JPS5942879B2 - automatic accompaniment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic accompaniment device that can produce a plurality of predetermined accompaniment tones by pressing just one key on an accompaniment keyboard.

Traditionally, when playing accompaniment, major chords are 1st, 3rd,
For fifths and sevenths, complete accompaniment notes could not be obtained unless three or four keys were pressed, such as the first, third, fifth, and minor seventh.

There are also models that allow accompaniment with one key, but due to the circuit configuration, it is usually best to specify two types of chords, such as major and minor.

Furthermore, conventional automatic accompaniment devices have a large number of individual parts and wiring, which is inconvenient for large-scale integrated circuits (LSI), so a circuit configuration suitable for this is desired.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic accompaniment device having a circuit configuration that can be easily integrated into an LSI and which can produce a plurality of predetermined accompaniment tones by pressing only one key on an accompaniment keyboard.

In order to achieve the above object, the automatic accompaniment device of the present invention includes a root note detection circuit that outputs a root note signal when one key is pressed on an accompaniment keyboard, a counter that operates with a clock from a clock generator, and an output signal of the counter. A matching gate that selects and derives the output according to a set chord signal, a selection circuit that selects the output of the matching gate based on a signal from a separately provided chord specifying means, and when the output of the selection circuit matches the set chord, A memory circuit that reads and stores the output of the counter;
The present invention is characterized by comprising an adder that adds the output of the root note detection circuit and the output of the storage circuit, and a musical tone signal conversion circuit that converts the output of the adder into a musical tone signal. The present invention will be described in detail below with reference to examples.

FIG. 1 is an overall explanatory diagram showing the configuration of an embodiment of the accompaniment device of the present invention.

In the figure, the lower keyboard is used as an accompaniment keyboard and includes a chord generation circuit, which is the main part of the present invention. That is, for normal accompaniment on the lower keyboard, the opening/closing circuit 2 is operated by turning the lower keyboard key switch 4 on and off, allowing the sound from the sound source 1 to pass through and output through the gate 3, filter 9, and amplifier 10. Next, when performing automatic accompaniment, the root note detection circuit 5 detects the root note signal by pressing one key of the lower keyboard key switch 4,
One of the signals is sent to the automatic bass accompaniment circuit 11 to generate a bass sound, and the other is sent to the chord generation circuit according to the present invention. The chord generation circuit 6 generates a chord signal using the root note signal and an external chord designation signal that specifies the type of chord, and a sound corresponding to the chord signal is guided from the sound source 1. The musical tone signal outputted from the chord generation circuit 6 is outputted through a gate 7 controlled by pulses from a rhythm pulse generator 8. FIG. 2 is a detailed explanatory diagram of the code generation circuit 6 of FIG. 1 and its related parts.

In the figure, the lower keyboard is used as an accompaniment keyboard, and when one key of the key switch circuit 21 (corresponding to 4 in Figure 1) is pressed, the root note detection circuit 22 (corresponding to 5 in Figure 1) generates a root note signal. is detected, and the root tone signal is sent to the adder 23.

On the other hand, the hexadecimal counter 26 is operated by the clock, and the output of the hexadecimal counter 26 is the 1st, minor third, third, fourth, fifth, minor sixth, sixth, minor seventh in the coincidence gate 27. When the input conditions corresponding to each AND gate for
n), 7th, Dim
, the respective output pulses of the 0R gates for augmentation (Aug) are input to the multiplexer 28 through lines A, B, C, D, and E. Selected by code designation signal. The output pulse of multiplexer 28 is sent to latch circuit 25 via AND gate 29 at clock timing, and the content of counter 26 is temporarily stored by the pulse. Next, the root note signal of the root note detection circuit 22 and the latch circuit 25
The contents of the adder 23 are added, and the output of the adder 23 is converted into a 4-bit decimal number through a hexadecimal-decimal conversion circuit 24, that is, an addition circuit whose carry is controlled by an AND gate and an 0R gate circuit. , decoded by the decoder 30 and stored in the latch circuit 31. The output of this latch circuit 31 controls the gate 32 of the pitch name (C, C≠, . . . B) to output an accompaniment sound from the sound source, and the gate 7 of FIG.
sent to. FIG. 3a shows an example of the latch circuit 31 and gate 32, the former consisting of a diode and a CR time constant circuit, and the latter consisting of an AND circuit having the output of the latch circuit 31 and each sound source as inputs. Figure b shows the waveform 2 and gate 3 at point A of the latch circuit 31 for the decoded waveform 1 of the decoder 30.
FIG. 2 is an operation waveform diagram showing input sound source C-B3 and output C-B4 of No. 2; The outline of the configuration has been described above, and the operation will be explained in more detail.

When the hexadecimal counter 26 is counted by the clock and its output matches the input condition of the coincidence gate 27, for example, when the output of the counter 26 is "0000", it is 1 (ROOt).
AND gate, [0111] outputs a pulse when it matches the input condition of the AND gate of 5 (Maj), minor (Min), which indicates the code by the combination.
) etc., each output pulse of the 0R gate is connected to the line A-
A code designation signal is input to the multiplexer 28 via E to select a line, and the pulse of the selected line is sent to the latch circuit 25, which changes the output state of the counter 26 at that time. is memorized.

The contents of this latch circuit 25 are as shown in Table 2.
This is a 4-bit encoded version of degrees to minor sevenths. On the other hand, the root sound signal output from the root sound detection circuit 22 is the first root sound signal.
As shown in the table, the root sounds C, c,...B are encoded in 4 bits. These root tone signals in Table 1 and the contents of the latch circuit 25 in Table 2 are added by an adder 23 and
A hexadecimal digital output is obtained, which is input to a hexadecimal-decimal conversion circuit 25 and converted into a decimal digital output. Table 3 is an example of an input/output table of the hexadecimal to decimal conversion circuit 25 based on pitch names. The above-mentioned operation will be explained below using an example.

For example, when F minor (Fmln) is pressed on the lower keyboard, according to Table 1, the root note is sent to the adder 23 as "010
1” is input. Since it is minor, multiplexer 2
8, line B is selected, but line B has 1
Since the three (ANI) gate outputs of degrees, minor thirds, and fifths are connected, the output of the counter 26 is "0000j,"
0011" and "0111", a pulse is given to the latch circuit 25, and the respective counter outputs "0000"
”, “0011], and “0111” in the latch circuit 25.
to be memorized. These signals are added to the root signal [0101], and the adder outputs "0101L"10001, "11
Since this is a hexadecimal number, it is converted to a decimal number and output in the order of "0101", "1000", and "0000". This signal is nothing but the three tones of F and GC (F minor). This signal is decoded by a decoder 30 and stored in a latch circuit 31, whose output controls each gate 32 for each tone. With this configuration and operation, to perform accompaniment, the root note is specified by pressing one key on the accompaniment keyboard, and at the same time, a chord specification signal is applied externally, so that multiple accompaniment notes are played at once as described above. That's what you get.

In conventional single-key accompaniments, it was usually best to specify two types of chords, but with the present invention, despite the simple structure, many chords such as major, minor, seventh, diminutive, and augment can be obtained. It is clear that an effective accompaniment sound can be obtained and the operation is significantly easier. Furthermore, as shown in FIG. 2, the circuit is comprised of a normal logic circuit, with fewer wires and fewer elements, making it possible to realize a compact and inexpensive accompaniment device suitable for large-scale integrated circuits (LSI).

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the configuration of an embodiment of the accompaniment device of the present invention, Fig. 2 is a detailed explanatory diagram of the main part of the embodiment of the invention, and Figs. 3A and b are the main parts of Fig. 2. These are concrete circuit examples and operation waveform diagrams. In the figure, 1 is a sound source, 2 is an opening/closing circuit, 3 and 7 are gates, and 4
, 21 is a lower keyboard key switch circuit, 5 and 22 are root note detection circuits, 6 is a chord generation circuit, 8 is a rhythm pulse generator,
9 is a filter, 10 is an amplifier, 11 is an automatic bass accompaniment circuit, 23 is an adder, 24 is a hexadecimal-decimal conversion circuit, 2
5 is a latch circuit, 26 is a counter, 27 is a coincidence gate,
28 is a multiplexer, 29 is an AND gate, 30 is a decoder, 31 is a latch circuit, and 32 is a pitch name gate.

Claims (1)

[Claims] 1. A root note detection circuit that outputs a root note signal by pressing one key on an accompaniment keyboard, a counter operated by a clock from a clock generator, a coincidence gate that selects and derives the output of the counter according to a set chord, and a selection circuit that selects the output of the coincidence gate based on a signal from a separately provided chord designation means; a storage circuit that reads and stores the output of the counter when the output signal of the selection circuit matches a set chord signal; and the root note. An automatic accompaniment device comprising: an adder that adds the output of the detection circuit and the output of the storage circuit; and a musical tone signal conversion circuit that converts the output of the adder into a musical tone signal.