JP5001664B2 - Signal converter - Google Patents

Description

  The present invention relates to a signal conversion device used for analyzing vibration and noise.

  In the manufacturer, the noise and vibration are controlled by performing noise analysis and vibration analysis before shipping the product so that the noise and vibration when using the product do not cause discomfort to the user. We are striving to bring this to the market. When performing the noise analysis or the vibration analysis, a so-called signal conversion device may be used. When this signal conversion device is used, the noise and vibration state is analytically verified and effective measures are taken. (For example, refer to Patent Document 1).

  In such a signal conversion device, the frequency axis is divided into a large number and the frequency filter provided for each frequency region on the divided frequency axis, and the signal for each frequency band divided by each frequency filter A combining unit that combines and outputs the same number of operators as the number of frequency filters for individually adjusting the amplitude of the components, and a signal component after adjusting at least one of those operators and the other signal components; Some are equipped with.

  According to such a signal conversion device, for example, an original time waveform signal representing noise generated from an engine or vibration generated by the operation of the engine is input to the signal conversion device, and a signal representing noise input first. A signal representing vibration is decomposed into signal components for each frequency band by the frequency filter, and the amplitude of at least one signal component of the decomposed signal components is adjusted by adjusting at least one of the operators. The adjusted and further adjusted signal component and the signal component that has passed through the frequency filter without being adjusted are synthesized by the synthesis unit, and a synthesized signal representing another noise and a synthesized signal representing another vibration are output.

  When a synthesized signal representing another noise or a synthesized signal representing new vibration is output, the tester can produce a sound different from the noise emitted from the engine or vibration caused by the operation of the engine. The state of noise and vibration is confirmed by sound emitted from the speaker and display on the display screen. In this way, it is possible to verify the noise and vibration analytically while changing the state of the noise and vibration by adjusting the amplitude of the frequency band of the analysis target (that is, the frequency band that is the main component of noise and vibration). If possible, effective measures against noise and vibration can be taken.

However, for example, noise generated from the engine and vibration when the engine is operating often include a fluctuation component that periodically varies with time. The fluctuation component that periodically fluctuates in time cannot be completely separated by the frequency filter provided in the signal converter.
JP 2001-311659 A

  In view of the above circumstances, an object of the present invention is to provide a signal conversion apparatus that can freely change the amplitude and period of a fluctuation component that varies with time among signal components that constitute noise and vibration. .

The signal conversion device of the present invention that achieves the above object, based on a first time waveform signal, an envelope extraction unit that generates a first envelope waveform signal representing an envelope of the first time waveform signal;
Second amplitude obtained by converting the amplitude of the first time waveform signal into a constant amplitude in time using the first time waveform signal and the first envelope waveform signal generated by the envelope extraction unit. And a first time waveform calculation unit for generating the time waveform signal.

  According to the signal conversion apparatus of the present invention, the envelope extraction unit extracts a first envelope waveform signal representing an envelope of the first time waveform signal based on the first time waveform signal. The first envelope waveform signal corresponds to a time waveform signal of a fluctuation component in noise or vibration. The first time waveform calculation unit generates the second time waveform signal other than the time waveform of the fluctuation component.

  That is, according to the signal conversion apparatus of the present invention, the first time waveform signal is constant in time by the first time waveform calculation unit and the envelope extraction. Are separated into a second time waveform signal converted into the amplitude of the first time waveform signal and a first envelope signal representing a fluctuation component of the first time waveform signal.

  For example, if the configuration is such that the amplitude and period of the first envelope waveform signal extracted by the envelope extraction unit can be changed by an operator or the like, the amplitude and period of the time-varying fluctuation component can be freely changed. A signal conversion device capable of performing

  Here, the envelope extraction unit preferably generates the envelope waveform signal by Hilbert transform.

  When the frequency filter is composed of a digital filter composed of a processor, all can be constructed in the processor by using the Hilbert transform for the envelope extraction unit.

  In addition, the first time waveform calculation unit generates the second time waveform signal by dividing the first time waveform signal by the envelope waveform signal generated by the envelope extraction unit. Is preferred.

  As described above, when the signal conversion device is configured by a processor, in addition to the digital filter, four arithmetic operation circuits such as division can be freely configured in the processor. When the first time waveform signal is divided by the envelope waveform signal using the division circuit, the time fluctuation component is removed, and the signal excluding the time fluctuation component from among many signal components constituting noise and vibration. Ingredients are obtained.

  Here, the second time waveform signal generated by the first time waveform calculation unit and the second envelope waveform signal including a desired time fluctuation component are used to add the time to the second time waveform signal. It is preferable to further include a second time waveform calculation unit that generates a third time waveform signal to which an amplitude that varies with time according to the fluctuation component is given.

In generating the third time waveform signal in the second time waveform calculation unit,
The second time waveform calculation unit generates the third time waveform signal by multiplying the second time waveform signal generated by the first time waveform calculation unit by the second envelope waveform signal. Then,
In generating the second envelope signal,
It is preferable to provide an envelope adjustment unit that generates a second envelope waveform signal by extracting a desired time fluctuation component from the first envelope waveform signal generated by the envelope extraction unit.

  Then, only the desired time variation component is extracted from the first envelope waveform signal generated by the envelope extraction unit by the envelope adjustment unit to generate the second envelope waveform signal, and the second envelope waveform and A third time waveform obtained by multiplying the second time waveform signal by the time waveform calculation unit and changing the content of the time-varying fluctuation component of the noise and vibration input to the signal converter is obtained. Generated.

  The envelope adjustment unit generates the second envelope waveform signal by extracting a fluctuation component and a direct current component in a desired frequency band from the first envelope waveform signal generated by the envelope extraction unit. It is preferable.

  As described above, when the envelope adjustment unit is configured in the processor, the fluctuation component of the desired frequency band is calculated using the deviation from the DC component as a reference when extracting the fluctuation component of the desired frequency band. It is easy to perform processing if it is configured to extract.

In addition, a first frequency filter that generates the first time waveform signal by extracting a desired frequency band component from the original time waveform signal is provided,
A second frequency filter having a frequency characteristic equivalent to that of the first frequency filter is provided after the first time waveform calculation unit and before the second time waveform calculation unit. To do.

  Then, a predetermined process can be performed only on the frequency band component to be analyzed.

   As described above, a signal conversion device that can freely change the amplitude and period of a signal component that varies with time among signal components that constitute noise and vibration is realized.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a signal conversion apparatus 1 according to an embodiment of the present invention.

  The signal conversion device 1 in FIG. 1 is configured by a device including a CPU (processor) such as a personal computer. In this case, each of the signal conversion devices 1 is a program indicating a procedure of processing executed by the CPU included in the personal computer. The component is configured.

  In the signal conversion apparatus 1 of FIG. 1, envelope extraction for generating a first envelope waveform signal representing an envelope of the first time waveform signal based on the first time waveform signal constituted by the program. Using the unit 11, the first time waveform signal, and the first envelope waveform signal generated by the envelope extraction unit 11, the amplitude of the first time waveform signal is converted into a constant amplitude in time. And a first time waveform calculation unit 12 that generates a second time waveform signal.

  The envelope extractor 11 generates an envelope waveform signal by Hilbert transform, and the first time waveform calculator 12 divides the first time waveform signal by the envelope waveform signal generated by the envelope extractor. By doing so, the second time waveform signal is generated. In FIG. 1, reference signs A, B, C, C ′, D, and E are shown to indicate that the signals output from the respective units are different.

  Furthermore, the signal conversion apparatus 1 of the present invention uses the second time waveform signal generated by the first time waveform calculation unit 12 and the second envelope waveform signal including a desired time fluctuation component to perform the second operation. And a second time waveform calculation unit 15 for generating a third time waveform signal in which a time waveform amplitude is given to the time waveform signal according to a time variation component. The unit 15 generates a third time waveform signal by multiplying the second time waveform signal generated by the first time waveform calculation unit 12 by the second envelope waveform signal.

  The signal conversion apparatus 1 of the present invention further includes an envelope adjustment unit 13 that generates a second envelope waveform signal by extracting a desired time variation component from the first envelope waveform signal generated by the envelope extraction unit 11. The envelope adjusting unit 13 generates a second envelope waveform signal by extracting a fluctuation component and a DC component of a desired frequency band from the first envelope waveform signal generated by the envelope extracting unit 11. It is. When the envelope adjusting unit 13 is provided, the envelope adjusting unit 13 changes the amplitude and cycle of the envelope to a desired one.

  Further, the signal conversion apparatus 1 of the present invention generates a first time waveform signal by extracting a desired frequency band type component from the original time waveform signal in order to designate a frequency band to be analyzed. A frequency filter 10 is provided, and a second frequency filter 14 having a frequency characteristic equivalent to that of the first frequency filter 10 is provided after the first time waveform calculation unit 12 and before the second time waveform calculation unit 15. It has.

  The operation of the signal conversion apparatus 1 will be described with reference to FIG. 1 from the upper side corresponding to the input side to the lower side corresponding to the output side.

  First, when an original time waveform signal, for example, a time waveform signal representing engine noise, is input to the signal conversion device 1 surrounded by a dotted line, first, a first frequency filter 10 outputs signals for a number of frequency bands on the frequency axis. Are divided to obtain a first time waveform signal A composed of signal components only in the target frequency band.

  The first time waveform signal A is supplied to both the envelope extraction unit 11 and the first time waveform calculation unit 12.

  One envelope extraction unit 11 receives the first time waveform signal and performs Hilbert transform to generate a first envelope waveform signal B representing the envelope of the first time waveform signal. The first envelope waveform signal B is supplied to both the envelope adjusting unit 13 at the subsequent stage and the first time calculating unit 12.

  The other first time waveform calculation unit 12 receives both the first time waveform signal A and the first envelope waveform signal B, receives the first time waveform signal A as the dividend, and the first envelope waveform. Division is performed using the signal B as a divisor to generate a second time waveform signal C having a constant temporal amplitude. In this example, in order to increase the purity of the analysis signal, a second frequency filter 14 having a frequency characteristic equivalent to that of the first frequency filter 10 is provided after the second time waveform calculation unit 12. The second frequency filter 14 adjusts the waveform of the second time waveform signal and supplies the second time signal waveform to the second time waveform calculator 15 at the subsequent stage.

  The envelope adjustment unit 13 receives the first envelope waveform signal and extracts a desired time fluctuation component from the first envelope waveform signal to generate a second envelope waveform signal. When the second envelope waveform signal is generated from the first envelope waveform signal in this way, the frequency band of the first envelope waveform signal representing the envelope of the original time signal waveform spreads over a relatively wide band. Sometimes, only the signal component of the desired band is extracted to generate the second envelope signal, and the generated second envelope signal can be changed, so that the amplitude of the time-varying component can be changed. In addition, the period of the time variation component can be changed by changing the band to be extracted.

  In this example, for convenience of processing, the envelope adjustment unit 13 extracts a signal component and a DC component in a frequency band of a desired fluctuation component from the first envelope waveform signal B generated by the envelope extraction unit 11. A second envelope waveform signal D is generated. Thus, the second envelope waveform signal D is multiplied by the second time waveform signal C ′ whose signal purity is increased to generate a third time signal waveform E.

  Finally, all the signal components in the frequency band other than the analysis target are added by the adder 16 to output a time waveform signal in which the content of the fluctuation component is changed.

  Here, the user causes the first frequency filter included in the signal conversion device 1 of the present invention to extract the signal component of the frequency band to be analyzed from the original time signal waveform, or the envelope adjustment unit causes the signal component of the desired frequency band to be extracted. For example, an input box or the like is created on the display screen of the personal computer constituting the signal conversion device 1 so that each frequency band can be input, and the user can be extracted. It is good to make it the structure which inputs a numerical value from the input box. Further, when the third time waveform signal E is output, if the result is displayed on the display screen of the personal computer, the analysis result is displayed while changing the numerical value to be input while viewing the display screen. Since it can be confirmed on the screen, it becomes a signal conversion device that is convenient for the user.

  With reference to FIG. 2, a change in the state of the waveform after processing is executed in each unit included in the signal conversion device 1 in FIG. 1 will be described.

  FIG. 2 is a diagram illustrating a change in the state of the time signal waveform output from each unit included in the signal conversion apparatus 1 of FIG.

  2A shows the first time signal waveform A output from the first frequency filter, and FIG. 2B shows the first time signal waveform A output from the first time waveform calculation unit. 2 shows a time signal waveform C, and FIG. 2C shows a third time signal waveform E.

  The waveform shown in FIG. 2 (a) is a signal waveform output from a frequency filter having a predetermined frequency band to be analyzed as a band, and temporal variation occurs at a predetermined period.

  Conventionally, the period and amplitude of the time fluctuation of the time signal waveform could not be increased / decreased. However, in the signal conversion device 1 of FIG. 1, the fluctuation component and the other signal component are separated to It is possible to change the amplitude and period of the component.

  In this example, the envelope adjustment unit 13 in FIG. 1 increases the amplitude of the envelope waveform and multiplies it with the second time signal waveform C ′ to obtain the signal waveform in FIG.

  Since the second time signal waveform C ′ becomes a time signal waveform of the signal from which the time variation component of the signal components constituting the original signal is excluded, the amplitude increases to the second time signal waveform C ′. Is multiplied by the second envelope waveform signal, the signal obtained by changing only the time-varying component of the original time waveform signal input to the signal converter is obtained.

  Although FIG. 1 shows an example in which the amplitude is increased, it is naturally possible to decrease the amplitude.

  In the description of FIG. 1, the configuration for adjusting the amplitude and period of the fluctuation component extracted by the envelope extraction unit 11 has been described. However, the amplitude of the first time waveform signal A is changed by the first time waveform calculation unit 12. Since the second time waveform signal C converted to a constant amplitude in time is generated, the envelope extraction unit 11 and the envelope adjustment unit 13 are omitted, and the second envelope signal D is generated by them. Instead, as shown by the dotted line in FIG. 1, the function generator FG is connected to the outside, and the second envelope waveform signal D ′ arbitrarily generated by the function generator FG is arbitrarily used by the second time waveform calculation unit 15. The third time waveform signal E having the fluctuation component may be generated. Then, since the third time signal waveform E having various fluctuation components can be generated by generating various second envelope signals D ′ by the function generator FG, analysis of noise and vibration is more effective. Can be done.

  As described above, a signal conversion device that can freely change the amplitude and period of a signal component that varies with time among signal components constituting noise and vibration is realized.

It is a figure which shows the structure of the signal converter 1 which is one Embodiment of this invention. It is a figure explaining the change of the state of the time signal waveform output from each part with which the signal converter of FIG. 1 is provided.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Signal converter 10 1st frequency filter 11 Envelope extraction part 12 1st time waveform calculation part 13 Envelope adjustment part 14 2nd frequency filter 15 2nd time waveform calculation part 16 Addition part A 1st time waveform signal B first envelope waveform signal C C ′ second time waveform signal D second envelope waveform signal E third time signal waveform

Claims (5)

An envelope extractor for generating a first envelope waveform signal representing an envelope of the first time waveform signal based on the first time waveform signal;
Second amplitude obtained by converting the amplitude of the first time waveform signal into a constant amplitude in time using the first time waveform signal and the first envelope waveform signal generated by the envelope extraction unit. a first time waveform computation unit for generating time waveform signal,
Using the second time waveform signal generated by the first time waveform calculator and a second envelope waveform signal including a desired time variation component, the time variation component is added to the second time waveform signal. And a second time waveform calculation unit that generates a third time waveform signal to which a time-varying amplitude is given . The second time waveform calculation unit generates the third time waveform signal by multiplying the second time waveform signal generated by the first time waveform calculation unit by the second envelope waveform signal. The signal converter according to claim 1, wherein   The envelope adjusting unit for generating a second envelope waveform signal by extracting a desired time variation component from the first envelope waveform signal generated by the envelope extraction unit. Signal converter.   The envelope adjustment unit generates the second envelope waveform signal by extracting a fluctuation component and a DC component of a desired frequency band from the first envelope waveform signal generated by the envelope extraction unit. The signal converter according to claim 3.   A first frequency filter that generates the first time waveform signal by extracting a desired frequency band component from the original time waveform signal;
  A second frequency filter having a frequency characteristic equivalent to that of the first frequency filter is provided after the first time waveform calculation unit and before the second time waveform calculation unit. The signal converter according to claim 1.

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