JPH0782338B2 - Electronic musical instrument - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic musical instrument called a so-called sampling keyboard or sampler which inputs various sounds such as musical instrument sounds and human voice sounds and outputs the sounds as desired pitches. It is about.

2. Description of the Related Art In recent years, semiconductors, in particular, memory technology has advanced, and a large amount of memory can be used at low cost. Against this background, many manufacturers have commercialized electronic musical instruments generally called sampling keyboards or samplers. Such an electronic musical instrument can be used in such a manner that a sound arbitrarily selected by the user is recorded and reproduced as sounds of various pitches. In other words, in a so-called keyboard instrument, it is an electronic musical instrument that allows a user to play a sound recorded by himself / herself as the tone color of the keyboard instrument so as to instruct the tone color of a piano or a guitar.

As a technique disclosed by using a computer, for example, a document “Journal of
The Audio Engineering Society "(Journal of the Autio Engineering Society, JAE
S. Volume 15, Number 1 January 1967 page 43-50)
There is.

As such an electronic musical instrument using a keyboard, there is Fairlight CMI manufactured by Fairlight Company.

(AUSTRALIA, Fairlight Instruments Pty. Ltd.Fairlig
ht CMI-Ready Reference Guide) The following is an overview of sampling keyboards. "Classification of high-tech instruments" (by Shunichi Furuyama)
Music Trade Magazine January 1985 Page 38-43
Published by Music Trade Co., Ltd.) The above electronic musical instrument will be described below with reference to the drawings.

FIG. 5 shows the configuration of the electronic musical instrument described above.

In FIG. 5, reference numeral 1 denotes an AD that converts an analog signal into a digital signal having a word length of m bits (hereinafter referred to as AD conversion).
A conversion unit 2, a memory for storing and outputting a m-bit word-length digital signal, and 3 a DA conversion unit for converting an m-bit word-length digital signal into an analog signal (hereinafter referred to as DA conversion), 4 Reference numerals 5 and 5 are first and second clock generators for generating clocks, 6 is a multiplier, 7 is a control unit, and 9 is an input unit for inputting an instruction regarding AD conversion or DA conversion, that is, recording or reproduction.

The operation of the electronic musical instrument configured as described above will be described below.

First, when the input unit 8 is instructed to perform AD conversion, that is, recording, the input unit 8 outputs a signal instructing the control unit 7 to start AD conversion.
The control unit 7 outputs a clock generation start signal for AD conversion to the first clock generation unit 4 and also outputs an address signal indicating the memory address “0” to the memory 2. After the clock generation start signal for the AD conversion is input, the first clock generation unit 4 outputs an AD conversion clock signal of a constant cycle, so-called sampling clock, to the AD conversion unit 1 and the control unit 7. The AD converter 1 converts the input analog signal into a digital signal at each sampling clock,
Generally, it is composed of a reduction pass filter, a sample hold, and an AD converter for satisfying the sampling theorem. AD
The conversion unit 1 receives the AD conversion clock signal every time it is input,
The input analog signal is converted into a digital signal and output to the memory 2. On the other hand, the control unit 7
When the AD conversion clock signal is input, a write signal is output to the memory 2 and then an address signal that increments the memory address by 1 is output. That is, the memory address is the first address. The memory 2 writes or stores the digital signal input from the AD converter 1 at a memory address corresponding to the address signal input from the controller 7 in accordance with the timing of the write signal. Eventually, the AD-converted digital signal is first stored in the memory address “0” of the memory 2. The control unit 7 outputs a clock generation stop signal for AD conversion completion, that is, AD conversion when the memory address indicated by the output address signal becomes larger than the maximum memory address storable in the memory 2. When the memory address indicated by the signal is not larger than the maximum storable memory address of the memory 2, the above operation is repeated. The first clock generator 4 is the AD
When the clock generation stop signal for conversion is input, the above AD
Stops conversion clock output. By the above operation,
The analog signal input to the AD conversion unit 1 after the AD conversion is started is a digital signal for each cycle of the AD conversion clock signal output from the first clock generation unit 4 from the memory address “0” (zero) of the memory 2. All the memory addresses that can be sequentially stored will be stored.

Next, when DA conversion, that is, an output musical tone is instructed to the input unit 8, the input unit 8 outputs a musical tone information signal regarding the pitch and strength (hereinafter referred to as touch) of the instructed output musical tone. When the musical tone information signal is inputted, the control unit 7
The clock generation unit 5 outputs a time period signal for generating a clock signal having a time period proportional to the pitch of the instructed output musical tone and a clock generation start signal for DA conversion, and stores it in the memory 2. An address signal indicating the address "0" is output, and the multiplication value corresponding to the touch of the instructed output tone is output to the multiplier 6. After the clock generation signal for the DA conversion is input, the second clock generation unit 5 outputs the DA conversion clock signal of a time period according to the time period signal, that is, a so-called sampling clock, to the control unit 7.
And output to the DA converter 3.

When the DA conversion clock signal is input, the control unit 7 outputs a read signal to the memory 2 and then outputs an address signal that increments the memory address by one. That is, the memory address is the first address. The memory 2 reads the digital signal at the memory address corresponding to the address signal input from the control unit 7 according to the timing of the read signal and outputs it. When the memory address indicated by the output address signal becomes larger than the maximum storable memory address of the memory 2, the control unit 7 outputs the clock generation stop signal for ending the DA conversion, that is, the DA conversion. When the memory address indicated by the signal is not larger than the maximum storable memory address of the memory 2, the above operation is repeated.

On the other hand, the digital signal output from the memory 2 is multiplied by a multiplier value corresponding to the touch of the output musical tone instructed in the multiplier 6, and then output to the DA conversion unit 3. The multiplier 6 also operates at each timing of the DA conversion clock signal.

The DA conversion unit 3 generally includes a latch for holding a digital signal and a DA.
It is made up of a converter and a low-pass filter that removes aliasing frequency components.The digital signal updated every sampling clock is held by the latch, and the held digital signal is converted to an analog signal by the DA converter. After that, the aliasing frequency component is removed by the low pass filter.

The DA converter 3 converts the digital signal output from the multiplier 6 into an analog signal at a timing according to the DA conversion clock signal and outputs the analog signal as a tone signal.

The second clock generator 5 stops the output of the DA conversion clock when the clock stop signal for the DA conversion is input. By the above operation, after the DA conversion is started, all the digital signals stored in the memory 2 are sequentially converted from the digital signals stored in the memory address 0 to the DA converted clock signal output from the second clock generator 5. After being output every cycle, the multiplier 6 performs multiplication according to the touch, and the DA converter 3 outputs the analog signal, that is, a tone signal.

In the above DA conversion operation, when the input unit 8 is instructed to stop the output of the musical sound, the input unit 8 outputs the musical sound output stop signal to the control unit 7. When the musical sound output stop signal is input, the control unit 7 outputs the clock generation stop signal for the DA conversion, and ends the DA conversion. In the above description, one musical tone is output, but in order to realize simultaneous output of a plurality of tones k, which is so-called polyphonic in an actual electronic musical instrument, the input unit 8, the control unit 7, and the second clock generation unit 5 are used.
The memory 2 is provided with k DA converters 3 and k multipliers 6 each.
There is an electronic musical instrument in which the digital signal stored in is read out by time division processing and k sounds are simultaneously output.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-described configuration, when it is desired to output an analog signal of an input to be recorded as a musical tone having a different sound quality, the digital signal output from the memory 2 is processed by arithmetic processing, or Since the analog signal output from the DA converter 3 must be configured to be filtered, it is a channel for high-speed processing or compounding that is required for time-division multiplexing of the reproduction process and outputting compound sounds. There was a problem of economic efficiency that the number of processing units had to be increased.

In view of the above problems, the present invention provides an electronic musical instrument capable of arbitrarily implementing sound quality processing of recording input and reducing the time load of reproduction processing.

Means for Solving the Problems In order to achieve this object, an electronic musical instrument of the present invention is provided with a signal processing instruction input section for instructing and inputting processing of a digital signal, and converting an input analog signal into a digital signal and outputting it. An AD conversion unit, a memory capable of writing and reading digital signals, and a digital signal output from the AD conversion unit is processed into a signal corresponding to the input from the signal processing instruction input unit and output to the memory. It is composed of a signal processing unit.

Operation With this configuration, the input analog signal is converted into a digital signal in the AD conversion unit and output. The signal processing unit performs predetermined conversion on the digital signal output from the AD conversion unit and then outputs the digital signal. The digital signal output from the signal processing unit is stored in the memory.

The signal processing instruction input unit controls the input / output characteristics of the signal processing unit by outputting to the signal processing unit an output corresponding to an input input relating to the input / output characteristics of the signal processing unit.

With the above operation, the AD-converted digital signal is stored in the memory after being subjected to conversion processing for sound quality processing in the signal processing unit.

Embodiment One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the structure of an electronic musical instrument according to an embodiment of the present invention. In FIG. 1, reference numeral 10 is a signal processing instruction input unit that outputs an output corresponding to an input instruction regarding input / output characteristics of the signal processing unit, which is arbitrarily input, to the signal processing unit, and 11 is an AD.
It is a signal processing unit for converting the digital signal output from the conversion unit 12 in accordance with the input / output characteristic instruction output from the signal processing instruction input unit 10.

1 is an AD conversion unit, 2 is a memory, 3 is a DA conversion unit, 4 and 5 are first and second clock generation units, 7 is a control unit, and 8 is an input unit. Are the same.

The operation of the embodiment configured as described above will be described below.

First, desired input / output characteristics are input to the signal processing instruction input unit 10. Although various forms can be considered as the input form, in the present embodiment, the input / output characteristics are numerically input as a polygonal line approximation. A keyboard (terminal), for example, can be used as such a signal processing instruction input unit.

For example, to input the input / output characteristics as shown in FIG. 2, the start coordinates and the break point coordinates are (−M, −M) and (M−1,
Enter as M-1). In addition, the origin is the break point (-
Even if input as M, -M), (0, 0), (M-1, M-1), the same characteristics are obtained. Here, M is a predetermined constant, and the word length of the digital signal input / output in each part is m bits. When the numerical value is to be displayed in 2's complement, the following relational expression is obtained. .

M = 2 ^(m-1) (1) The signal processing instruction input unit 10 outputs the input coordinates.
The signal processing unit 11 performs the numerical conversion processing corresponding to the coordinates output from the signal processing instruction input unit 10 to convert the input m-bit word length digital signal into an m-bit word length digital signal. Give. For example, a numerical range in which a digital signal having a word length of m bits, which is input by sequentially linearly interpolating the input start coordinates and break point coordinates, can be expressed, that is, -M,-(M-1),-( M-2),
.., (M-2), (M-1), a digital signal having a word length of m bits output corresponding to each numerical value is obtained. Linear interpolation can be realized as follows.
First, the two coordinates to be linearly interpolated are (x ₁ , y ₁ ) and (x ₂ ,
We obtain the following equation as y ₂ ).

However, a and b are unknown numbers.

From equation (2), a and b are determined as follows.

However, when x ₁ = x ₂ Therefore, we obtain the following equation that implements linear interpolation.

y≈ax + b (5) However, x is an input numerical value and y is an output numerical value, both of which are integer values.

In the equation (5), the value of the input numerical value x is changed as an integer value from x ₁ to x ₂ to obtain the output numerical value y.

The signal processing unit 11 calculates the m-bit word-length digital signal, that is, the output numerical value y according to the equation (5), using the input numerical value x of the m-bit digital signal of the word length as the input numerical value x. However, since it takes a calculation processing time to sequentially perform the above-described calculation processing on the input digital signal, the calculation processing of the linear interpolation as described above is performed in advance when the coordinates are input. It is preferable to use a so-called table lookup system in which the calculated results of the input / output characteristics are stored as a table and the output numerical value can be determined only by referring to the table corresponding to the numerical value of the input digital signal. Further, the signal processing unit 11 sequentially performs the above-described signal conversion processing operation on each input digital signal in accordance with the timing of the AD conversion clock supplied from the first clock generation unit 4. .

With respect to the signal processing unit 11 that operates as described above, the digital signal output from the AD conversion unit 1 with the same configuration and operation as the conventional example is subjected to signal processing processing in the signal processing unit 11 and then stored in the memory. Will be stored in 2.

When the linear conversion as shown in FIG. 2 is performed, the signal processing unit 11 having the input / output characteristics outputs the input as it is without performing the sound quality processing.

Since the signal processing section 11 having a polygonal input / output characteristic as shown in FIG. 3 performs non-linear compression, it works to increase the power of the signal especially for percussive sounds such as piano and cymbals.

The signal processing unit 11 having discontinuous input / output characteristics as shown in FIG. 4 carries out an example of sound quality processing.

In the above, the input characteristic of the signal processing unit 11 is the polygonal line approximation based on polygonal coordinate input and linear interpolation thereof, but the method of determining the input / output characteristic is not limited to this, and the polygonal line is used. It should be added that it is possible to use a curve instead of the above, or to input the correspondence of all coordinate spaces.

As described above, according to this embodiment, the signal processing unit 11 processes the digital signal output from the AD conversion unit 1,
In addition, since the digital signal which has been subjected to signal processing is stored in the memory 2, at the time of reproduction, it suffices to simply read out from the memory 2 the digital signal which has already been subjected to sound quality processing (signal processing). The processing can be performed at the processing speed, and the reproduction processing can be performed in the conventional manner even when a compound sound is generated. Furthermore, since the signal processing is also performed as the numerical conversion for the recording processing, it is possible to reduce the time required for the processing processing. Also, the signal processing instruction input section
By providing 10, it is possible to instruct and implement arbitrary sound quality processing. Further, the power of the input signal can be increased by appropriately setting the input / output characteristics of the signal processing unit 11.

EFFECTS OF THE INVENTION According to the present invention, the sound signal is processed by processing the digital signal output from the AD conversion unit in the signal processing unit, and the processed digital signal is stored in the memory. It is possible to output the sound whose sound quality has been processed simply by performing the conventional operation of reading. Further, since the sound quality processing is carried out at the time of recording in this way, it is possible to eliminate the cost increase for producing a double sound at the time of reproduction.

Furthermore, by allowing the signal processing instruction input unit to arbitrarily set the input / output characteristics of the signal processing unit, arbitrary sound quality processing can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an electronic musical instrument according to an embodiment of the present invention, FIGS. 2 to 4 are exemplary input / output characteristic diagrams of a signal processing unit according to the present invention, and FIG. FIG. 3 is a block diagram of an electronic musical instrument in the related art. 1 ... AD converter, 2 ... memory, 10 ... signal processing instruction input section, 11 ... signal processing section.

Claims (1)

[Claims] 1. An electronic musical instrument that records various sounds and reproduces them as desired pitches, and an AD converter that converts an analog signal of the sounds to be recorded into a digital signal having a word length of n bits according to a predetermined clock. , A word-length n-bit digital signal is converted into a word-length m bit (n>
m) a signal processing unit for converting into a digital signal, a memory for storing the word-length m-bit digital signal, a signal processing instruction input unit for inputting conversion characteristics in the signal processing unit, and a memory for storing in the memory. An electronic musical instrument configured to reproduce a desired pitch tone from a digital signal having a word length of m bits, wherein the signal processing in the signal processing unit is table lookup conversion (numerical conversion).