JPH0760311B2 - 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 Audio Engineering Society, JAE
S.Volume 15, Number 1 January 1967 pages 43 to 50).

As such an electronic musical instrument using a keyboard, there is Fairlight CMI manufactured by Fairlight Company. (AUSTRALIA, Fu
irlight Instruments Pty. Ltd.Fairlight CMI-Read
y Reference Guide) The following is an overview of sampling keyboards.

"Classification of high-tech instruments" Shunichi Furuyama, Music Trade Magazine, January 1985, pages 38-43, published by Music Trade Co., Ltd.).

Hereinafter, the electronic musical instrument will be described with reference to the drawings.

FIG. 3 shows the configuration of the electronic musical instrument described above.

In FIG. 3, 1 is an AD converter that converts an analog signal into a digital signal (hereinafter referred to as AD conversion), 2 is a memory that stores and outputs the digital signal, and 3 is a digital signal that is converted into an analog signal (hereinafter referred to as DA conversion). DA converter to call 4) 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 outputs an address signal indicating the memory address 0 to the memory 25. 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 conversion unit 1 converts an input analog signal into a digital signal at each sampling clock, but is generally made up of a low pass filter, a sample hold, and an AD converter for satisfying the sampling theorem. Each time the AD conversion clock signal is input, the AD conversion unit 1 converts the input analog signal into a digital signal and outputs it to the memory 2. On the other hand, the control unit 7 uses the AD
When the converted clock signal is input, a write signal is output to the memory 2 and then an address signal that increases the memory address by "1" is output. That is, the memory address is "1"
It becomes the 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 the clock generation stop signal for AD conversion completion, that is, for AD conversion when the memory address indicated by the output address signal becomes larger than the maximum value of the memorable memory address of the memory 2.
When the memory address indicated by the address 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
When the clock generation stop signal for AD conversion is input,
Stops AD 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 memory address “0” of the memory 2 as a digital signal for each cycle of the AD conversion clock signal output from the first clock generation unit 4. All the memory addresses that can be stored are sequentially stored from the address.

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 a multiplier 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 controls the DA conversion clock signal of time period, so-called sampling clock, according to the time period signal.
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 for increasing the memory address by "1". That is, the memory address is the address "1". 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 components are 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 output from the second clock generator 5 from the digital signal stored in the memory address “0”. After being output in each signal cycle, the multiplier 6 performs multiplication according to the touch, and the DA converter 3 outputs the analog signal, that is, a tone signal.

During the above DA conversion operation, when the input section 8 is instructed to stop the musical sound output, the input section 8 outputs a musical sound output stop signal to the control section 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.

The pitch of the input analog signal for AD conversion and the pitch of the output analog signal obtained by DA conversion are Na and Nd [Hz], respectively.
The conversion clocks for conversion and DA conversion are Ta and Td, respectively.
[SEC] gives the following relational expression.

Therefore, the input analog signal with a pitch of Na [Hz] is Nd
It will be output as an output analog signal with a pitch of [Hz].

By preparing a plurality of sets of the above configuration, an electronic musical instrument that simultaneously outputs a plurality of types or a plurality of pitched musical tones is configured.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-mentioned configuration, the pitch Na [Hz] of the input analog signal to be recorded is different from the pitch of the normal scale tone, that is, the tuning is shifted. In this case, in order to reproduce the pitch Nd [Hz] of the output analog signal to be reproduced as the pitch of a normal scale tone, tuning is performed by arbitrarily adjusting the clock time period Ta [Hz] during AD conversion. I had to do it. This is AD
Not only does the conversion or recording operation have to be repeated, but it also means that the signal to be recorded must use a reproducible sound source such as a tape recorder or a record. That is, there is a problem that tuning cannot be performed when directly converting the sound of a musical instrument such as a trumpet whose sound changes each time.

In view of the above problems, the present invention provides an electronic musical instrument that can be tuned by only one AD conversion.

Means for Solving the Problems In order to achieve this object, the electronic musical instrument of the present invention has an AD conversion unit for converting an input analog signal into a digital signal,
An input memory for storing a digital signal output from the AD conversion unit, and a digital signal stored in the input memory corresponding to an instruction input regarding processing of the digital signal, and the processed digital signal It is composed of a processing control section for outputting, an output memory for storing the processed digital signal output by the processing control section, and a DA conversion section for converting the digital signal in the output memory into an analog signal. .

Operation With this configuration, the digital signal output from the AD conversion unit and stored in the input memory is processed by the processing control unit and then processed, that is, tuned and output. The processed digital signal output from the processing control unit is stored in the output memory, so during DA conversion, the digital signal stored in the output memory is read and converted to an analog signal in the DA conversion unit as in the conventional example. Only by converting, an analog signal with a processed or tuned pitch will be obtained. If the processed digital signal is still out of tuning, change the instruction input related to the processing that was instructed to the processing control section and immediately perform processing again on the digital signal stored in the input memory. By doing so, the tuned digital signal is stored in the output memory.

Examples Hereinafter, one example of the present invention will be described 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 denotes an input memory for storing the digital signal AD-converted by the AD converter 1.
Reference numeral 12 is a processing control unit that reads the digital signal stored in the input memory 10 and outputs the processed digital signal after performing processing corresponding to the instruction input, and 11 is a memory that stores the processed digital signal.

1 is an AD converter, 3 is a DA converter, 4 and 5 are first and second clock generators respectively, 6 is a multiplier, 7 is a controller, and 8 is an input unit. It has the same structure.

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

First, when the input unit 8 is instructed to perform AD conversion, that is, recording, the AD conversion unit 1, the first clock generation unit 4, the control unit 7, and the input unit 8 are input to the input memory 10 by the same operation as in the conventional example. The digital signal obtained by converting the analog signal is stored. At this time, the input memory 10 is the memory 2 shown in the conventional example.
The same operation as.

The processing control unit 12 performs the following operation in order to process the digital signal based on the input pitch ratio r.

First, after reading the digital signal at the memory address “0” of the input memory 10, this is read by the output memory 11
It is stored in the memory address “0” of.

The digital signal Y _i to be stored at the memory address i in the output memory 11 can be obtained as follows.

If a value R is obtained by multiplying the pitch ratio r by i, the maximum integer value j smaller than R is obtained. Next, the digital signals X _j and X stored in the memory address j of the input memory 10 and (j + 1) are stored.
By reading out _{j + 1} and performing the operation of the following equation, Y _i
Can be obtained.

Y _i = X _j + (X _{j + 1} −X _j ) (R−j) (1) The digital signal Y _i to be stored at the memory address i in the output memory 11 obtained as above is stored. The processing control unit 12 for sequentially storing in the output memory 11 operates when either i or (j + 1) becomes equal to the maximum storable address in the output memory 11 or the input memory 10, respectively. To finish.

By reading the digital signal from the output memory 11 storing the processed digital signal Y _i , the DA converter 3 and the second
The clock generation unit 5, the multiplier 6, the control unit 7, and the input unit 8 perform the DA conversion in the same operation as in the conventional example.

FIG. 2 shows digital signals stored in the input memory 10 and the output memory 11. FIG. 2a shows an input memory 10
2b shows the digital signal stored in FIG. 2, and FIG. 2b shows the digital signal stored in the output memory 11. FIG. 2B is an example in which the processing for r = 1.5 is performed on the digital signal of FIG.

In the present embodiment, the calculation for processing the digital signal is linear interpolation using the formula (1), but this may be higher order interpolation.

As described above, according to the present embodiment, the memory has two memory configurations, the input memory 10 for AD conversion and the output memory 11 for DA conversion, and the digital signal of the input memory 10 is output. When the data is transferred to the memory 11, the processing control unit 12 performs processing (pitch conversion). Therefore, when the pitch of the musical tone output by DA conversion is unsatisfactory, the processing instruction to the processing control unit 12 ( Tuning can be performed by changing the pitch conversion instruction. Furthermore, since the processing (pitch conversion) is realized without changing the contents of the output memory 11, the AD conversion operation only needs to be performed once.

EFFECTS OF THE INVENTION The present invention uses an input memory that stores AD-converted signals,
When the signal is transferred to the output memory, the processing control unit performs signal processing (pitch conversion) processing on the transfer signal, so the signal in the input memory obtained by AD conversion once It is possible to provide an electronic musical instrument that can be tuned by repeating signal processing (pitch conversion) as many times as possible without destroying the.

[Brief description of drawings]

FIG. 1 is a block diagram of an electronic musical instrument according to an embodiment of the present invention, FIG. 2 is an exemplary signal diagram of signals before and after processing of signal processing (pitch conversion) according to the present invention, and FIG. It is a block diagram of the electronic musical instrument in a prior art. 1 ... AD converter, 3 ... DA converter, 10 ... input memory, 11 ... output memory, 12 ... machining controller.

Claims (1)

[Claims] 1. An electronic musical instrument that records various sounds and reproduces them as desired pitches, and an AD conversion unit that converts into digital signals according to a predetermined clock irrespective of the cycle of analog signals of the sounds to be recorded. An input memory for storing the digital signal output from the AD conversion unit, an output memory for storing the digital signal, and a DA conversion unit for converting the digital signal output from the output memory into an analog signal. An electronic musical instrument comprising a processing control section for storing, in the output memory, a digital signal which has been subjected to pitch processing instructed with respect to the digital signal stored in the input memory.