JPS6034120B2 - electronic musical instruments - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an electronic musical instrument using a timbre control filter.

2. Description of the Related Art Conventionally, electronic musical instruments are well known in which a sound source signal containing many harmonic components is added to a timbre control filter to obtain a musical tone signal having a desired timbre.

However, this key electronic musical instrument leads a number of sound source signals equivalent to the total number of keys on the keyboard (61 types of sound source signals for 61 keys) from the sound source circuit to a keyboard circuit that has a key switch corresponding to each key. Since the structure is such that the sound source signal corresponding to the pressed key is opened and closed by the key switch of the keyboard circuit and added to the formant filter, the number of wires connecting the sound source circuit and the keyboard circuit is large (61 keys). (61 wires), which had the disadvantage that the wiring around the keyboard circuit was extremely complicated.

That is, when the wiring around the keyboard circuit becomes complicated, not only does the manufacturing process become complicated, but it also leads to an increase in manufacturing costs and an increase in the size of the device. The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to reduce the number of connecting wires between a tone generator circuit and a keyboard circuit, and to simplify the circuit configuration.

According to this invention, the sound source circuit has a predetermined time slot assigned corresponding to a selected key based on the output of the keyboard circuit, and each signal of the predetermined time slot corresponds to a selected key. It consists of a multiple sound source device that outputs a time-division signal consisting of the amplitude value of a sound source waveform at a sound frequency specified by By adding it to a timbre forming filter, a musical tone signal with a desired timbre is obtained. That is, the present invention includes a frequency signal generating means that generates a frequency signal corresponding to the pitch of each key, a plurality of time slots that are sequentially assigned to each key, and a frequency signal that is assigned to each time slot in each time slot. a control pulse generating means for generating a control pulse for instructing a key, and a control pulse generator provided for each key, for instructing the frequency signal corresponding to the treble of the key and the time slot to which the key is assigned; a plurality of AND means for detecting the logical product of a pulse and a signal indicating a pressed state of the key; an OR means for synthesizing the outputs of the respective fund means to form a time-sharing signal; and an OR means for receiving the time-sharing signal. , and timbre control filter means for obtaining a musical tone signal of a predetermined timbre. The above-mentioned "control pulse" corresponds to "pulse OC~low B, low U.~me P2" shown in the following example, and the above-mentioned "signal indicating key press state" corresponds to the AND circuit 40CU of the following example. , corresponds to the signal on line OL. The invention will now be described in detail with reference to the embodiments of the accompanying drawings.

FIG. 1 is a block diagram schematically showing an electronic musical instrument according to the present invention. In a keyboard circuit 1, key switches corresponding to each key are arranged in a matrix circuit network, and matrix lines (input/output lines) of this matrix circuit network. is connected to a digital IC section 2 (in this specification, IC is used as an abbreviation for integrated circuit).

This digital IC section 2 includes a counter section 20, a sound source oscillation section 30 that generates a frequency corresponding to the pitch of each key, and a digital gate that receives signals from the counter section 20, the sound source oscillation section 30, and the keyboard circuit 1. 40 etc. The counter section 20 sequentially generates a pitch name pulse corresponding to each pitch name within one octave and an octave pulse corresponding to each octave, and the digital gate section 40 converts the pitch name pulse of the pressed key to the musical tone frequency of the key. Select periodically according to The output of the digital gate section 40 is applied with a clock removal filter 50' that passes only the audible frequency component, and the high-speed (high frequency) pitch name pulse component is removed.
The sound source frequency is extracted. This sound source frequency is subjected to timbre and volume control via a timbre control filter 60 and a volume controller 70, and is then outputted via an audio system 80. FIG. 2 shows the main part of the present invention, in which the keyboard circuit 1 includes 12 note names C, C#, D...A#, of each octave,
Line line IL, ~IL, 2 specifying B and the corresponding pitch name C
~ Types of octaves to which B belong (for example, the first octave U to the fourth octave U4 of the upper keyboard, and the first octave L to the fourth octave L4 of the lower keyboard)
Column lines OL, ~O (shown with respect to the first octave P, and the second octave P2 of the pedal keyboard)
L.

It is constituted by a matrix circuit network having.
The key switch is arranged via diodes to connect the row and column lines corresponding to the note name and octave of the key, the movable contact is connected to the row line, the fixed contact is connected to the column line, and the key When the switch is closed, the row and column lines are connected and conductive. The counter unit 20 includes a 12-decimal pitch name counter 21 that sequentially counts high-speed clock pulses (for example, IMHZ) as shown in FIG. It has a counter 22.

The counting output of the note name counter 21 is decoded by the decoder 23 into 12 different outputs, which produce note name pulses as shown in FIG. C,? C#, D, . . . OA#, ◇B are generated in sequence. Pitch name pulse ◇C~OB is 12 in 1 octave
These pulses correspond to the pitch names C to B, respectively, and are generated by sequentially circulating and occupying different time slots for each pitch name. The count output of the octave counter 22 is decoded by the decoder 24 into a 1G weight output, and the octave pulse ◇U, ~◇U4,? as shown in FIG. 3c is generated. L, ~
OL4,? P, to ◇P2 are generated sequentially. Octave pulse meU,~meUP2 is each octave type U of the keyboard,
~P2, respectively, and are pulses that are sequentially generated while occupying different time slots for each octave type, and whose pulse width is one octave worth of the pitch name pulse? C~? It is equal to the time of occurrence of B. That is, it has a pulse width equivalent to 12 periods of the pitch name pulse. Pitch name pulses ◇C to OB are input to the row lines IL to IL2 of the corresponding pitch names in the keyboard circuit 1, respectively, and determine the on/off state of the keyswitches with the same pitch name in each octave U, P2 in the relevant time slot. are detected at the same time. The sound source oscillation unit 30 includes 12 oscillators 31 that oscillate frequencies of each note C to B in the highest octave.
C, 31C#, ... 31A#, 31B and each oscillator 31
It has 12 sets of frequency dividing circuits 32C, 32C#, . . . 32A#, 32B that sequentially divide the oscillation frequencies of C to 31B to generate frequencies of each pitch name C to B in each octave. (For convenience, the oscillators 31C and 31B with pitch names C and B are
and only the frequency dividing circuits 32C and 32B are shown).

These oscillators 31C to 31B and frequency dividing circuits 32C to 3
2B respectively generate square wave signals of frequencies corresponding to the pitches of each key. Each of the frequency divider circuits 32C to 328 is constituted by a plurality of cascade-connected 1'2 frequency dividers OD, to OD4. A plurality of AND circuits 40CU (as many as the total number of keys) corresponding to each key in the digital gate section 4. ,40C
U2,...4 0CP2,...4 0BU,,4 0B
U2, . . . has 40 BP2.

In addition, in this embodiment, 4 feet sound 4' and 8 feet 8
', the same number of AND circuits 41CU, 41CU2,...4 1CP2,...
It has 4 1BU,, 4 1BU2,...418P2. AND circuits 40CU and 40BP2 correspond to 4 feet, and AND circuits 41CU and 41BP2 correspond to 8 feet. In the figure, each AND circuit 40CU,
~41BP2 input end connection mode is for each AND circuit 40
The signals of the vertical lines that intersect with the single horizontal line added to the input terminals of CU, 41BP2 by circles are input to the respective AND circuits. AND circuit 40 for reference
When CU and 41CU are used as an example, the connection mode is shown in the usual way as shown in FIG. Each asodo circuit 40C
Four inputs are added to U, ~41BP2. That is,
■ A square wave signal from the sound source oscillator 30 corresponding to the frequency of the key corresponding to the AND circuit; ■ A pitch name pulse (?C~OB) from the decoder 23 corresponding to the pitch name of the key;
one of the following), ■ an octave pulse from the decoder 24 representing the octave type to which the key belongs (◇
U, ~? The following four inputs are input to each AND circuit 40CU, -41BP2: one of P2), and (one of OL. to CLo) of the column line corresponding to the octave type to which the key in question belongs in the keyboard circuit 1. can be added respectively. For example, in the case of AND circuit 40CU, ■Oscillator 31
Frequency signal of C note in the highest octave 4 feet from C, ■ Pitch name of C note Pulse? C, (1) octave pulse JU of the first octave U of the upper keyboard, and (2) column line OL, output of the first octave U of the upper keyboard are input, respectively. In addition, in the case of the AND circuit 41CU, the inputs of ■ to ■ above are the same as the AND circuit 40CU, but since it is an 8-foot tone, the input of ■ is the output of the C tone oscillator 31C divided into 1'2. A frequency signal is applied. AND circuit 40CU, ~
Of the input conditions (1) to (2) of 41BP2, inputs (2) to (2) are always satisfied, and input (2) is satisfied in accordance with the depression of the key. For example, if the key of the C note in the first octave U of the upper keyboard is pressed, the key switch KC of the keyboard circuit 1 is closed, and the column line CL of the same circuit 1 is closed.
outputs the pitch name pulse JC of the C note.

The pressed key is specified by the type of column line where the output is occurring and the type of note name pulse that is occurring there. Therefore, from the column line CL of the AND circuit 40CU (also the AND circuit 41CU, but for convenience of explanation, we will consider only the 4-foot note) corresponding to the C key of the first octave U of the upper keyboard. Pitch name pulse on the input side? C is added. This note name pulse? C is also added to the same AND circuit 40CU from the decoder 23,
When the time scale is reduced from that in FIG. 3, the occurrence occurs as shown in FIG. 5a. Also, the octave pulsema U of the first octave U of the upper keyboard as shown in Fig. 5b,
is also added to the same AND circuit 40CU, and this octave pulse serves to temporally allocate the note name pulse to each octave. Therefore, in the AND circuit 40CU, one pitch name pulse is generated every time an octave pulse OU is generated? C is selected. Furthermore, the AND circuit 40CU receives the upper keyboard first octave U. from the oscillator 31C. C of the height of
A sound square wave frequency signal is added as shown in Figure 5c, and every half cycle of the waveform in which this square wave signal becomes signal 1 (active level) coincides with the generation timing of the octave pulse U. The note name pulse? C is periodically connected to the band circuit 40CU.C as shown in FIG. 5d. Selected output is made from. Clock pulse here? If ・is 8MHZ, then the frequency of octave pulse U, is 8MHZ ÷ 12 ÷ 10
Mainly 40k days, about 2, octave pulse? The frequency of the note name pulse JC selected in synchronization with U, is also about 4 days, which is higher than the audible frequency. On the other hand, the square wave frequency of note C is 2093Hz at the highest octave.
Therefore, a pitch pulse ◇C of a fixed degree of about 1 is selectively outputted as shown in the figure during a half cycle. The other AND circuits 40CU2 to 41BP2 also operate in the same manner as described above.

Here, in each AND circuit 40CU, ~4 1BP2, octave pulse JU, ~? P2 selects pitch name pulses from G C to M B for each octave type with a time lag, so all AND circuits 40CU, ~4
It is impossible for the time slots of B to match in the pitch name pulse ◇C~ selectively output from 1BP2. That is,
Regarding different note names, the time slots will not match because the note name pulses ◇C to JB are originally different, but if the octave types U and ~P2 are different and the same note name C to B, the time slots will generally be the same. I will do it. Times like this. If the sounds match, it becomes impossible to identify which octave the sound belongs to when performing synthesis processing using a digital circuit (OR circuit) at a later stage. For example, if pitch name pulses are selected in response to square wave frequency signals of the same note names with different pitches of one octave, and then these selected note name pulses are synthesized into one signal by an OR circuit, both note name pulses are combined into one signal using an OR circuit. Pulse Times. If the hits match, a problem arises in that only low frequency components are output from the OR circuit. For this reason, the octave pulse ◇U. ~CP2 is configured to select each pitch name pulse C~OB with a time shift for each octave type, and C~OB is selected periodically according to each square wave frequency signal.
The time slots were made to not match. Therefore, the outputs of the AND circuits 40CU and 41BP2 can be combined into a small number of output lines using an OR circuit, and the number of output connection pins of the digital IC section 2 can be reduced. In FIG. 2, each AND circuit 40CUl to 40
The outputs of BP2, 4 1CU, to 4 1BP2 are organized by keyboard type.

Upper keyboard U in AND circuit 40CU, ~40BP2,
The outputs of the AND circuits 40CU and 40BU4 corresponding to ~U4 are respectively input to the OR circuit 42, and the upper keyboard tone UK4' for 4 feet is compositely output. Also, AND circuit 40
In CU, ~40BP2, the outputs of the AND circuits 40CL and ~40BL4 corresponding to the lower keyboard L, ~L4 are input to the OR circuit 44, respectively, and the lower keyboard tone LK4' for 4 feet is inputted to the OR circuit 44.
is output as a composite. AND circuit 40CU, ~40BP2
AND circuit 4 corresponding to pedal keyboard P, ~P2 in
The outputs of 0CP, 40BP2 are respectively input to an OR circuit 46, and a 4-foot pedal keyboard tone PK4' is output as a result. In addition, the outputs of the AND circuits corresponding to the upper keyboard or the pedal keyboard in the AND circuits 41CU, 41BP2, respectively, are similarly applied to the OR circuits 43, 45, and 47, respectively, and from the same OR circuits 43, 45, and 47, the outputs of the AND circuits corresponding to the upper keyboard or the pedal keyboard are respectively applied. Upper keyboard sound UK8', lower keyboard sound LK8', and pedal keyboard sound PK8' are output, respectively. In FIG. 2, the connection mode of the input terminals of the OR circuits 42 to 47 is an AND circuit 40C.
Illustrated in the same manner as for U, ~41BP2. For example, the C note of the first octave U of the upper keyboard and the second octave U2.
Assuming that the keys of C note are pressed at the same time, oscillator 3
Since the square wave frequency signals from 1C and 1'2 frequency divider OD have the relationship as shown in FIG. 6a and b, the AND circuit 40
Outputs as shown in c and b of the figure are generated from CU and 40CU2, respectively. Figure 6 shows a smaller time scale than Figure 5, but the C
The spacing is not drawn to scale in FIG. As is clear from the figure, the period T, , T2 at which the pitch name pulse C is selected in an interlocutory manner coincides with the period T, , T2 of the musical tone frequency. The outputs of the AND circuits 40CU, 40CU are added to the OR circuit 42, and the outputs from the OR circuit 42 are
A composite signal UK4' is output as shown in FIG.
This signal UK4' is composed of coarse and fine pulses, and the pulse interval is close in the part where the amplitude level of the musical tone frequency signal is superimposed, and the pulse interval is coarse in the part where it is not superimposed.
In this way, the signals UK4' to P combined in the form of coarse and fine pulses are
K8' is output from each OR circuit 42 to 47, and is supplied to the subsequent circuit as the output sound source signal of the digital IC section 2.

As shown in Figure 7, the output sound source signal UK of section 2 is digitally
4' to PK8' are added to clock removal filters 51 to 56 to remove high frequency (above audible frequency) pitch name pulse components and extract only musical tone frequency (square wave frequency) components.

The filters 51 to 56 can be constructed by, for example, a low-pass filter having a cutoff frequency of a high frequency that is an inaudible frequency. The clock component of the sound source signal UK4' shown in FIG. 6e is removed by the filter 51, and the sound source signal UK4' shown in FIG. get. This audio frequency signal component is almost the same as the waveform obtained by superimposing the waveforms shown in FIGS. 6a and 6b in an analog manner, and it can be seen that a waveform obtained by substantially superimposing and synthesizing square wave frequency signals is obtained. The outputs of the clock removal filters 51-56 are applied to the corresponding timbre control filters 61-66, respectively, and timbre control is performed for each keyboard type and for each foot note 4', 8'.

Note that the resistance R,, R2 or R3, R4 or R5, R6
The frequency levels of the 4-foot sound and the 8-foot sound are added for each key through the 8-foot filter 62,
64 and 66, this is to form a stepped waveform containing many harmonic components. After the outputs of the timbre control filters 61 to 66 are individually adjusted in volume with volume adjustment resistors 71 to 76,
The sound is produced via the audio system 80. In the examples shown in FIGS. 2 and 7, six OR circuits 42 to 47 are used in the digital IC section 2, and the number of output connection pins is Although the number of output connection pins is now six, the number of output connection pins can be further reduced if timbre, volume, etc. are controlled in common for all keyboards.

For example, as shown in FIG. 8, all the outputs of the AND circuits 40CU and 40BP2 for 4 feet of the digital gate section 40 are input to the OR circuit 48, and all the outputs of the AND circuits 41CU and 41BP2 for 8 feet are input to the OR circuit 48. If configured to be input to the circuit 49, the sounds of all the keys will be combined into one line. Of course, the 4-foot and 8-foot sounds are combined on different lines, but if the configuration is such that only the standard 8-foot sound can be produced, only a single OR circuit can be used. In the above-mentioned embodiment, the counter section may be constructed of a ring counter such as a shift register or the like, and the arrangement of the key switches of the keyboard circuit 1 or the construction of the sound source oscillation section 30 is not limited to the illustrated example.

Also, the processing circuit (filter, etc.) after the digital IC section 2
The configuration of can also be changed in various ways. Furthermore, in the above embodiment, note name pulses C~◇B are input to the keyboard circuit 1, but octave pulses JU, ~? P2 may be input. In this case, the lines CL to OLo corresponding to the octave types are regarded as row lines, and the row lines OL, to OL,.

The U. ~Enter JP2 separately. And the line IL~yama corresponding to each note name,
2 as a column line, and this column line IL. ~IL, 2
The configuration may be such that the output (octave pulse) is derived from the key press in response to the key press. Therefore, the manner in which the input terminals of the AND circuits 40CU to 41BP2 in the digital IC section 2 are connected is also different from that shown in FIG. That is, the output of the column line ratio, .about.IL,2 of each pitch name becomes one input of the AND circuits 40CU, .about.41BP2 corresponding to the same pitch name, respectively. Since the output timings of these column lines IL to IL2 have already been distinguished by octave type, the octave pulses ◇U, ~? which are the outputs of the decoder 24 are different. It is no longer necessary to input P2 to the AND circuit 40CU, ~41BP2,
The inputs of the AND circuits 40CU, ~41BP2 are the signal from the sound source oscillator 30 and the pitch name pulse ◇C from the decoder 23.
~OB and the outputs of the column lines IL~IL2 of the keyboard circuit 1 can be reduced to three inputs. As explained above, according to the present invention, the number of wires around the keyboard circuit can be significantly reduced, thereby simplifying the circuit configuration, simplifying the manufacturing process, and reducing manufacturing costs.

In addition, the structure is such that the time-division multiplexed sound source signal is directly added to the timbre-forming filter to impart timbre.
A mixing circuit or the like is not required, and the circuit can be simplified from this point as well. Furthermore, since the timbre is imparted by the timbre-forming filter, musical tones with various tones can be obtained depending on the characteristics of the timbre-forming filter.

[Brief explanation of the drawing]

Fig. 1 is a schematic block diagram showing an embodiment of the electronic musical instrument of the present invention, Fig. 2 is a detailed block diagram showing the main parts of the embodiment in relation to a keyboard circuit, and Fig. 3 is a timing chart of various pulses. , FIG. 4 is a diagram explaining the input terminal connection mode of the AND circuit in FIG. 2, FIG. 5 is a timing chart showing input/output examples of each part in FIG. 2, and FIG. 7 is a block diagram showing an example of the analog processing system in the embodiment of FIG. 1, and FIG. 8 is an abbreviated block diagram showing a modification of FIG. 2. 1...Keyboard circuit, 2...Digital IC section,
20... Counter section, 30... Sound source oscillation section, 40... Digital gate section, 80... Audio system. Figure 1 Figure 3 Figure 8 Figure N Sphere Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1. Frequency signal generating means that generates frequency signals corresponding to the pitch of each key, sequentially allocating a plurality of time slots to each key, and instructing each time slot which key is assigned to that time slot. a control pulse generating means for generating a control pulse for each key, and a control pulse generating means for instructing the frequency signal corresponding to the pitch of the key and a time slot to which the key is assigned; a plurality of AND means for detecting the logical product of signals indicating the pressed state of a key; an OR means for synthesizing the outputs of the respective AND means to form a time-sharing signal; and receiving the time-sharing signal;
timbre control filter means for obtaining a musical tone signal of a predetermined timbre;
An electronic musical instrument with