JPH07152375A - Chord detection device - Google Patents

Abstract

PURPOSE:To reduce a memory capacity by detecting a chord through the use of a pitch name in a pitch information when a chord is not detected by a first detection device which detects a chord in accordance with the relative relationships among inputted sound pitch information. CONSTITUTION:The device consists of a keyboard 1 to which a player inputs a chord and a melody, a switch group which consists of switches to select various accompaniment patterns, a CPU 3 which controls the entire device, a special chord table 4 which stores special chord patterns and a conventional chord table 5 which stores conventional chord patterns. In order to detect a normal chord which is often used, a conventional scheme is used, that is, a pattern in that corresponding pits of the keyboard sounds are made to '1' and a pattern of the table 5 are shifted and a matching is made. In order to detect a special chord which is not frequently used or the chord in which elementary sounds are omitted, the table 4, which is constituted by the information indicating the relative relationships among absolute sound pitches is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chord detecting device for detecting chords from pitch information.

[0002]

2. Description of the Related Art Conventionally, a so-called chord detection device for detecting chords from pitch information has been proposed. As such a chord detection device, the present applicant stores, as table data, a bit pattern in which a root note (Root) is "C" and a bit of a note name corresponding to each chord type (Type) is "1". A configuration in which chords are detected by matching the bit pattern of the table data while shifting the temporarily stored pattern with the bit of the note name of the key depression sound (pitch information) as "1" (special feature) Kosho 57-
16359) or a bit pattern of a note name corresponding to the root note (Root) and type of the chord is stored as table data, and the bit corresponding to the note name of the key depression note is temporarily set to "1". It has been proposed that a chord is detected by matching with a pattern that is stored in memory (see Japanese Patent Publication No. 63-39078).

[0003]

However, in the above proposed conventional chord detection device, even if the chords are composed of the same pitch name, different chords or root notes of chords are generated when the relative relationship of absolute pitch changes. It was not possible to detect chords (hereinafter, these chords are referred to as "special chords") when the keys are not pressed.

FIG. 7 is a diagram for explaining the disadvantage of the above-mentioned prior art, in which the chords 101 to 104 are C ₉ chords (C
Nine chord) and chords 105 and 106 are Em ₇
Shows the chord (E minor 7th chord). Here, the chord 101 and the chord 105 have the same constituent name, and the chord 101 and the chord 106 are the latter constituent "G".
Is one octave higher than the former constituent sound "G". Further, chords 101 to 106 are examples of chords in which no root note or the like is pressed.

For example, when the chords 105 and 106 are detected by the conventional chord detecting device, the detection result is chord 1
Matches the detection result of 01. However, the chord is actually 10
It is more appropriate to distinguish 5, 106 as Em ₇ chords.
Further, for example, since the chords 101 to 104 are abbreviations of the root chords of the chord of C ₉ , it is very difficult to detect the chords 101 to 104 by the conventional chord detection device.

It is possible to detect a desired chord by increasing the amount of table data and storing the relative relationship of all chords to be detected. However, this causes problems such as an increase in chord detection time, an increase in memory capacity, and an accompanying increase in cost.

The present invention has been made in view of the above problems, and is capable of detecting a special chord and reducing the chord detection time, the memory capacity, and the associated cost. An object is to provide a chord detection device.

[0008]

In order to achieve the above object, the present invention provides a pitch information inputting means for inputting pitch information and a chord detecting according to a relative relation between the inputted pitch information. One chord detecting means and a second chord detecting means for detecting a chord according to the note name of the inputted pitch information, and the second chord detecting means when the chord is not detected by the first chord detecting means. And a control unit for detecting a chord by the chord detection unit.

[0009]

According to the pitch information input by the pitch information inputting means, the control means detects the chord by the first chord detecting means, and as a result, when the chord is not detected, the second chord detecting means. Detected by.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of an automatic accompaniment apparatus to which the chord detection apparatus according to the present invention is applied.

Referring to FIG. 1, the automatic accompaniment apparatus of this embodiment has a keyboard 1 for a performer to input chords, melodies and the like.
And a switch group 2 including switches for selecting various accompaniment patterns, and a CPU 3 that controls the entire apparatus.
, A special chord table 4 for storing special chord patterns, a normal chord table 5 for storing normal chord patterns, a program memory 6 for storing programs and data executed by the CPU 3, and a CPU 3 execution The working memory 7 for temporarily storing the calculation result and various input information, and the automatic accompaniment device for performing the automatic accompaniment according to the chord information output by pressing the keyboard 1 and the accompaniment pattern selected by the switch group 2. 8 and a tone generator (TG) 9 for outputting a tone signal in accordance with the event data output by pressing the keyboard 1.

The output side of the automatic accompaniment device 8 and the output side of the tone generator 9 are connected to the input side of a mixer 10 for mixing the tone signal outputs of the respective elements 8 and 9, and the output side of the mixer 10 is , Is connected to a sound system 11 for converting a mixed musical tone signal into a musical tone, and the above-mentioned respective elements 1 to 9 are mutually connected via a bus 12.
The elements 4 to 6 are composed of a ROM, and the element 7
Is composed of a RAM.

FIG. 2 is a diagram showing an example of table data stored in the special chord table 4 of FIG. 1. Each table data in FIG. 2 is the chord 10 of FIG. 7 from the top.
Corresponds to the chord of C ₉ of 1-105.

Further, in the figure, D (1) represents the difference between the lowest pitched note of the notes overlapped by the keyboard 1 and the next pitched note, and a semitone is one unit. As Similarly, D (2) indicates the difference between the lowest pitched sound and the next pitched sound, and D (3) is the lowest pitched sound and the next further pitched sound. It shows the difference with. It should be noted that when there are three tones that are pressed repeatedly, D (3) is "none".

For example, the first data in the table data of FIG. 2, that is, the data corresponding to the chord 101 of FIG.
Since the difference between the constituent sound 101 ₂ and the constituent sound 101 ₁ is “2” in semitone units, and the difference between the constituent sound 101 ₃ and the constituent sound 101 ₁ is “5” in semitone units, it is C ₉ . At this time,
The difference between the constituent sound 101 ₁ and the root sound (“C”) is stored in the “root (root sound)” column, and the stored value (“1”) is stored.
The root note ("C") is calculated by adding 0 ") and the value of the constituent sound 101 _{1. It} should be noted that the characters in parentheses that are shown together with the value in the" Root "column are shown. (A #) indicates the note name (A #) when the value (“10”) is counted from the position of “C”. The "Type" column indicates the type of chord.

FIG. 3 is a diagram showing table data stored in the ordinary chord table 5 of FIG. In the figure,
In each data, the bit of the note name of the constituent sound of the chord is set to "1" according to the chord type based on "C",
The other bits are set to "0". For example, m
₇ (Minor Seventh) is "C", "D #", "A"
Since it is composed of the constituent sounds of "#", a bit corresponding to this constituent sound is set. A chord detecting method using this normal chord table will be described later.

The control process executed by the CPU 3 of the automatic accompaniment apparatus configured as described above will be described below with reference to the flow charts of FIGS.

FIG. 4 is a flowchart showing the processing procedure of the main routine.

First, various initial settings are made in step S1, and it is determined in step S2 whether or not there is a key depression (key event) of the keyboard 1. If there is a key event, a key event processing subroutine described later is executed. On the other hand, when there is no key event (step S3), step S3 is skipped and the process proceeds to step S4. Step S
4, it is determined whether or not there is an event of the style selection switch (not shown) of the switch group 2, and when there is an event, the number of the selected style (for example, arpeggio etc.) is assigned to the working memory of FIG. Area ST of 7
YL (Hereinafter, the content is called "style STYL")
(Step S5), and the style STYL is output to the automatic accompaniment apparatus 8 of FIG. 1 (step S6). On the other hand, when it is determined in step S4 that there is no on event of the style selection switch, steps S5 and S6 are skipped and the process proceeds to step S7.

In a succeeding step S7, it is determined whether or not there is an on event of a start switch (not shown) of the switch group 2, and when there is an on event, a start signal for starting the automatic accompaniment device 8 is output. (Step S8), on the other hand, when there is no on event, step S8 is skipped and the process proceeds to step S9.

Further, in step S9, it is determined whether or not there is an on event of the stop switch (not shown) of the switch group 2, and when there is an on event, a stop signal for stopping the automatic accompaniment device 8 is output. (Step S10), on the other hand, when there is no on event, step S10 is skipped and the process proceeds to step S11.

In step S11, after performing the other processes of the above-described process, the process returns to step S2, and the processes of steps S2 to S11 are repeated.

FIG. 5 is a flow chart showing the detailed procedure of the key event processing subroutine of step S3 of FIG. 4, and this subroutine detects chords.

First, in step S21, it is determined whether a key is pressed (key on) or released (key off). When the key is pressed, a sounding process corresponding to the key is performed (step S22). The key code is added to the list KC () (step S23), and the list K is added.
Sort the key codes in C () in ascending order (sort)
(Step S24), the number of elements of the list KC () is stored in the area N of the working memory 7 (hereinafter, the content is referred to as "element number N") (step S25). Here, in this embodiment, an area called a list KC () is secured in a predetermined area of the working memory 7, and when a key is pressed, the key code is stored in the list KC () and sorted. When the key corresponding to the key code stored in KC () is released, the key code is listed K
Various processes are executed according to the key code deleted from C () and stored in the list KC (). The key codes stored and sorted in the list KC () are sorted in ascending order of key code KC (i) (i
= 0, 1, ...).

In the following step S26, the number N of elements is "3".
It is determined whether or not the above, and when it is "3" or more, it is determined whether or not the number of elements N is "3" (step S2).
7) As a result, when the number N of elements is larger than "3", the number N of elements is set to "4" (step S28), while when the number N of elements is "3", step S28 is skipped and the process proceeds to step S29. .

In step S29, a sub-routine for chord detection processing, which will be described later, is executed, and then this sub-routine processing is terminated.

On the other hand, the number of elements N
When is smaller than "3", steps S27 to S29 are skipped and the present subroutine processing is ended.

That is, the processes of steps S26 to S28 are performed because the present embodiment is configured to detect only chords having three or four constituent tones.

On the other hand, when the key is released in the determination in step S21, the mute processing is performed (step S30), the key code is deleted from the list KC () (step S31), and then this subroutine processing is ended.

FIG. 6 is a flowchart showing the detailed procedure of the chord detection processing subroutine of step S29 of FIG.

First, in step S41, the list KC ()
The difference between the smallest key code KC (0) and the other key code KC (i) is calculated from the sorted and stored key codes in the area D of the working memory 7.
(I) (i = 1, ..., N−1) is stored (hereinafter, the content is referred to as “difference D (i)”).

Next, in step S42, the above step S
The difference D (i) calculated in 41 is matched with the table data of the special chord table 4 in FIG. 2, the result of the matching is determined in step S43, and if not matched, the process proceeds to step S44.

In step S44, the key code KC
The bits of the area CHRD of the working memory 7 corresponding to the note names (0) to KC (i) are set to "1" and the other bits are set to "0". Where the region CHRD
Has the same bit configuration as the table data of the normal chord table 5 shown in FIG.

Next, in step S45, the area CHRD is shifted and matched with the table data of the ordinary chord table 5, and the result is discriminated in step S46.
When matching is performed, the number of shifts (the number of shifts becomes the root note of a chord) is stored in the area ROOT of the working memory 7 (hereinafter, the content thereof will be referred to as "root ROOT").
Stored in the area TYPE of the working memory 7 (hereinafter referred to as "type TYPE").
"E") (step S47). Further, after the route ROOT and the type TYPE matched in step S48 are output to the automatic accompaniment device 8, the present subroutine processing is ended.

On the other hand, if it is determined in step S46 that no chord is detected when no matching is found, step S4 is performed.
This processing is terminated by skipping steps 7 and 49.

On the other hand, the determination in step S43, that is,
In the determination of matching with the table data of the special chord table 4, when matched, the route and type obtained from the table data are respectively set to the regions ROOT and T.
The result obtained by adding the root ROOT and the key code KC (0) to the result stored in the YPE (step S49) and dividing the root ROOT and the key code KC (0) is divided by 12 to find the remainder (chord root note). After storing in the root ROOT (step S50), the process proceeds to step S48, and the matched root ROOT and type TYPE are output to the automatic accompaniment device 8.

As described above, according to the present embodiment, in order to detect a chord that omits a special chord or root note that is rarely used, it is composed of information indicating a relative relationship of absolute pitches. In order to detect a commonly used normal chord using the special chord table 4, the pattern in which the corresponding bit of the key depression sound is set to "1" and the pattern of the normal chord table 5 have been proposed. Since the method of matching while shifting is used, it is possible to detect special chords and the like, and it is also possible to reduce the memory capacity used for chord detection.

In this embodiment, the method described in Japanese Patent Publication No. 57-16359 described in the conventional example is used as the conventional chord detection method, but the method is not limited to this. The method described in Japanese Patent No. 39078 may be used.

Further, in the present embodiment, only one special chord is determined from the special chord table 4, but there may be a plurality of special chords. In that case, a rule for determining which of a plurality of chords should be decided according to the chord detected last time is provided.

[0041]

As described above, according to the present invention,
Pitch information input means for inputting pitch information, first chord detection means for detecting a chord in accordance with the relative relationship of the inputted pitch information, and a pitch name of the inputted pitch information It has a second chord detecting means for detecting a chord and a control means for detecting the chord by the second chord detecting means when the chord is not detected by the first chord detecting means, so that a special chord is detected. In addition, the chord detection time can be reduced, the memory capacity can be reduced, and the cost can be reduced accordingly.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of an automatic accompaniment apparatus to which a chord detection apparatus according to the present invention is applied.

FIG. 2 is a diagram showing table data stored in a special chord table 4 of FIG.

3 is a diagram showing table data stored in a normal chord table 5 in FIG. 1. FIG.

FIG. 4 is a flowchart showing a processing procedure of a main routine.

5 is a flowchart showing a detailed procedure of a key event processing subroutine of step S3 of FIG. 4. FIG.

FIG. 6 is a flowchart showing a detailed procedure of a chord detection process subroutine in step S29 of FIG.

FIG. 7 is a diagram for explaining the problems of the conventional example.

[Explanation of symbols]

 1 keyboard (pitch information input means) 3 CPU (control means) 4 special chord table (first chord detection means) 5 ordinary chord table (second chord detection means)

Claims (1)

[Claims] 1. A pitch information inputting means for inputting pitch information, a first chord detecting means for detecting a chord according to a relative relationship of the inputted pitch information, and the input pitch information. Second chord detecting means for detecting a chord according to a note name and the first chord detecting means
A chord detection device, comprising: a control unit that detects the chord by the second chord detection unit when the chord is not detected by the chord detection unit.