JPS5840198B2 - Denshigatsuki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an electronic musical instrument equipped with a sound source that oscillates a frequency corresponding to the pitch of each weight of a keyboard.

Conventionally, electronic musical instruments are equipped with a sound source that oscillates at a frequency corresponding to the pitch of each weight on the keyboard, and the desired frequency signal is selected from the sound source in response to a key press. The number of sound source signals corresponding to the number of keys (for 61 keys, 6
(one sound source output) had to be individually routed to the keyboard circuit.

For this reason, the number of connection lines between the keyboard circuit and the sound source circuit is equal to the number of keys, and when converting other circuits (for example, a sound source circuit) other than the keyboard circuit into an IC, this IC connected to the keyboard circuit is required.
The number of connection pins in circuits has become enormous (e.g. 61
Book).

Generally, the price of an IC circuit increases as the number of pins increases, so it is inevitable that the manufacturing cost of the entire electronic musical instrument will increase.

Therefore, in the specification of Japanese Patent Application No. 146048/1984, the title of the invention is "Electronic Musical Instrument," it is proposed that the number of connection lines between the keyboard circuit and other circuits be reduced to promote the use of IC circuits. Electronic musical instruments have been proposed, but the gate circuit that selects each sound source frequency signal oscillated by the sound source circuit must be configured with an analog processing type gate circuit that passes through and outputs the analog input frequency signal as it is. , it is desirable to further improve it in order to completely convert it into a digital IC.

This invention was made in view of the above-mentioned circumstances, and is designed to enable all of the sound source circuits connected to the keyboard circuit to be digitally processed, making it easy to integrate them into ICs, and also to reduce the wiring from the keyboard circuit. The purpose is to simplify the process and reduce the number of connection pins when integrated into an IC.

For this purpose, in the present invention, each key switch is set to L in the keyboard circuit to name each note within one octave (12 tone scale notes).
arranged in a matrix circuit network consisting of rows corresponding to the notes and columns representing the octave to which the note name (scale note) belongs, and connected to the sound source circuit section via each matrix line of this matrix-like keyboard circuit, A tone salt pulse that is generated sequentially at high speed for each note name within one octave is input into each of the corresponding row lines, or the note name pulse is generated sequentially for each octave type with a pulse width corresponding to a time width of one octave. The device is configured to input an octave pulse to each of the corresponding column lines and derive information representing the on/off state of each key switch from the other column line or row line.

Then, an AND circuit provided for each key determines the suppression of the key according to the output of the matrix keyboard circuit, and also determines the suppression of the key according to the octave pulse of the octave to which the pressed key belongs and the pitch frequency of the key. The present invention is characterized in that the pitch name pulse corresponding to the pressed key is periodically selected, and a musical sound waveform is obtained based on the periodically selected high-speed pitch name pulse.

Furthermore, even if two or more pressed keys have the same note name, the octave types to which they belong differ, so the corresponding octave pulses are generated at different times, and therefore each note name pulse selected in the AND circuit of the duplicate key is There will be no duplicate selection output at the same point in time.

Therefore, regardless of the octave type, the outputs of the AND circuits can be combined into one digital line using a single OR circuit, and the number of output connection pins can be extremely reduced. have

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 duplicate keys are arranged in a matrix circuit network, and the matrix lines (input/output lines) of this matrix circuit network are digital. It is connected to an IC section 2 (in this specification, IC is simply 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 frequencies corresponding to the pitches of duplicate keys, and a digital game that uses signals from the counter section 20, the sound source oscillation section 30, and the keyboard circuit 1 as human power). 40 etc.

The counter section 20 sequentially generates the pitch name pulse and octave pulse described above, and the digital gate section 40 periodically selects the pitch name pulse of the pressed key in accordance with the musical tone frequency of the key.

The output of the digital gate section 40 is applied to a clock removal filter 50 that passes audio frequencies, removes high-speed (high frequency) pitch name pulse components, and extracts the sound source frequency.

This sound source frequency is subjected to timbre and volume control via a timbre control filter 60 and a volume controller TO, and then produced via an audio system 80.

FIG. 2 shows the main part of this invention, in which the keyboard circuit 1 has 12 note names C, C#, D, etc. in each octave.
・・The type of octave (41
J represents the first octave U1 to the fourth octave U4 of the upper keyboard, the first octave L to the fourth octave L4 of the lower keyboard, and the first octave P1 and the second octave P2 of the pedal keyboard. It is constituted by a matrix circuit network having lines OL and 0L1o.

The key switches are 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 corresponding row and column lines are connected and conductive.

The counter section 20 includes a decimal pitch name counter 21 that sequentially counts high-speed clock pulses φ (for example, IMHz) as shown in FIG. 3a, and a decimal octave counter that divides the output of this pitch name counter 21. 22.

The count output of the note name counter 21 is decoded into 12 outputs by the decoder 23, and the note name pulses φC2φC#, φD, . . . - φA#, φ as shown in FIG.
B are generated sequentially.

Pitch name pulse φC ~ φB is 120 pitch C within 1 octave
-H, and these pulses are generated by sequentially circulating and occupying different time slots for each note name.

The count output of the octave counter 22 is sent to the decoder 24 by I
The octave pulses φU1 to φU4 . are decoded into O different outputs as shown in FIG. φL1 to φL4. φP
1. φP2 is generated sequentially.

The octave pulses φU□ to φP2 correspond to the octave types U1 to P2 of the keyboard, respectively, and are pulses that are generated by sequentially circulating, occupying different time slots for each octave type, and whose pulse width is is equal to the generation time of the pitch name pulses φC to φB of 1 octa-1 minute.

In other words, it has a pulse width of 12 periods of the pitch name pulse, and
Ru.

The pitch name pulses φC to φB are input to the row lines L1 to IL, 2 of the corresponding pitch names in the keyboard circuit 1, respectively, and the key switches of the same pitch name in each octave U1 to P2 are turned on and off in the corresponding time slot. The conditions are detected simultaneously.

The sound source oscillator 30 generates each note C-B in the highest octave.
12 oscillators 31 C, 31 each oscillating the frequency of
12 sets of frequency dividing circuits that sequentially divide the oscillation frequencies of C#, ---1, -31A#, 31B and each oscillator 31C to 31B to generate frequencies of each pitch name C-B in each octave, respectively. 32C, 32C#, -32A
#, 32B (for convenience, only the oscillators 31C, 31B and the frequency dividing circuits 32C, 32B with pitch names C and B 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 the matching keys.

Each of the frequency dividing circuits 32C to 32B is constituted by a plurality of vertically connected frequency dividers OD to OD4.

The digital gate section 40 includes a plurality of AND circuits 40CU1, 40CU2°40 (as many as the total number of keys), each corresponding to a duplicate key.
CP2. ----------40BU1.40BU2.
-Song--It has 40 BP2.

In addition, in this embodiment, since it is possible to generate each of the 4-foot note 4' and the 8-foot note 8', the same number of AND circuits 41CU1, 41CO2, -+-, -...-41C
P2.・-・・-・-41BU, ,41 BU2. −
・－・－・・It is equipped with 41BP2.

In the figure, the connection mode of the input terminal of each AND circuit 40CU1 to 41BP2 is
The signals on the vertical lines that intersect with the single horizontal line at the input end of the circuit are input to the respective AND circuits.

For reference, the connection mode is shown in the usual way using AND circuits 40CU1 and 41001 as an example, as shown in FIG.

Four inputs are added to each AND circuit 40CU, to 41BP2.

That is, (1) a square wave signal from the sound source oscillator 30 corresponding to the frequency of the key corresponding to the AND circuit; (2) a pitch name pulse (
one of φC to φB), ■ an octave pulse from the decoder 24 representing the octave type to which the relevant key belongs (one of φU1 to φP2), and ■ an octave pulse to which the relevant key belongs in the keyboard circuit 1. The output of the corresponding column line (any one of OL1 to 0L1o), 04 human power, is applied to each AND circuit 40CU, to 41BP2, respectively.

For example, in the case of an AND circuit 40CU□, ■ the frequency signal of the highest octave C tone of 4 feet from the oscillator 31C, ■
Pitch name of C note Pulse φC1■ Upper keyboard 1st octave U□
octave pulse φU□, ■upper keyboard 1st octave U
The column line OL□ output of □ is inputted, respectively.

In addition, in the case of the AND circuit 41CU1, the inputs of ■ to ■ above are the same as those of the AND circuit 40CU, but since the input is an 8-foot tone, the input of ■ is added with a frequency obtained by dividing the output of the C tone oscillator 31C by It will be done.

The input conditions u~ of the AND circuits 40CU1~41BP2
(5) Inputs (2) to (2) are constantly satisfied, and the input (2) is satisfied in accordance with the suppression of the key.

For example, if the key of the C note in the first octave U0 of the upper keyboard is pressed, the key switch KC□ of the keyboard circuit 1 closes, and the pitch name pulse φC of the C note is output from the 10th column line OL□ of the same circuit. be done.

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, AND circuits 40 CU and 41 CUl corresponding to the C key of the first octave U□ of the upper keyboard (also the AND circuit 41 CUl), but for convenience of explanation, only the 4-foot note will be considered.

) is applied to the input side from the column line OL□.

This pitch name pulse φC is applied to the decoder 23 or the Ramo AND circuit 40CU□, and is generated as shown in FIG. 5a when the time scale is reduced from that in FIG. 3.

Also, the octave pulse φU7 of the first octave U0 of the upper keyboard as shown in FIG.
This octave pulse serves to temporally allocate the note pulse to each octave.

Therefore, in AND circuit 40CU, octave pulse φU
One pitch name pulse φC is selected each time □ occurs.

Furthermore, a square wave frequency signal of the C tone at the height of the first octave U1 of the upper keyboard from the oscillator 31C is added to the AND circuit 40CU as shown in FIG. As shown in FIG. 5d, a pitch name pulse φU matching the generation timing of the octave pulse φU□ is periodically selected and outputted from the AND circuit 40CU□ every half period of the waveform resulting in a level).

If the main clock φ□ is 5 MHz, the frequency of the octave pulse φU0 is approximately 5000÷12÷10×40 kl (z), and the octave pulse φU.

The frequency of the pitch name pulse φC selected in synchronization with 1440k
The frequency is approximately Hz, which is higher than the audible frequency.

On the other hand, the square wave frequency of sound C is up to 2093Hz.
In terms of degree, about 10 pitch name pulses φC are selectively outputted during a half cycle as shown in the figure.

The other AND circuits 40CU2 to 41BP2 also operate in the same manner as described above.

Here, each AND circuit is 40 CU. ~41BP2, pitch name pulses φC~φB are selected for each octave type with a temporal shift by octave pulses φU0~φP2, so all AND circuits 40CU□~41
It is impossible for the time slots of the pitch name pulses φC to φB selectively outputted from BP2 to coincide.

That is, for different pitch names, pitch name pulses φC to φB
Since they are originally different, the time slots will never match, but if the octave types U□-P2 are different and the pitch name C-B is the same, the time slots will generally match.

If the time slots match in this way, 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 according to the square wave frequency of the same note name 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 will be generated. If the time slots of 2 and 2 match, a disadvantage arises in that only low frequency components are output from the OR circuit.

Therefore, in this invention, the octave pulse φU□~φP
2, the pitch name pulses φC to φB are selected in a temporally shifted manner for each octave type, and the pitch name pulses φC to φ are periodically selected according to each square wave frequency.
This is done so that the time slots of B do not match.

Therefore, each AND circuit is 40 CU. The outputs of ~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, the outputs of the AND circuits 40CU1 to 40BP2, 41CU, and 41BP2 are grouped by keyboard type.

Upper keyboard U0 in AND circuit 40CU, ~40BP2
~The outputs of the AND circuits corresponding to U4 are respectively OR circuits 42
, and the upper keyboard tone tJ K 4' for 4 feet is compositely output.

In the AND circuits 40CU and 40BP2, the outputs of the AND circuits corresponding to the lower keyboards L1 to L4 are respectively input to the OR circuit 44, and the outputs of the AND circuits corresponding to the lower keyboards L1 to L4 are inputted to the OR circuits 44, respectively, and the outputs of the AND circuits corresponding to the lower keyboards L1 to L4 are input to the OR circuits 44, respectively, and the lower keyboard L K 4'
is output as a composite.

In the AND circuits 40CU and ~40BP2, the outputs of the AND circuits corresponding to the pedal keyboards P□ to P2 are respectively input to the OR circuit 46, and the outputs of the AND circuits corresponding to the pedal keyboards P□ to P2 are respectively input to the OR circuit 46, and the pedal keyboard tone PK for 4 feet is
4' is compositely output.

In addition, the outputs of the circuits corresponding to the upper keyboard, lower keyboard, or pedal keyboard are also applied to the AND circuits 41C01 to 418P2, respectively, to the OR circuits 43, 45, and 47, and 8 feet from the OR circuits 43, 45, and 47. Composite tones UK8' to PK8' of the upper keyboard, lower keyboard, and pedal keyboard are output, respectively.

In FIG. 2, the connection manner of the input terminals of the OR circuits 42 to 470 is illustrated in the same manner as in the case of the AND circuits 40CU□ to 41BP2.

For example, if the keys of the C note in the first octave U0 and the C note in the second octave U2 of the upper keyboard are pressed at the same time, the oscillator 31C and the 1 frequency divider OD, the square wave frequency of the duck is shown in Figure 6a. , t), so the AND circuit 4
Outputs as shown in c and d of the figure are generated from 0CU□ and 40CU2.

Although the time scale of FIG. 6 is smaller than that of FIG. 5, the intervals of the selected note name pulses φC are not shown in proportion to that of FIG.

As is clear from the figure, the pitch name pulse φC is selected intermittently at a period T1. T2 is the cycle of musical tone frequency T1. T2
is consistent with

The output of AND circuits 40CU, 40CU2 is OR circuit 4
2, and the OR circuit 42 outputs a composite signal as shown in FIG. 6e.

This composite signal 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.

The signals UK4' to P which are composited in the form of coarse and fine pulses in this way
K8' is output from each of the OR circuits 42 to 47, and is supplied to the subsequent circuit as an output musical tone signal of the digital IC section 2.

As shown in FIG. 7, the output composite signal U of the digital IC section 2
K4'-PK8' are applied to clock removal filters 51 to 56 to remove high frequency (above audible frequency) tone frequency components and extract only musical tone frequency (square wave frequency) components.

The filters 51 to 56 can be configured, for example, by low-pass filters having a cutoff frequency at a high frequency that is an inaudible frequency.

The clock component of the composite signal shown in FIG. 6e is removed by a filter 51 to obtain an audio frequency signal component in which the level of the dense pulse portion is high and the level of the coarse pulse portion is low, as shown in FIG. 6f.

This audible frequency signal component is almost the same as the waveform obtained by analogically superimposing the waveforms shown in FIGS. 6a and 6b, and it can be seen that a waveform obtained by substantially superimposing musical tone frequencies was obtained.

The outputs of the clock removal filters 51-56 are applied to 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 resistors R1, R2 or R3, R4 or R5, R,
The frequency levels of the 4-foot sound and the 8-foot sound are added for each keyboard through the 8-foot filter 62.
, 64°66, this is because a staircase waveform containing many harmonic components is formed.

The outputs of the timbre control filters 61 to 66 are individually adjusted in volume by volume adjustment resistors 71 to 76, respectively, and then outputted through the audio system 80.

In the examples shown in FIGS. 2 and 7, the digital IC section 2
In the above, six OR circuits 42 to 47 were used, and the number of output connection pins was six, but if the timbre, volume, etc. were controlled in common for all keys, the number of output connection pins would be further reduced. .

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 41CU1 to 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 embodiment, the counter section 20 can also be configured by a ring counter such as a shift register, and can also be configured by the key switch arrangement of the keyboard circuit 1 or the sound source oscillation section 30.
The configuration is also 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, the keyboard circuit 1 receives note name pulses φC to φB.
I tried to input it, but the octave/response φU1~
It may be configured to input φP2.

In this case, the line OL□ corresponding to the octave type ~
0L1o is regarded as a row line, and this row line OL.

Octave pulses φU1~φ corresponding to ~0L1o, respectively
Input U2 separately.

Then, each note name may be regarded as a corresponding through line IL, -IL1Δ column line, and outputs (octave pulses) may be derived from the column lines ①L1 to ①L12 in accordance with the suppression of the key.

Therefore, the AND circuit 40CU1 in the digital IC section 2
The input end connection mode of ~41BP2 is also different from that in FIG.

That is, the outputs of column lines IL□ to IL1□ of each note name are output from AND circuits 40CU and 41B corresponding to the same note name, respectively.
Becomes the sole strength of P2.

Since the output timings of these column lines IL, ~lL12 have already been distinguished by octave type, the octave pulses φU1 ~ φP2, which are the outputs of the decoder 24,
It is no longer necessary to input the AND circuits 40CUI to 41BP2, and the inputs of the AND circuits 40CU□ to 40BP2 are the sound source oscillator 30 signal, the pitch name pulses φC to φB from the decoder unit 23, and the column line IL of the keyboard circuit 1.

~ IL, output of □ can be done without reducing the power of 3 people.

As explained above, according to the present invention, high-speed clock pulses are periodically (
Since the musical tone frequency signal is obtained based on the selected pulse (intermittently), all signal processing for selecting the frequency signal corresponding to the pressed key can be performed digitally. This method has the advantage that it is extremely easy to integrate the circuit into an IC, and that the S/N ratio of the musical tone signal obtained by selection is much better than that of conventional analog selection processing.

In addition, since the number of connection wires led to the keyboard circuit is greatly reduced, the number of connection pins can be reduced when converting the circuit to an IC.Furthermore, it is possible to completely convert the circuit into a digital IC, allowing for a more compact device. The aim is to promote the development of new products and reduce manufacturing costs.

[Brief explanation of drawings]

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 HALS. , FIG. 4 is a diagram explaining the input terminal connection function of the AND circuit in FIG. 2, FIG. 5 is a timing chart showing an input/output example of the section in FIG. 2, and FIG. 7 is a block diagram showing an example of the analog processing system in the embodiment of FIG. 1; FIG. 8 is an abbreviated block diagram showing an example of a modification of a part of FIG. 2. It is. 1...Keyboard circuit, 2-...Digital IC
Section, 20--Counter section, 30--Sound source oscillation section, 31C~31B--Oscillator, 32C~
32B --- Frequency divider circuit, OD1 to OD4 ---
Child frequency divider, 40...Digital gate section, 4
0CU1~40BP2.41CU1~41BP2...
---AND circuit, 42-49 ---OR circuit, 8
0...--Audio system.

Claims (1)

[Claims] A device that sequentially generates note name pulses occupying different time slots for each note name within 11 octaves, and a device that occupies a different time slot for each octave type, and each time slot corresponds to the note name pulse l octa-7 minutes. A device that sequentially generates octave pulses corresponding to a time width of a keyboard matrix circuit that inputs either the pitch name pulse or the octave pulse and derives an output from the column line according to the suppression of the key, and a sound source oscillation unit that generates frequency signals corresponding to the pitch of each weight, respectively; a plurality of AND circuits provided corresponding to each weight, each inputting the output from the column line of the keyboard matrix circuit corresponding to each weight, the note name pulse, the octave pulse, and the frequency signal; An electronic musical instrument that obtains a musical sound waveform based on the output of the AND circuit.