Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D21/00—Measuring or testing not otherwise provided for
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
  • H04B1/02—Transmitters
  • H04B1/04—Circuits
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
  • H03B11/00—Generation of oscillations using a shock-excited tuned circuit
  • H03B11/02—Generation of oscillations using a shock-excited tuned circuit excited by spark

Definitions

• the present invention relates to a communication apparatus, and more particularly, to a data coding apparatus comprised in a data transmission apparatus.
• the present invention provides a data coding apparatus and method which can be used semi-permanently without concern about power supply.
• a data coding apparatus including: a signal input unit receiving and converts electrical signals to be encoded into surface acoustic waves; a surface acoustic wave encoder encoding the surface acoustic wave according to the input encoded signals; and a signal output unit converting and outputting the encoded surface acoustic waves as electrical signals.
• the signal input unit may include a plurality of surface acoustic converters which are sequentially arrayed in the propagation direction of the surface acoustic waves, and the surface acoustic wave encoder may further include a selection unit selecting whether or not to output a surface acoustic wave of each of the surface acoustic wave converts. Therefore, the input electrical signals can be easily encoded by using the surface acoustic waves.
• the signal input unit may convert a plurality of electrical signal inputs having the same frequency band but different phases into surface acoustic waves.
• the signal input unit may convert a plurality of electrical signal inputs having the same phase but different frequency bands into surface acoustic waves.
• the data transmission apparatus may further include a matching unit connecting the filter to the encoder. Therefore, signal transmission between the filter and the encoder can be more effectively performed.
• a data coding method used in the data coding apparatus [13] Accordingly, (1) in order to generate an output modulated signal for an input sine waveform, the SAW transmitter is properly controlled and connected to a switching network to perform modulations used for communications such as amplification modulation (AM), frequency modulation (FM), phase modulation (PM), direct sequence spread spectrum (DSSS), frequency hopping (FP), and the like, and (2) the modulations used for communications such as amplification modulation (AM), frequency modulation (FM), phase modulation (PM), direct sequence spread spectrum (DSSS), frequency hopping (FP), and the like, and (2) the modulations used for communications such as amplification modulation (AM), frequency modulation (FM), phase modulation (PM), direct sequence spread spectrum (DSSS), frequency hopping (FP), and the like, and (2) the modulations used for communications such as amplification modulation (AM), frequency modulation (FM
• SAW transmitter having a transverse type is employed to significantly reduce inserting losses and guarantee a farther data transmission distance.
• the data coding apparatus uses surface acoustic wave to perform wireless data transmission without additional electrical circuits. Therefore, very low manufacturing costs are needed.
• the data coding apparatus according to the present invention does not use power supply. Therefore, the data coding apparatus according to the present invention can be applied to a field to which a data transmission apparatus using power supply cannot be easily applied.
• FIG. 1 is a schematic block diagram illustrating a data transmission apparatus comprising a data coding apparatus according to an embodiment of the present invention.
• FIG. 2 is a schematic block diagram illustrating a white noise generator of FIG. 1.
• FIG. 3 is a schematic block diagram illustrating a filter of FIG. 1.
• FIG. 4 is a schematic block diagram illustrating an encoder of FIG. 1.
• FIG. 5 is a schematic block diagram illustrating a surface acoustic wave encoder of
• FIG. 4 is a view illustrating a conventional piezoelectric energy storage and conversion system.
• FIG. 7 is a detailed view illustrating a structure of the data transmission apparatus of FIG. 1.
• FIG. 8 is a graph illustrating breakdown voltage characteristics of electrode plates as a function of gap distance and pressure between the electrode plates.
• FIG. 9 is a view illustrating a semiconductor manufacturing process for manufacturing a spark generation structure.
• FIG. 10 is a schematic view illustrating a piezoelectric material generating a spark.
• FIG. 11 is a table listing properties and shapes for a cylindrical piezoelectric material.
• FIG. 12 is a graph illustrating piezoelectric energy conversion according to an acoustic impedance ratio.
• FIG. 13 is a table listing acoustic impedances according to materials.
• FIG. 14 is a view illustrating waveforms of electrical signals at points illustrated in
• FIG. 15 is a view illustrating an input waveform at a point F and an output waveform at a point G of FIG. 7.
• FIGS. 16 to 18 are views illustrating input coding array interdigtal transducers
• IDTs for performing frequency modulation, amplitude modulation, and phase modulation, respectively.
• FIG. 19 is a view illustrating a configuration of a coding network.
• FIG. 20 is a view illustrating comparison of the structure of the data transmission apparatus with a structure of a conventional data transmission apparatus.
• FIG. 21 is a view illustrating a structure formed by modifying the structure illustrated in FIG. 7 for frequency modulation.
• FIG. 22 is a view illustrating an example of the frequency modulation using different frequencies.
• FIG. 23 is a view illustrating a variable spark gap array and a structure of an external programmer.
• FIG. 24 is a view illustrating an example of a pattern of a coding array IDT that performs phase modulation and an output waveform.
• FIG. 25 is a table listing output values according to time points of an output terminal of the coding array IDT illustrated in FIG. 24. Best Mode for Carrying Out the Invention
• FIG. 1 is a schematic block diagram illustrating a data transmission apparatus comprising a data coding apparatus according to an embodiment of the present invention.
• the data transmission apparatus 1000 includes a white noise generator 100, a filter 200, an encoder 300, and a matching unit 400.
• the white noise generator 100 generates a white noise electrical signal.
• FIG. 2 is a schematic block diagram illustrating the white noise generator 100 of
• the white noise generator 100 includes a piezoelectric device
• the piezoelectric device 110 converts mechanical energy into electrical energy.
• the spark generator 120 generates a spark by using the electrical energy generated by the piezoelectric device 110. In addition, the spark generator 120 illustrated in FIG.
• the spark time controller 122 controls a time to generate the spark. As a method of controlling the time, controlling a distance between electrodes (not shown) for generating the spark may be used. [49] In order to perform the controlling of the distance between the electrodes, the spark time controller 122 selects one from a plurality of pairs of electrodes having different interelectrode distances.
• the pair of electrodes may be formed on a single substrate in a semiconductor manufacturing process, so that the spark generator 120 can be manufactured to have a smaller size and a more precise shape.
• the filter 200 filters the white noise electrical signal to generate an electrical signal having a predetermined band frequency.
• the predetermined band may be set by a manufacturer or a user in advance.
• FIG. 3 is a schematic block diagram illustrating the filter of FIG. 1.
• the filter 200 includes a plurality of filters 210 and 220 and a transformer 230.
• the plurality of the filters 210 and 220 have different bandwidths including frequencies in predetermined bands.
• the plurality of the filters 210 and 220 include filters 212 and 214 having wide bandwidths and filters 222 and 224 having narrow bandwidths, which are sequentially connected.
• the transformer 230 controls a strength of the electrical signal. As described above, by controlling the strength of the electrical signal, a circuit can be protected, and an efficiency can be increased.
• the filter 200 may generate different band frequency electrical signals. In order to filter different frequencies, in FIG. 3, the filters are arrayed in parallel. As described above, by generating the electrical signals having different frequencies, the encoder
• the encoder 300 encodes the frequency-filtered electrical signals.
• FIG. 4 is a schematic block diagram illustrating the encoder 300 of FIG. 1.
• the encoder 300 includes a signal input unit 310, a surface acoustic wave encoder 320, and a signal output unit 330.
• the signal input unit 310 receives and converts an to-be-encoded electrical signal into a surface acoustic wave.
• the signal input unit 310 may convert a plurality of input electrical s ignals having the same frequency band but different phases into surface acoustic waves. Therefore, phase encoding can be performed on the input electrical signals.
• the signal input unit 310 may convert a plurality of input electrical signals having the same phase but different frequency bands into surface acoustic waves. Therefore, frequency modulation can be performed on the input electrical signals.
• FIG. 5 is a schematic block diagram illustrating the surface acoustic wave encoder of FIG. 4.
• the surface acoustic wave encoder 320 includes a plurality of surface acoustic wave converters 322 and a selection unit 324.
• the surface acoustic wave converters 322 are sequentially arrayed in the propagation direction of surface acoustic waves.
• the surface acoustic wave encoder may include the selection unit 324 for selecting whether or not to output a surface acoustic wave from each of the surface acoustic wave converters.
• the signal output unit 330 converts the encoded surface acoustic wave into an electrical signal
• the matching unit 400 connects the filter 200 to the encoder
• the energy conversion system mainly includes a piezoelectric material, a piezoelectric hammer, a transformer, a rectifier circuit, a storage circuit, a constant voltage supply circuit, and the like.
• the energy conversion system has a very low energy conversion efficiency, and high loss of energy in a storing or rectifying operation, so that a practical application of the energy conversion system is limited.
• the piezoelectric energy conversion apparatus obtaining energy from surroundings which has been widely developed for self-powered/wireless data transmission. Therefore, if a problem in practical application is solved (for example, a development of a method of transmitting data by using only an impact), the piezoelectric energy conversion apparatus can be applied to a miniaturized communication system and can be widely used.
• FIG. 6 is a view illustrating a conventional piezoelectric energy storage and conversion system.
• the generated voltage has a sine waveform (generally referred to as Asin(wt)-e " ⁇ t ) that has a very high frequency and the frequency is exponentially decreased. Therefore, in order to store the voltage waveform, the voltage is rectified by using a bridge circuit 3, and the rectified voltage is stored in an energy storage device such as a capacitor 4.
• the voltage passes through a constant voltage circuit and is supplied as a constant voltage of +5 V or +3.3 V.
• a constant voltage circuit In the piezoelectric energy conversion and storage circuit illustrated in FIG. 6, enough electrical energy is stored in the capacitor only when an amount or a frequency of externally applied energy is high. This is because there is a problem of a piezoelectric conversion efficiency and very high losses with storage and regulation circuits.
• the system illustrated in FIG. 6 is useful for only a situation in which vibrations occur ordinarily and not effective for other situations. Therefore, the development of a self -powered/wireless transmission mechanism that can be operated even in a situation in which external physical energy is applied only once is needed.
• FIG. 7 is a detailed view illustrating a structure of the data transmission apparatus of FIG. 1.
• the piezo igniter when external force is applied to a piezo igniter, the piezo igniter generates a high voltage ranging from 1OkV to 2OkV.
• This operation principle is similar to that of a spark igniter of an electric lighter.
• the generated high voltage passes through a spark generator illustrated in FIG.
• the air discharge is a phenomenon that occurs when a breakdown is generated between the two electrodes connected to the piezo igniter.
• a breakdown voltage is determined by atmosphere pressure and the gap between the two electrodes.
• Paschen theoretically verifies that as a voltage between two electrodes increases, an intensity of an electric field is not continuously increased but a breakdown occurs at a predetermined voltage or more. This is called a discharge phenomenon (referred to as Paschen's Law). Paschen proposes a Paschen's curve that is a curve about a relationship between breakdown, pressure, and gap.
• FIG. 8 is a graph illustrating breakdown voltage characteristics of electrode plates as a function of gap distance and pressure between the electrode plates.
• FIG. 8 illustrates the breakdown voltage characteristics of electrode plates as a scalar product (pxd) of gap distance and pressure between the electrode plates.
• the breakdown voltage has a minimum point when a predetermined gap interval is provided between the electrode plates. With respect to the point, the breakdown voltage is increased to the right. This is because as the gap distance between the electrode plates increases, a larger amount of electric energy for generating the breakdown is needed.
• Piezoelectric ignition occurs when a piezoelectric conversion voltage that occurs due to externally applied pressure according to Paschen's Law is higher than a breakdown voltage.
• a piezoelectric material is considered to be an open circuit. However, during the ignition (or discharge), the piezoelectric material is not the open circuit but may be referred to as a system including an equivalent resistance corresponding to a discharge spark gap.
• a signal input time t is a very important variable.
• a release time t determines an on time period of an RF input r signal input to a surface acoustic wave (SAW) transmitter.
• SAW surface acoustic wave
• the release time has a different value according to a capacitance of the piezoelectric material, an equivalent resistance of the spark generation structure gap, and resistances of an electrode and a wire connected to the piezoelectric material.
• a spark gap to form an optimal release time in the semiconductor manufacturing process is formed.
• FIG. 9 is a view illustrating a semiconductor manufacturing process for manufacturing the spark generation structure.
• FIG. 10 is a schematic view illustrating the piezoelectric material generating a spark.
• a propagation velocity of an acoustic shock wave is different according to a medium.
• a propagation velocity of a conventional piezoelectric material is about 4mm/ms.
• the release time of the electrical energy due to the piezoelectric ignition is ID or less.
• energy generated by piezoelectric effect from a time point at which the acoustic shock wave is generated is in a state converted into a different form before the acoustic shock wave is propagated to the opposite side.
• a time interval between the propagation velocity of the mechanical acoustic wave energy and the release time of piezoelectric energy enables multiple energy generation.
• the multiple energy generation is a phenomenon in which although external stress is not added, while the acoustic shock wave is propagated, the propagation of the acoustic wave practically shows such an effect that stress is continuously exerted to the piezoelectric material for the propagated time of the acoustic wave.
• Additional electrical energy generated during the propagation time of the acoustic shock wave is represented by U and defined as follows.
• Equation 3 decrease in energy conversion efficiency corresponding to a piezoelectric coupling coefficient does not occur. It means that theoretically externally applied mechanical energy is converted into electrical energy.
• Equation 3 is represented by using an energy density as follows.
• Equation 6 is obtained as follows.
• Equation 6 practically, if there is no big difference between A H and A C , it is assumed that A A . In this case, Equation 6 is changed as follows. [130] [Equation 7]
• Equation 7 As a relationship between Z and Z that are acoustic impedances,
• Equation 7 Equation 7A
• Piezoelectric energy conversion in consideration of impacts may be represented as a graph in FIG. 12 by substituting data in FIG. 11 for Equation 7.
• An amount of piezoelectric energy conversion may have a value ranging from 30x10 v to 100x10 v [J] according to an acoustic impedance ratio Z Z .
• FIG. 11 is a table listing properties and shapes for the cylindrical piezoelectric material.
• FIG. 12 is a graph illustrating piezoelectric energy conversion according to the acoustic impedance ratio.
• an acoustic impedance ratio between the piezoelectric material and the impact hammer has to be high (Z Z ⁇ 0.5).
• the acoustic impedance ratio cannot have a high value.
• FIG. 13 is a table listing acoustic impedances according to materials.
• a high voltage generated by exerting an instant impact to the piezoelectric material generates a spark as described above, and like a spark in a normal life, the generated spark is similar to white noise that affects most of electronic products. Specifically, the spark has signal strength in most of a frequency spectrum as illustrated in FIG. 14a.
• FIG. 14 is a view illustrating waveforms of electrical signals at points illustrated in
• a filter having a proper pass bandwidth in a proper frequency band that is, a first band pass filter (BPF) illustrated in FIG. 7
• BPF first band pass filter
• the first band pass filter has a band that is wide enough. Specifically, when a narrow-band filter is first used in order to fix a form of a signal that is initially generated like white noise, there are problems of decrease in the total efficiency and additional signal deterioration. In addition, since the signal strength of the white noise is too high due to the spark that is primarily generated, dielectric breakdown of the narrow-band filter may occur.
• a practical strength of a frequency-filtered signal may cause dielectric breakdown of the narrow-band filter and other devices. Therefore, a transformer is mounted after the first filter as illustrated in FIG. 7.
• the transformer may allow a secondary voltage to have a high or a low value according to a turns ratio between the numbers of turns of primary and secondary coils. Therefore, by using the aforementioned characteristics, a signal voltage to be passed through a point 'C illustrated in FIG. 7 is controlled to have a proper value.
• FIG. 14b illustrates a signal after passing through the point 'C and
• FIG. 14c illustrates a secondary voltage after passing through the transformer.
• a frequency-filtered band of the voltage controlled to have a proper value by the transformer is similar to that of the voltage before passing through the transformer as illustrated in FIG. 14c. However, a signal strength thereof is controlled by the turns ratio of the transformer.
• the signal passing through the secondary coil of the transformer is in a frequency- filtered state by the first band-pass filter (to the wide-band).
• the signal In order for the signal to be input to the SAW transmitter, the signal has to be filtered to have a narrower band.
• FIG. 14e When passing the signal through a second narrow-band-pass filter, a narrow band spectrum can be obtained as illustrated in FIG. 14e.
• FIG. 14e When FIG. 14e is represented in the time domain, a clean sine waveform can be obtained as illustrated in FIG. 15a, and the signal is the signal input to the SAW transmitter.
• FIG. 15 is a view illustrating an input waveform at a point F and an output waveform at a point G.
• a sine waveform input to the SAW transmitter is an input signal input to a coding array interdigtal transducer (IDT) illustrated in FIG. 7.
• IDT coding array interdigtal transducer
• AM amplitude modulation
• FM frequency modulation
• PM phase modulation
• spread spectrum modulation and the like may be performed on an output signal.
• a reflective delay line type used for a SAW self-powered/wireless sensor is used.
• a transverse type is used.
• FIGS. 16 to 18 are views illustrating input coding array IDTs for performing frequency modulation, amplitude modulation, and phase modulation, respectively.
• the input coding array IDTs illustrated in FIGS. 16 to 18 are examples to show that various types of modulation can be performed according to the present invention. Besides, direct sequence spread spectrum (DSSS), frequency hopping, and the like can be used.
• DSSS direct sequence spread spectrum
• frequency hopping frequency hopping
• the transverse type capable of minimizing losses is applied to the SAW transmitter.
• most of coding methods using SAW devices is a fixed coding method.
• a coding network as illustrated in FIG. 19 is used to apply a variable coding method.
• FIG. 19 is a view illustrating a configuration of the coding network.
• FIG. 18 illustrates phase modulation.
• BPSK binary -phase shift keying
• the "fl IDT" of FIG. 16 corresponds to an "in-phase IDT” of FIG. 18, and the “f2 IDT” of FIG. 16 corresponds to a " 180° out-of phase IDT of FIG. 18.
• an in-phase or out- of phase signal is output to the output IDT, so that a phase-modulated signal can be output.
• FIG. 21 According to the present invention, when the structure for the frequency modulation as illustrated in FIG. 16 is applied, an array of some devices illustrated in FIGS. 7 and 20 is changed. This is represented in FIG. 21.
• FIG. 20 is a view illustrating comparison of the structure of the data transmission apparatus illustrated in FIG. 1 with a structure of a conventional data transmission apparatus.
• FIG. 21 is a view illustrating a structure formed by modifying the structure illustrated in FIG. 7 for frequency modulation.
• FIG. 20 The structure illustrated in FIG. 20 is similar to the structure illustrated in FIG. 7, and operations illustrated in FIG. 21 are similar to those illustrated in FIG. 22.
• frequency modulation can be performed by using the SAW.
• FIG. 22 is a view illustrating an example of the frequency modulation using different frequencies.
• proper time gating has to be performed to select a proper on time period of a SAW transmitter input signal that is a signal at a point F or F' illustrated in FIG. 14a or 22.
• IDT bits of the input coding array occurs, so that a solution for the signal overlap has to be provided in advance.
• an on time period of an RF input signal is related to a release time of a spark gap. Therefore, when the spark gap is manufactured through the manu- facturing process as illustrated in FIG. 9 so as to enable a variable release time as illustrated in FIG. 23 so that the methods such as AM, FM, PM, DSSS, frequency hopping, and the like can be applied.
• the on time period input to the SAW transmitter is variable, a spark gap dedicated for every situation is not needed, and this is an object to be implemented according to the present invention.
• FIG. 23 is a view illustrating a variable spark gap array and a structure of an external programmer.
• the semiconductor manufacturing process illustrated in FIG. 9 is performed by using a micromachining (MEMS) technology applied to manufacture the spark gap structure to enable the variable on time as illustrated in FIG. 23.
• MEMS micromachining
• manufacturing process control can be performed to the sub-micron level. Referring to the Paschen's Curve as illustrated in FIG. 8, the spark gap has to be manufactured to have precision at the level of micrometer D. Therefore, a micromachining process that overcomes the limitations of the general machining process may be applied.
• FIG. 24 is a view illustrating an example of a pattern and an output waveform of a coding array IDT that performs phase modulation.
• FIG. 25 is a table listing output values according to time points of an output terminal of the coding array IDT illustrated in FIG. 24.
• the present invention relates to a method and apparatus which can operate without a power source by using the piezoelectric material and the SAW device and can wirelessly transmit data to a receiver.
• the apparatus includes the piezoelectric material, a discharger designed to generate a spark when receives an impact, a frequency filter filtering white noise generated from the spark to remain only a predetermined frequency band, and a SAW passive modulator/transmitter that receives a continuous wave signal output from the frequency filter to perform data encoding and modulation on the continuous wave signal and transmits the modulated data as airwaves.
• the energy conversion apparatus using a conventional piezoelectric material is modified to overcome disadvantages of decrease in conversion efficiency caused by using piezoelectric material and an additional conversion circuit and increase in losses and can operate using a small amount of mechanical energy (impact, pressure, and vibration).
• a conventional piezoelectric energy conversion system includes an electric circuit and needs high costs.
• piezoelectric energy conversion is used, and the converted energy is used to perform wireless data transmission.
• basic electrical circuits are not used, so that very low manufacturing costs are needed.

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Citations (6)

• 2007
  • 2007-02-15 KR KR1020070015892A patent/KR100888248B1/ko not_active IP Right Cessation
• 2008
  • 2008-02-15 WO PCT/KR2008/000910 patent/WO2008100110A1/en active Application Filing

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