JP2517529Y2 - Envelope extraction device - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] The invention relates to an envelope extracting device that extracts an envelope waveform from sampled sound waveform data.

[Background] Although the ability to synthesize sounds that sound like natural musical instruments is an important issue in electronic musical instruments, to date, there has been a considerable gap between electronically synthesized sounds and natural musical instrument sounds. ing. The sounds that can be synthesized electronically are deeply related to the limit of the processing capability of the current musical sound processing apparatus. The tone processor is
It does not have the ability to execute complex calculations in real time, and can perform only simple and low-degree of freedom processing. As a result, most of the features such as complicated tone color changes found in natural musical instrument sounds are lost.

For example, in the case of a device for synthesizing a musical tone by multiplying data for one waveform of the fundamental frequency of the musical tone by envelope data, it is not possible to generate an envelope waveform that changes in a complicated manner. Sectionally monotonic waveform (eg exponential curve)
Can only be generated and the only degree of freedom is changing the coordinates of the ends of the interval.

The sound making method that is done under the constraints of the current hardware and software accepts the constraint conditions,
Within a few degrees of freedom available, by trial and error,
Another approach is to create sounds artificially. This goes in a completely different direction from the original approach to natural instrument sounds.

On the other hand, as represented by a sampling instrument, there is also known a device that samples the waveform itself of a natural musical instrument sound by PCM and reads the sampled waveform data in real time to generate a sound. This type of device can faithfully reproduce sampled sounds. However, since it has musical tone information in the form of a completed waveform, it is not suitable for arithmetic processing, and features of natural musical instrument sounds that change intricately depending on the pitch and playing style can be created from sampled waveform data of one natural musical instrument sound. I can't. in short,
It can be said that the idea of electronically synthesizing sounds is basically abandoned in sampling instruments and the like.

In order to obtain a sound like a natural musical instrument sound by synthesizing this device, an approach such as performing data analysis on the natural musical instrument sound, extracting its characteristics, and obtaining a synthetic sound using the extracted characteristic parameters is effective. It was devised with the recognition that

[Purpose of the Invention] The purpose of the invention is to provide an envelope extraction device that extracts envelope data that preserves the characteristics of the original sound from sampled waveform data.

[Summary of the Invention] In order to achieve the above object, the present invention divides all waveform sections of sampled waveform data, and sums the squares of the respective values of the waveform data included in each of the divided small sections ( The main point is to calculate the power of the waveform) and determine the envelope value specific to the corresponding small section based on the calculation result.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the overall configuration of this embodiment. The musical tone data memory 1 stores sampled musical tone data, and this musical tone data is supplied to an envelope extraction circuit 2 where an envelope value is extracted in units of the period extraction section. The extracted envelope data is stored in the extraction envelope memory 3. Hardly,
The envelope extraction circuit 2 is composed of a keyboard, an input / output device such as a display, a memory for programs and work, a processor device, and the like.

FIG. 2 shows the configuration of the main part of the envelope extraction circuit 2. The extraction section setting scanning unit 21 receives the information from the input device and decides the section for extracting the envelope value one by one. Then, the entire section of the sampled musical sound data is scanned. In this example, sampling frequency information of musical sound data and musical sound (basic) frequency information are given as input information. Therefore, a section corresponding to the cycle of the sampled musical sound is selected as a section (extracting section) used to extract one envelope value.

The section tone data read-out unit 22 sequentially outputs the tone data included in the current section given by the extraction section setting scanning unit 21,
It is read from the tone data memory 1.

The sum of squares calculation unit 23 calculates the sum of squares (waveform power) of the respective values of the tone data in the section given by the reading unit 22, and the extraction section setting scanning section 21 notifies the completion of the current scanning section. Then, the calculated sum of squares is written to the memory position assigned to the current scanning section number indicated by the extraction section setting scanning unit 21 as a measure of the envelope value of the section of interest.

FIG. 3 is a flowchart of the operation of the envelope extraction circuit 2.

First, the sampling frequency F _S and the tone frequency Freq are input to calculate the number N of tone data in the extraction section (S
1, S2, S3). As a result, the data for the basic cycle of the musical tone is exactly contained in one extraction section.

Furthermore, the length (seconds) of the musical tone is input, and the total number M of extraction sections is obtained from this information, the sampling frequency and the number of data in one extraction section (S4, S5).

The variable j of the extraction section number is initialized to "1" (S6). Initialize the variable i at the data position in the section of interest to "1", and initialize the variable SUM of the sum of squares of the first to i-th data in the section of interest to "0" ( S7, S8),
When i = N, the square of the tone data value at the current position i is squared Aij ² until the scanning within the currently focused section is completed (S10).
Is added to SUM (S9), and the tone data number i in the interval is incremented by 1 for the next addition (S11). Therefore, when i reaches N, SUM becomes
This means that the sum of squares of the musical sound data in the extracted section scanned this time, that is, the waveform power is stored.

Then, when i reaches N, SUM is divided by the number of data N in the extraction section, and the result is the j-th envelope value variable Ej
(S12), the extraction section number j is incremented by 1 to proceed to the processing of the next extraction section (S14). The above process is repeated until j reaches M (S13), that is, until the extraction of envelope values in all extraction intervals is completed.

After completion of the process shown in FIG. 3, the sequence from E ₁ to E _M is
The M envelope data extracted from the musical tone data is shown.

Note that the processing of S12 in FIG. 3 is merely for actualization and has no special meaning. In short, the envelope value is equivalent to the waveform power in each extraction section.

FIGS. 4 to 7 show examples of waveforms of musical tone data and examples of waveforms of envelope data extracted according to this embodiment. FIG. 4 shows the waveform of the attenuated sound trumpet, and FIG. 5 shows the waveform of the envelope data extracted from this waveform data. FIG. 6 shows a waveform of a continuous sound trumpet, and FIG. 7 shows an envelope waveform extracted from this.

In the above embodiment, as the extraction section,
A section corresponding to the cycle of the waveform is selected as the section of the waveform data to be inspected for extracting one envelope data, but a section corresponding to another predetermined cycle (e.g., equal to twice the tone cycle). Section) may be selected as the extraction unit section.

[Effect of the Invention] As described above in detail, in the present invention, all the sections of the sampled waveform data are subdivided, and each subdivided subsection is used as an extraction unit to determine the waveform power (each The envelope is extracted by calculating the sum of squares of the data values. Therefore, the elements of the sampled musical sound are finely and accurately obtained, and the musical characteristics are not lost.

[Brief description of drawings]

1 is an overall configuration diagram of an envelope extraction device according to an embodiment of the present invention, FIG. 2 is a configuration diagram of a main part of an envelope extraction circuit, FIG. 3 is a flowchart showing the operation of the envelope extraction circuit, and FIG. FIG. 5 is a waveform diagram showing an example of a tone waveform, FIG. 5 is a waveform diagram showing an envelope waveform extracted according to the embodiment based on the tone waveform of FIG. 4, FIG. 6 is a waveform diagram showing another example of a tone waveform, FIG. 7 is a waveform chart showing an envelope waveform extracted according to the embodiment based on the waveform of FIG. 1 ... tone data memory, 2 ... envelope extracting circuit, 3 ... extracting envelope memory, 21 ... extracting section setting scanning section, 22 ... internal section tone data reading section, 23 ... sum of squares calculating section.

Claims (1)

(57) [Scope of utility model registration request] 1. An envelope extraction device for extracting envelope data from sampled waveform data, comprising segment dividing means for subdividing an entire waveform segment of the waveform data into a plurality of small segments, and waveforms included in each of the small segments. A means for calculating the sum of squares of each value of the data, and a means for determining an envelope value specific to each small section based on the magnitude of the sum of squares calculated for each small section. Characteristic envelope extraction device.