Patent Publication Number: US-2005116742-A1

Title: Non-fixed oscillatory wave signal generating method and apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application claims priority of Taiwanese Application No 092133387, filed on Nov. 27, 2003.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to the generation of oscillatory wave signals, more particularly to a method and apparatus for generating a non-fixed oscillatory wave signal that is suitable for electrotherapeutic applications.  
      2. Description of the Related Art  
      In conventional electrotherapy, a specific oscillatory wave signal is applied to a human body for physical therapy. However, since the human body is able to adapt to the stimulus of the specific oscillatory wave signal after a period of exposure to the same, the desired therapeutic effect cannot be ensured.  
     SUMMARY OF THE INVENTION  
      Therefore, the object of the present invention is to provide a method and apparatus for generating a non-fixed oscillatory wave signal that is suitable for application to a patient undergoing electrotherapy.  
      According to one aspect of the present invention, there is provided a method of generating an oscillatory wave signal. The method comprises the steps of: 
          a) establishing a set of digitized time-domain basic wave signals;     b) transforming the digitized time-domain basic wave signals into a corresponding set of frequency spectra;     c) randomly processing the set of frequency spectra;     d) combining the set of frequency spectra processed in step c) so as to obtain a mixed spectrum;     e) transforming the mixed spectrum into a time-domain synthesized wave signal corresponding to the mixed spectrum; and     f) converting the synthesized wave signal into an analog wave signal.        

      According to another aspect of the present invention, there is provided an apparatus for generating an oscillatory wave signal. The apparatus comprises: 
          a signal generating module for establishing a set of digitized time-domain basic wave signals;     a first transforming unit coupled to the signal generating module for transforming the digitized time-domain basic wave signals into a corresponding set of frequency spectra;     a processing unit coupled to the first transforming module for randomly processing the set of frequency spectra;     a combining module coupled to the processing unit for combining the set of frequency spectra processed by the processing unit so as to obtain a mixed spectrum;     a second transforming unit coupled to the combining module for transforming the mixed spectrum into a time-domain synthesized wave signal corresponding to the mixed spectrum; and     an output module coupled to the second transforming unit for converting the synthesized wave signal into an analog wave signal and for outputting the analog wave signal.       

    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which:  
       FIG. 1  is a schematic block diagram illustrating an apparatus for implementing the preferred embodiment of a method of generating an oscillatory wave signal according to the present invention;  
       FIG. 2  is a flow chart illustrating how the apparatus of  FIG. 1  generates an oscillatory wave signal in accordance with the method of the preferred embodiment;  
       FIGS. 3   a  to  3   c  are plots of exemplary digitized time-domain basic wave signals (XG, XH, XM) established in the preferred embodiment;  
       FIG. 4   a  to  4   c  are plots of frequency spectra transformed from the digitized time-domain basic wave signals (XG, XH, XM) of  FIGS. 3   a  to  3   c;    
       FIG. 5  is a chart to illustrate how the frequency spectra of  FIGS. 4   a  to  4   c  are combined in accordance with the preferred embodiment; and  
       FIG. 6  is a plot of a time-domain synthesized wave signal resulting from the processing of the digitized time-domain basic wave signals (XG, XH, XM) in accordance with the preferred embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       FIG. 1  illustrates an apparatus configuration for implementing the preferred embodiment of a method of generating a non-fixed oscillatory wave signal according to the present invention. The apparatus includes a signal generating module  11 , a first transforming unit  12 , a processing unit  13 , a combining module  14 , a second transforming unit  15 , an amplitude adjusting unit  16 , and an output module  17 .  
      The signal generating module  11  is operable so as to establish a set of digitized time-domain basic wave signals in a trial-and-error manner. In this embodiment, the set of digitized time-domain basic wave signals, which can be stored in a database  110  built-in the signal generating modules  11 , includes three digitized time-domain basic wave signals (XG, XH, XM) that are suitable for application to a patient undergoing electrotherapy, as shown in  FIGS. 3   a  to  3   c.    
      The first transforming unit  12  is coupled to the signal generating module  11 , and is operable so as to transform the digitized time-domain basic wave signals (XG, XH, XM) into corresponding frequency spectra, as shown in  FIGS. 4   a  to  4   c . In this embodiment, the first transforming unit  12  performs Fast Fourier Transform to obtain the frequency spectra. Each of the frequency spectra includes a baseband spectral component and a plurality of harmonic spectral components. The frequencies of the harmonic spectral components are determined according to the following Equation 1: 
 
 f   n   =f   o   +f   i   ×n   (Equation 1) 
 
 where f o  denotes the frequency of the baseband spectral component, f n  denotes the frequency of the n th  harmonic spectral component, and f i  denotes the frequency difference between the baseband spectral component and the first harmonic spectral component or between adjacent ones of the harmonic spectral components, where “n” is a natural number, and where f n , f o  and f i  are positive real numbers. 
 
      The processing unit  13  is coupled to the first transforming module  12 , and is operable so as to randomly process the set of frequency spectra. In this embodiment, the processing unit  13  randomly processes the frequency spectra by multiplying a frequency scale of each of the frequency spectra by a random natural number chosen independently of those used to process other ones of the frequency spectra. In this example, the random natural number for each of the frequency spectra is equal to 1.  
      The combining module  14  is coupled to the processing unit  13  and is operable so as to combine the frequency spectra processed by the processing unit  13 , thereby resulting in a mixed spectrum, as shown in  FIG. 5 .  
      The second transforming unit  15  is coupled to the combining module  14 , and is operable so as to transform the mixed spectrum into a time-domain synthesized wave signal. In this embodiment, the second transforming unit  15  performs Inverse Fast Fourier Transform to obtain the synthesized wave signal.  
      The amplitude adjusting unit  16  is coupled to the second transforming unit  15 , and is operable so as to adjust amplitudes of the synthesized wave signal such that the latter is suitable for application to a human body, as shown in  FIG. 6 . In this embodiment, the amplitude adjusting unit  16  divides each of the amplitudes of the synthesized wave signal by an average of the amplitudes of the synthesized wave signal  
      The output module  17  is coupled to the amplitude adjusting unit  16 , and is operable so as to convert the synthesized wave signal adjusted by the amplitude adjusting unit  16  into an analog wave signal and so as to output the analog wave signal in the form of small current and low voltage via an electrode (not shown) In this embodiment, the analog wave signal outputted by the output module  17  is the non-fixed oscillatory wave signal, and is suitable for application to a patient undergoing electrotherapy.  
      Referring to  FIG. 2 , there is shown a flow chart to illustrate how the apparatus generates the non-fixed oscillatory wave signal in accordance with the method of the preferred embodiment. In step S 1 , the signal generating module  11  is operable so as to establishe the set of digitized time-domain basic wave signals (XG, XH, XM). In step S 2 , the first transforming unit  12  transforms the digitized time-domain basic wave signals (XG, XH, XM) into the corresponding set of frequency spectra. In step S 3 , the processing unit  13  randomly processes the set of frequency spectra. In step S 4 , the combining unit  14  combines the set of frequency spectra processed by the processing unit  13  so as to obtain the mixed spectrum. In step S 5 , the second transforming unit  15  transforms the mixed spectrum into a time-domain synthesized wave signal corresponding to the mixed spectrum. In step S 6 , the amplitude adjusting unit  16  adjusts the amplitudes of the synthesized wave signal so as to be suitable for application to a human body. In step S 7 , the output module  17  converts the synthesized wave signal adjusted by the amplitude adjusting unit  16  into the analog wave signal (i.e., the non-fixed oscillatory wave signal that is suitable for a patient undergoing electrotherapy).  
      To sum up, this invention discloses the generation of non-fixed oscillatory wave signals for application to a patient undergoing electrotherapy. Because of the non-fixed characteristics of the oscillatory wave signal, the human body is unable to adapt to its stimulus after a period of exposure to the same, thereby ensuring the desired therapeutic effect.  
      While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.