JPS581440B2 - 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 frequencies corresponding to the pitches of each key on a keyboard.

Conventionally, electronic musical instruments are equipped with a sound source that oscillates at a frequency corresponding to the pitch of each key on the keyboard, and the required frequency signal is selected from the sound source in response to the key presses. 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 the patent application No. 49-146048 titled "Electronic musical instrument," the number of connection lines between the keyboard circuit and other circuits was 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. Further improvements are desirable for complete digital IC implementation.

This invention was made in view of the above circumstances, and is configured so that all the sound source circuits connected to the keyboard circuit can be processed digitally, making it easy to integrate them into ICs, and eliminating the wiring from the keyboard circuit. The goal is to simplify the design and reduce the number of connection pins when integrated into an IC.

For this purpose, in the present invention, each key switch in a keyboard circuit is arranged in a matrix consisting of a row corresponding to each note name (12 scale notes) within one octave and a column representing the octave to which the note name (scale note) belongs. The pitch name pulses arranged in a circuit network and generated sequentially at high speed for each pitch name within one octave are input into the corresponding rows, and the pitch name pulses for the key are generated from the prearrangement according to the octave to which the pressed key belongs. It is configured to output.

In the sound source circuit section to which the matrix lines of this keyboard matrix circuit are connected, a square wave signal oscillated corresponding to the pitch frequency of each key, the note name pulse corresponding to the note name of the key, and the column line An AND circuit whose output is the input, periodically selects the pitch name pulse of the pressed key according to the pitch frequency of the pressed key, and generates a musical sound waveform based on the periodically selected high-speed pitch name pulse. It is characterized by being configured to obtain the following.

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 the pitch name pulses described above, and the digital gate section 40 periodically selects the pitch name pulse of the pressed key in accordance with the sound source 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 70, and then produced via an audio system 80.

FIG. 2 shows the main part of this invention, and the keyboard circuit 1 consists of row lines IL1 to ■L12 that designate each of the 12 note names C, C#, D...A#, B of each octave, and the corresponding notes. Name C-B
The type of octave to which each belongs (for example, the first octave U1 to fourth octave U4 of the upper keyboard, the first octave L1 to fourth octave L4 of the lower keyboard, and the first octave P1 and second octave P2 of the pedal keyboard) Column lines OL1 to OL1 representing
It is configured by a matrix circuit network having 0 and 0.

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 unit 20 has a hexadecimal pitch name counter 21 that sequentially counts high-speed clock pulses φ1 (for example, 1 MHz) as shown in FIG. 3a, and a decoder 22 that decodes the output of this pitch name counter 21. There is.

The counting output of the pitch name counter 21 is decoded into 12 outputs by the decoder 22, and pitch name pulses φC, φC#, φD, . . . φA#, φB as shown in FIG. 3B are sequentially generated.

Pitch name pulses φC to φB are 12 pitch names C within one octave.
-B, and these pulses are generated by sequentially circulating and occupying different time slots for each note name.

The pitch name pulses φC to φB are input to the row lines IL1 to IL12 of the corresponding pitch names in the keyboard circuit 1, respectively, and simultaneously control the on/off states of the key switches with the same pitch name in each octave U1 to P2 in the time slot. It is designed to be detected.

The sound source oscillator 30 generates each note C-B in the highest octave.
12 oscillators 31C, 31C each oscillating the frequency of
,... 31A#, 31B and the oscillation frequencies of each oscillator 31C to 31B are divided sequentially to obtain each note name C in each octave.
-12 sets of frequency divider circuits 32C that generate the frequency of B,
32C#, ...32A#, 32B (for convenience, the oscillators 31C, 31B and the frequency divider circuit 32 with pitch names C and B are included).
Only 0.32B is shown).

These oscillators 310 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 frequency dividing circuit 32C to 32B has a plurality of cascade-connected 1/1/2
It is composed of 2 frequency dividers OD1 to OD4.

The digital gate unit 40 includes a plurality of AND circuits 40CU1, 40CU2, . . . corresponding to each key (as many as the total number of keys).
40CP2,...40BU1,40BU2,...40B
It has P2.

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, 41CU2, 41CP2, 41
It includes BU1, 41BU2, . . . 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, FIG. 4 shows the connection mode using AND circuits 40CU1 and 41CU1 as an example in a normal manner.

Three inputs are added to each AND circuit 40DU1 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), ■ Output of the column line corresponding to the octave type to which the key belongs in the keyboard circuit 1 (one of OL1 to OL1o), 03 input to each AND circuit 40CU1 to 41BP2, respectively. Added.

For example, in the case of the AND circuit 40CU1, ■ the highest octave C frequency signal from the oscillator 31C at 4 feet, ■
The pitch name pulse φC of the note C, and the column line OL1 output of the first octave U1 of the upper keyboard are input, respectively.

In the case of the AND circuit 41CU1, the input of the above-mentioned ■■ is the same as the AND circuit 40CU1, but since the input is an 8-foot tone, the frequency obtained by dividing the output of the oscillator 31C of the C tone by one is added to the input of the input of the ■■.

The input conditions for AND circuits 40CU1 to 41BP2 -
Of (2), the input (2) is 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 U1 of the upper keyboard is pressed, the key switch KC1 of the keyboard circuit 1 is closed, and the pitch name pulse φC of the C note is output from the 10th column line OL1 of the same circuit. .

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, the AND circuit 40CU1 corresponding to the C key of the first octave U1 of the upper keyboard (this also applies to the AND circuit 41CU1, but for convenience of explanation, only the 4-foot note will be considered).

) is applied to the input side from the column line OL1.

This pitch name pulse φC is also applied to the AND circuit 40CU1 from the decoder 22, and is generated as shown in FIG. 5a when the time scale is reduced from that in FIG. 3.

In addition, 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 40CU1 as shown in FIG. ), the pitch name pulse φC is periodically output to the AND circuit 40 as shown in FIG. 5C.
It is selectively output from CU1.

If the main clock φ1 is IMHz, the frequency of the pitch name pulse φC is about 1000÷12≈80 kHz, and the frequency of the selected pitch name pulse φC is also about 80 kHz, 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 20 half-cycle pitch pulses φC
will be selectively output as shown.

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

Here, for each octave type, 12 pitch name pulses φC to φB are generated sequentially with a time lag, so the time slots of the output pulses of the AND circuit corresponding to keys with different pitch names are It does not match.

Therefore, each AND circuit 40CU1-4 for each octave type.
The outputs of 1BP2 can be combined into a common line using an OR circuit.

As shown in FIG. 2, each AND circuit 40CU1 to 40B
The output of P2,4 ICU1~41BP2 is OR1~ for each octave type U1~P2 and for each foot note 4', 8'.
They are respectively input to OR2o.

For example, AND circuits 40CU1, 40C#U1...40BU1 and 41C corresponding to the first octave U1 of the upper keyboard
The output of U1.41C#U1,...41BU1 is input to the OR circuit OR1 of the first octave of the 4-foot upper keyboard and the OR circuit OR of the first octave of the 8-foot upper keyboard, respectively. The same is true.

From each OR circuit OR1 to OR2o, the sound source signals of the 4-foot sound and the 8-foot sound of the 1st octave of the upper keyboard to the 2nd octave of the pedal keyboard are sent separately (for each octave type).
It is output as a composite.

In FIG. 2, the connection manner of the input terminals of the OR circuits OR1 to OR20 is illustrated in the same manner as that of the AND circuits 40CU1 to 41BP2.

The output of each OR circuit OR1 to OR20 is the digital IC section 2.
' is supplied to the clock removal filter 50 as an output.

As shown in FIG. 7, clock removal filters 501 to 52
0 is each octave type (each OR circuit OR1 to OR20)
The filters 501 to 5 are provided correspondingly to each other.
20 is constituted by, for example, a low-pass filter with a cutoff frequency of a high frequency that is an inaudible frequency, and is designed to remove a pitch name pulse component that is a high frequency component that is higher than an audible frequency and extract only the sound source frequency component. It has become.

Therefore, these clock removal filters 501 to 520 remove high-speed pitch name pulse components as shown in FIG. 5C,
A sound source frequency component as shown in b of the same figure is extracted.

Here, since the generation frequency of the pitch name pulses φC to φB is quite high (for example, 80 kHz), the pulses are generated extremely densely.

Therefore, there is an advantage that the level of the output pulses (waveforms shown in FIG. 5b) passing through the filters 501 to 520 can be made considerably large.

Therefore, the musical tone signal level is high, and the S/N ratio can be made quite good.

By the way, if two or more keys of the same octave type are pressed at the same time, the pulse output in the form of coarse and fine pulses will be output from the OR circuit O.
Obtained from R1 to OR20.

For example, when the C and B notes of the first octave U1 of the upper keyboard are pressed at the same time, the square wave frequencies from the oscillators 31C and 31B have a relationship as shown in a+b in FIG. Outputs as shown in c and d are produced.

Although the time scale of FIG. 6 is smaller than that of FIG. 5, the interval between the selected note name pulses φC and φB is the same as the fifth
The figures are not drawn to scale.

The outputs of the AND circuits 40CU, 40BU1 are both applied to the OR circuit OR1, but since the time slots of the pitch name pulses φC and φB are different, they are combined into a dense pulse signal as shown in FIG. 6e, and are combined into the OR circuit OR1. is output from.

The output of this OR circuit OR1 is applied to the clock removal filter 501 to remove the pitch pulse component, and as shown in FIG. Get the ingredients.

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 a waveform obtained by substantially superimposing and synthesizing the sound source frequencies is obtained.

In FIG. 7, the outputs of the clock removal filters 501 to 520 are output to the corresponding timbre control filters 601 to 620, respectively.
, and timbre control is performed for each octave type.

Note that the frequency signal levels of the 4-fort tone and 8-foot tone are added via resistors R1 and R2 for each octave type and input to the 8-foot tone control filter, but this is a high-frequency signal. This is because a staircase waveform containing many components is formed.

The sound output from each timbre control filter 601-620 is commonly applied to volume controllers 71-76 for each keyboard type,
The sound is produced through the audio system 80 after the volume is adjusted separately.

In Figure 7, timbre was controlled by octave type,
As shown in FIG. 8, the process may be performed for each type of keyboard.

That is, if the outputs of the clock removal filters 501-520 are commonly applied to the individual keyboard timbre control filters 61-66 for each type of keyboard via the resistor R3, the timbre can be controlled for each type of keyboard.

As explained above, according to the present invention, high-speed clock pulses are periodically (
Since the musical sound waveform is obtained based on the selected pulses (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, the above-mentioned high-speed clock pulse (
Only the pitch name pulses corresponding to the 12 pitch names C and B are used, and the octave type is identified by distinguishing the output lines, so the clock pulses (pitch name pulses) that are generated quite precisely Since a musical tone waveform can be formed and the signal level of the musical tone waveform can be increased, the S/N ratio can be further improved.

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. It is possible to promote this process and reduce manufacturing costs.

[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 end connection mode of the AND circuit in FIG. 2, FIG. 5 is a timing chart explaining the operation of each part in FIG. 2, and FIG. 6 is a diagram showing the relationship between FIGS. 2 and 7. FIG. 7 is a block diagram showing an example of the analog processing system in the embodiment of FIG. 1, and FIG. 8 is a block diagram showing another example of the same analog processing system. 1... Keyboard circuit, 2... Digital IC section, 20... Counter section, 30... Sound source oscillation section, 31C to 31B... Oscillator, 32C to 32B... Frequency dividing circuit, OD1 to OD4...
1 frequency divider, 40...Digital gate section, 40CU1-4
0BP2,41CU1~41BP2...AND circuit, 5
0,501-520...Clock removal filter, 60,
601-620.61-66...Tone control filter,
70.71-76...Volume adjuster, 80...Audio system.

Claims (1)

[Claims] 1. A device that sequentially generates note name pulses occupying different time slots for each note name within one octave, and a key switch for each key arranged and connected to a plurality of matrix lines corresponding to note names and octave types, A keyboard matrix circuit inputs the note name pulse corresponding to each row line and derives an output from the column line in response to a key press, and generates a frequency signal corresponding to the pitch of each key. a sound source oscillation section, which is provided corresponding to each key, and generates a pressed key based on the pitch name pulse corresponding to the pitch name of the key, the frequency signal corresponding to the key, and the output of the keyboard matrix circuit; and a plurality of AND circuits for periodically selectively outputting the pitch name pulse corresponding to the key according to the frequency signal corresponding to the key, based on the pitch name pulse periodically selected by the AND circuit. An electronic musical instrument that obtains musical sound waveforms using