 24 is a gate, 25
is a filter, 26 is an amplifier, 27 is a differential circuit, 28 is a clock generator, 29 and 30 are counters, 31 and 32 are memory circuits (ROM), 33 and 34 are gates, 35 and 36 are latch circuits, and 37 is a code Conversion circuits, 38 and 39 are note conversion circuits, 40 and 41 are addition circuits, and 42 and 43 are 16
decimal-decimal conversion circuit, 46, 47 are musical tone gates, 48 is an addition circuit, 49, 50 are frequency dividing circuits, 51, 52 are gates, 53, 54 are envelope circuits, 55, 56 are filters, 57, 58, 61 is an amplifier, 59 is a rhythm pattern generation circuit, 60 is a rhythm sound source, and 62 and 63 are speakers.

Claims (1)

[Claims] 1. A chord detection circuit that detects root note signals and chord signals based on key press information from the keyboard circuit and outputs them in binary numbers.It stores note name information and sequentially outputs note name signals in binary numbers according to the output of the counter. a memory circuit for converting the note name signal from the memory circuit into a note name signal according to the type of chord using the code signal from the chord detection circuit; An automatic accompaniment device characterized by comprising an automatic bass circuit comprising an addition circuit that adds a root tone signal from the circuit, and a musical tone conversion circuit that converts the output of the addition circuit into a musical tone.