JP2005217709A - Saw matched filter and transmitter and receiver employing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a SAW matched filter satisfying improvement of noise immunity of a signal, low power consumption of an apparatus, a low cost and downsizing in communication adopting a super-broadband wireless communication system, and also to provide a transmitter and a receiver employing the SAW matched filter. <P>SOLUTION: The SAW matched filter 3 for outputting signals subjected to spread spectrum processing by a code sequence PNO and multi-banded into four wave band signals generates a reference signal used for a criterion of data. On the other hand, on the basis of transmission data, a SAW matched filter 7 or 8 for outputting signals is subjected to spread spectrum processing by a code sequence PN1 the speed and the length of which are the same as those of the code sequence PN0 and the code arrangement of which differs from that of the code sequence PN0. The SAW matched filter 7 or 8 generates signals multi-banded into four waves of band signals, and also generates a data signal whose time differs from a reference signal generated by the SAW matched filter 3 by a time τ and transmits the data signal together with the reference signal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a SAW matched filter used for communication using a spread spectrum signal, and a transmitter and a receiver using the SAW matched filter.

  In recent years, as a new data communication method for spread spectrum communication, there is an ultra-wideband wireless communication method in which data is spread over an extremely wide frequency band of about 1 [GHz] and data is transmitted and received by superimposing data on pulses without using a carrier wave. Attention has been paid. In this method, since data transmitted in each frequency band has only a noise level, there is an advantage that there is no interference with a wireless device using the same frequency band and power consumption is low.

  In this method, a repetitive code that transmits a predetermined number of impulses for each bit is generally used. Specifically, using binary pulse position modulation (BPPM), for example, a pulse corresponding to bit “1” is transmitted δ seconds later than a pulse corresponding to bit “0”. . Further, the pulse signal in each frame is transmitted after being subjected to spectrum spreading in which the pulse position is changed by time hopping based on a user-specific spreading code (see, for example, Non-Patent Document 1).

  In addition to the method of performing spread spectrum by time hopping as described above, the ultra-wideband wireless communication method includes a method of directly spreading the code of the pulse in each frame using a user-specific spread code. In order to perform transmission / reception by performing spread spectrum, a transmitter and a receiver require a correlator or matched filter that performs spreading or despreading. Furthermore, the ultra-wideband wireless communication system does not use the wideband as it is, but multibands using, for example, OFDM (Orthogonal Frequency Division Multiplexing), etc., and includes a high-speed frequency switching PLL, etc. There has also been proposed a method in which a plurality of users simultaneously transmit data while hopping (see, for example, Non-Patent Document 2).

On the other hand, as a correlator and a matched filter used when transmitting / receiving a spectrum spread signal, for example, there is a SAW matched filter using a SAW element using a surface acoustic wave (SAW). Since the SAW matched filter is a passive component that does not require power, the transmitter or the receiver can save power (for example, see Patent Document 1).
JP 09-31548 A Naotake Yamamoto, Tomoaki Ohtsuki, Internal Turbo-Coded Ultra Wideband-Impulse Radio (ITU-UWB-IR) system characteristic evaluation, IEICE, IEICE Technical Report, Technical Report of IEICE. pp. 25-30 RCS2002-55 (2002-05) Araki Junmichi, Circuit Technology for UWB, IEICE, MWE2003 Microwave Workshop, pp 539-546

  By the way, although the ultra-wideband wireless communication system has an advantage that a large-capacity communication path can be used compared to other narrow-band communications, the transmission output is suppressed to a low level according to the standard. There is a problem that it can be used only for communication at a very short distance. If the transmission power can be increased to the maximum within the standard, the communication transmission distance that can use a large-capacity communication path can be extended. Specifically, it is sufficient that the transmission power can be increased within the standard with respect to the spectrum of the transmission / reception wave of the conventional ultra-wideband wireless communication system shown in FIG. In FIG. 16, the bold line represents the frequency range and power density of the ultra-wideband wireless communication system determined by the standard.

  However, as a method of increasing the transmission power of the spectrum signal shown in FIG. 16, a method of widening the frequency bandwidth of the signal is conceivable. However, when the frequency bandwidth of the signal is simply widened, Since there is no change in the maximum amplitude of the pulse signal, the noise resistance of the signal cannot be increased. Further, as described above, when a SAW matched filter is used for power saving in the transmitter or receiver, in order to widen the frequency bandwidth of the signal, the pass bandwidth of the SAW matched filter is also increased. However, SAW matched filters increase the insertion loss when the passband is widened, which increases the burden on active components that require power, such as amplifying the signal after the SAW matched filter. There is a problem of increasing.

  Therefore, as shown in FIG. 15, a method of dividing the signal into frequencies f1, f2, f3, and f4 that are arranged at equal intervals within the standard has been proposed. However, in order to make it multiband, it is necessary to provide a signal processing unit corresponding to a plurality of multiband frequencies in a conventional transmitter or receiver, and the circuit configuration of the transmitter or receiver is complicated. In addition, there is a problem that the power consumption and the cost of the transmitter or receiver increase, and the size of the transmitter or receiver increases. On the other hand, as a method for converting a signal into multibands, there is also a method using OFDM as described above. However, OFDM is modulated by inverse fast Fourier transform (IFFT) in a transmitter, and fast Fourier in a receiver. Since a process requiring a lot of calculations such as demodulation by FFT (FFT: Fast Fourier Transform) is required, similarly, there is a problem that the power consumption and cost increase in the transmitter or the receiver are increased, and further, the size is increased. is there.

  The present invention has been made in view of the above problems, and in communication using an ultra-wideband wireless communication system, the transmission distance is increased by improving the noise resistance of the signal, the power consumption of the device is reduced, and the cost is reduced. It is an object of the present invention to provide a SAW matched filter that can achieve both miniaturization and a transmitter and receiver using the SAW matched filter.

  In order to solve the above-mentioned problem, a SAW matched filter according to the invention of claim 1 is formed by an electrode formed on a piezoelectric substrate (for example, piezoelectric substrates S31, S41, S51, S61, and S71 in the embodiments described later). An input electrode portion for exciting a surface acoustic wave (for example, input electrode portions S3A, S4A, S5A, S6A, S7A in the embodiments described later) and the surface acoustic wave in one cycle time of a code constituting a desired code string A plurality of positive and negative electrode finger pairs arranged at right angles to the direction in which the surface acoustic wave propagates based on the distance propagated by and the number of codes constituting the code string, and the positive electrode fingers constituting the positive and negative electrode finger pairs And an output electrode section (for example, output electrode sections S3B, S4B, S5B, S6B, and S7B in the embodiments described later) having positive and negative bipolar bus bars to which a negative electrode finger is connected. In the matched filter, each of the positive and negative electrode finger pairs has a one-to-one correspondence with the polarity of the code in the order of the codes constituting the code string, and N (N is an integer of 2 or more) different resonance frequencies. It is characterized by resonating with either.

  In the SAW matched filter having the above configuration, the positive and negative electrode finger pairs resonate at any one of N different resonance frequencies. Therefore, when the input signal is a broadband signal, the surface acoustic wave excited from the input electrode unit is used. Is changed based on a desired code string determined by the arrangement of the positive and negative electrode finger pairs, spreads the input signal by the desired code string, and depends on N resonance frequencies at which the positive and negative electrode finger pairs resonate. The energy of the input signal can be divided into N-wave signals, and a multiband spectrum signal can be output. On the other hand, when the input signal is a multi-band spread spectrum signal, a change in the surface acoustic wave excited from the input electrode unit is detected, and according to N resonance frequencies at which the positive and negative electrode finger pairs resonate, By combining the energy of the signal divided into N waves into one and taking out the correlation output signal between the desired code sequence determined by the arrangement of the positive and negative electrode finger pairs and the input signal, it is applied to the input signal. Spread spectrum can be despread.

  The SAW matched filter according to the second aspect of the present invention is an input for exciting surface acoustic waves by an electrode formed on a piezoelectric substrate (for example, piezoelectric substrates P31, P41, P51, P61, P71 in the embodiments described later). An electrode part (for example, input electrode parts P3A, P4A, P5A, P6A, and P7A in an embodiment described later), a pair of positive and negative electrode finger pairs arranged perpendicular to the direction in which the surface acoustic wave propagates, and the positive and negative To arrange a plurality of positive and negative bus bars each having a positive electrode finger and a negative electrode finger constituting an electrode finger pair connected in parallel based on the number of codes constituting the code string, and to extract an output signal And an output electrode portion (for example, output electrode portions P3B, P4B, P5B, P6B, and P7B in embodiments described later) in which the bus bars on the positive electrode side are connected to each other. The positive and negative electrode finger pairs each correspond to the polarity of the Mth code so that the Mth code (M is an integer of 1 or more) of the desired code string has a one-to-one correspondence. In addition, the surface acoustic wave is arranged based on the distance that the surface acoustic wave propagates from the input electrode portion at a time M times the one cycle time of the code, and N (N is an integer of 2 or more) different resonance frequencies. It is characterized by resonating with any of the above.

  In the SAW matched filter having the above configuration, as in the SAW matched filter according to claim 1, when the input signal is a wideband signal, the input signal is determined by the arrangement of the positive and negative electrode finger pairs. And spread the spectrum of the input signal into N-wave signals according to N resonance frequencies at which the positive and negative electrode finger pairs resonate, and output a multiband spectrum signal. Can do. On the other hand, when the input signal is a multi-band spread spectrum signal, similarly to the SAW matched filter according to claim 1, the energy of the signal divided into N waves is combined into one and the positive and negative electrodes By extracting a correlation output signal between a desired code sequence determined by the arrangement of the finger pair and the input signal, the spread spectrum applied to the input signal can be despread.

  A SAW matched filter according to a third aspect of the present invention is the SAW matched filter according to the first or second aspect, wherein the distance between the positive and negative electrode finger pairs from the input electrode portion is a desired value between input and output signals. The delay time is determined by the distance that the surface acoustic wave propagates.

  The SAW matched filter having the above configuration functions as a delay element that delays a signal using the propagation time of a surface acoustic wave, and can give a delay of an arbitrary time to an input signal.

  A SAW matched filter according to a fourth aspect of the present invention is the SAW matched filter according to any one of the first to third aspects, wherein a resonance frequency of the positive / negative electrode finger pair is the positive electrode finger and the negative electrode finger. It is determined by the distance between.

  The SAW matched filter having the above configuration can easily change the resonance frequency of the positive / negative electrode finger pair according to the distance between the positive electrode finger and the negative electrode finger constituting the positive / negative electrode finger pair for each positive / negative electrode finger pair. can do.

  A SAW matched filter according to a fifth aspect of the present invention is the SAW matched filter according to any one of the first to fourth aspects, wherein the resonance frequency is continuous at a predetermined frequency interval.

  The SAW matched filter having the above configuration disperses the energy of the input signal into a continuous signal at a predetermined frequency interval based on a resonance frequency continuous at a predetermined frequency interval, thereby reducing a given frequency bandwidth. It can be used as effectively as possible.

  A transmitter according to a sixth aspect of the present invention is a transmitter for transmitting a spread spectrum signal, and includes the SAW matched filter according to any one of the first to fifth aspects.

  A transmitter having the above configuration transmits N spread spectrum signals using the SAW matched filter according to any one of claims 1 to 5, so that N resonance frequencies at which the SAW matched filter resonates are transmitted. Accordingly, it is possible to easily transmit a spectrum signal that is multibanded into an N-wave signal.

  According to a seventh aspect of the present invention, there is provided a transmitter that generates a periodic pulse (for example, a pulse generator 1 of an embodiment to be described later) and, when the periodic pulse is input, spreads spectrum using a first code string. The first spread modulation means (for example, a SAW matched filter 3 in an embodiment to be described later) that outputs a reference signal serving as a data determination reference, and when the periodic pulse is input, the first code string Is spread spectrum by a second code string having the same speed and length and different code arrangement, and second spread modulation means for outputting a data signal whose time is different from the reference signal by a first predetermined time ( For example, when a SAW matched filter 7) of an embodiment described later and the periodic pulse are input, the spectrum is spread by the second code string, and the reference signal and the second predetermined signal are A third spread modulation means (for example, a SAW matched filter 8 in an embodiment to be described later) that outputs data signals having different times, and when the transmission data is a first level of a binary logic level, When the transmission data is input to the second spread modulation means and the transmission data is at the second level of the binary logic level, the data control section (for example, in the embodiment described later) for inputting the periodic pulse to the third spread modulation means. When the switch 4 and the control circuit 6) and the transmission data are at the first level of the binary logic level, the output of the second spread modulation means is selected and the output signal of the first spread modulation means When the transmission data is a second level of a binary logic level, a selection / combining unit (selecting and combining the output of the third spread modulation means and combining with the output signal of the first spread modulation means) For example The transmitter includes the control circuit 6 and the switch 9 and the combiner 5) of the embodiment, and a transmitter (for example, an amplifier 10 and an antenna 11 of the embodiment described later) that transmits the output signal of the selective combiner. The first spread modulation means is constituted by the SAW matched filter according to any one of claims 1 to 5, and the second spread modulation means at least constitutes the first spread modulation means. Depending on the distance that the surface acoustic wave propagates in a desired delay time obtained by adding the delay time between the input and output signals of the SAW matched filter and the first predetermined time, the positive and negative electrode finger pairs from the input electrode portion 6. The SAW matched filter according to claim 3, wherein the distance is determined, wherein the third spread modulation unit includes at least the second spread modulation unit. Resonating at the same resonance frequency as the SAW matched filter to be configured, and having a desired delay time obtained by adding the delay time between the input and output signals of the SAW matched filter constituting the first diffusion modulation means and the second predetermined time. The SAW matched filter according to any one of claims 3 to 5, wherein a distance from the input electrode portion of the positive / negative electrode finger pair is determined by a distance through which the surface acoustic wave propagates. It is characterized by.

  The transmitter having the above configuration is configured to spread the periodic pulse by the first code string by the first spread modulation means configured by the SAW matched filter according to any one of claims 1 to 5. In the case where the transmission data is converted to a reference signal which is a multiband according to the resonance frequency at which the SAW matched filter resonates and becomes a data determination reference, and the transmission data is the first level of the binary logic level. Since the periodic pulse is input to the second spread modulation means by the data control unit, at least the delay time between the input / output signals of the SAW matched filter constituting the first spread modulation means and the first predetermined time are added. The distance from the input electrode portion of the positive / negative electrode finger pair is determined in accordance with the distance that the surface acoustic wave propagates during the desired delay time. The periodic pulse is spectrum-spread by the second code string by any of the SAW matched filters and multibanded in accordance with the resonance frequency at which the SAW matched filter resonates. It is converted into a data signal having a different time and output.

Further, when the transmission data is the second level of the binary logic level, the periodic pulse is input to the third spread modulation means by the data control unit, so at least the SAW matched filter constituting the second spread modulation means The distance over which the surface acoustic wave propagates in a desired delay time that is the sum of the delay time between the input and output signals of the SAW matched filter constituting the first diffusion modulation means and the second predetermined time. The distance from the input electrode portion of the positive / negative electrode finger pair is determined according to the SAW matched filter according to any one of claims 3 to 5, wherein the periodic pulse is spectrumd by the second code string. Data that is diffused and multibanded according to the resonance frequency at which the SAW matched filter resonates differs from the reference signal by a second predetermined time. And outputs the conversion to the signal.
As a result, the binary pulse position modulation is performed based on the transmission data, and the data signal spectrum spread by the second code string and the reference signal spectrum spread by the first code string are multibanded. Can be transmitted as a spread spectrum signal.

  A receiver according to an eighth aspect of the invention is a receiver for receiving a spread spectrum signal, comprising the SAW matched filter according to any one of the first to fifth aspects.

  The receiver having the above configuration receives N spread spectrum signals by using the SAW matched filter according to any one of claims 1 to 5, so that N resonance frequencies at which the SAW matched filter resonates are obtained. Accordingly, it is possible to easily receive a spectrum signal multibanded into an N-wave signal.

  The receiver according to the ninth aspect of the invention receives a receiver (for example, an antenna 21, an amplifier 22 and a distributor 23 in an embodiment described later) for receiving and distributing a signal, and a signal distributed by the receiver. Then, a first spread demodulation means (for example, a SAW matched filter 24 of an embodiment described later) for detecting a reference signal spread by the first code string and outputting a reception timing of the reference signal; When a signal distributed by the receiving unit is input, a data signal spread by a second code string having the same speed and length as the first code string but having a different code arrangement is detected and Second spread demodulation means (for example, a SAW matched filter 25 of the embodiment described later) for outputting the reception timing of the data signal, and the reference signal output by the first spread demodulation means A delay time measurement unit (for example, in an embodiment to be described later) that calculates a delay time difference between the reference signal and the data signal by comparing the transmission timing with the reception timing of the data signal output from the second spread demodulation means. Based on a delay time difference between the delay time measuring unit 26) and the reference signal output from the delay time measuring unit and the data signal, the binary logic level is expressed by either the first level or the second level. A receiver including a data determination unit (for example, a data determination unit 27 in an embodiment described later) that outputs the received data, wherein the first spread demodulation means is any one of claims 1 to 5. And the second spread spectrum demodulator means at least a delay time between the SAW matched filter constituting the first spread spectrum demodulator and the input / output signal. There characterized in that it is constituted by a SAW matched filter according to claims 1, which is identical to any one of claims 5.

  The receiver having the above-described configuration is obtained by using the first code string from the input signal by the first spreading demodulator configured by the SAW matched filter according to any one of claims 1 to 5. 2. The delay time between the input / output signal and the SAW matched filter constituting the first spread demodulation means is the same while detecting the spread spectrum reference signal and outputting the reception timing of the reference signal. The SAW matched filter according to claim 5 detects a data signal spectrum-spread by the second code string from the input signal and outputs a reception timing of the data signal.

Then, the delay time measuring unit compares the reception timing of the reference signal output from the first spread demodulation means with the reception timing of the data signal output from the second spread demodulation means, and compares the reference signal and the data signal. A delay time difference is calculated, and is expressed by either the first level or the second level of the binary logic level based on the delay time difference between the reference signal output from the delay time measurement unit and the data signal by the data determination unit. Output received data.
Thereby, by matching the contents of the first and second code strings used for spread spectrum with the transmission side, and the correspondence between each code constituting the code string and the resonance frequency of the SAW matched filter, Based on a spread spectrum signal obtained by multi-banding a data signal that is subjected to binary pulse position modulation based on transmission data and spectrum-spread by the second code string and a reference signal spectrum-spread by the first code string The transmitted transmission data can be extracted.

According to the SAW matched filter of the first or second aspect, when the input signal is a wideband signal, a multiband spectrum signal can be output. On the other hand, when the input signal is a multi-band spread spectrum signal, the energy of the signal divided into N waves can be combined into one and the spread spectrum applied to the input signal can be despread. .
Therefore, by using this SAW matched filter for a transmitter or receiver, transmission or reception of a multiband wideband spectrum signal can be easily realized. In this case, it is possible to achieve an effect that it is possible to achieve both the extension of the transmission distance by improving the noise resistance of the signal and the reduction in power consumption, cost and size of the apparatus.

According to the SAW matched filter of the third aspect, the input signal can be delayed by an arbitrary time using the propagation time of the surface acoustic wave.
Therefore, by using a plurality of SAW matched filters with different delay times for the transmitter, it is possible to easily realize transmission of a wideband spectrum signal that is pulse position modulated. In communication using the ultra-wideband wireless communication system, it is possible to obtain an effect that the apparatus can be reduced in power consumption, cost, and size.

According to the SAW matched filter of the fourth aspect, the resonance frequency of the positive / negative electrode finger pair can be easily changed by the distance between the positive electrode finger and the negative electrode finger constituting the positive / negative electrode finger pair.
Accordingly, since SAW matched filters having different resonance frequencies can be easily manufactured, when transmitting / receiving a multi-band spread spectrum signal in communication using an ultra-wideband wireless communication system, the SAW matched filter can be used. Furthermore, the effect that the cost of the apparatus can be reduced can be obtained.

According to the SAW matched filter of the fifth aspect, by dispersing the energy of the input signal into a continuous signal at a predetermined frequency interval, the given frequency bandwidth can be used to the maximum extent possible.
Therefore, when transmitting / receiving a multi-band spread spectrum signal in communication using an ultra-wideband wireless communication system, the SAW matched filter is used to make the most efficient use of a given frequency bandwidth, thereby improving communication efficiency. The effect that it can raise is acquired.

According to the transmitter of the sixth aspect, it is possible to easily transmit a spectrum signal that is multibanded into an N-wave signal according to N resonance frequencies at which the SAW matched filter resonates.
Therefore, in the communication using the ultra-wideband wireless communication system, a transmitter that realizes both the extension of the transmission distance by improving the noise resistance of the signal and the reduction of the power consumption, the cost and the size of the apparatus can be realized. The effect of being able to be obtained.

According to the transmitter of claim 7, the binary pulse position modulation is performed based on the transmission data, and the data signal spectrum-spread by the second code string and the spectrum signal are spread by the first code string. The reference signal can be transmitted as a multi-band spread spectrum signal.
Therefore, in communication using the ultra-wideband wireless communication system using binary pulse position modulation, the transmission distance can be extended by improving the noise resistance of the signal, and the power consumption, cost and size of the device can be reduced. The effect that the transmitter to make compatible is realizable is acquired.

According to the receiver of the eighth aspect, it is possible to easily receive a spectrum signal that is multi-banded into an N-wave signal according to N resonance frequencies at which the SAW matched filter resonates.
Therefore, in communication using an ultra-wideband wireless communication system, to realize a receiver that achieves both the extension of the transmission distance by improving the noise resistance of the signal and the reduction in power consumption, cost and size of the device. The effect of being able to be obtained.

According to the receiver of claim 9, the binary pulse position modulation is performed based on the transmission data, and the data signal spread spectrum by the second code string and the spectrum signal spread by the first code string. Transmission data can be extracted from a spread spectrum signal obtained by converting the reference signal into a multiband.
Therefore, in communication using the ultra-wideband wireless communication system using binary pulse position modulation, the transmission distance can be extended by improving the noise resistance of the signal, and the power consumption, cost and size of the device can be reduced. An effect is achieved that a compatible receiver can be realized.

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

(Configuration of transmitter)
First, the configuration of a transmitter according to an embodiment of the present invention will be described. FIG. 1 is a block diagram showing the configuration of the transmitter of this embodiment. FIG. 1 shows a theoretical basic configuration of the transmitter for the sake of simplicity.
Specifically, in FIG. 1, a pulse generator 1 is a pulse generator that generates a periodic pulse having a wide band energy as shown in FIG. The pulse output from the pulse generator 1 is a periodic pulse that repeats a Gaussian monopulse as shown in FIG. 2 (a). The periodic pulse is distributed by the distributor 2, and one is input to the SAW matched filter 3. The other is input to the input terminal of the switch 4.

  Further, when a periodic pulse generated by the pulse generator 1 is input to the SAW matched filter 3, for example, the spectrum is spread by the code string PN 0 and multibanded into a four-band signal, for example, The output of the SAW matched filter 3 is input to a synthesizer 5 for synthesis with a data signal to be described later. Details of the SAW matched filter 3 will be described later.

  On the other hand, the switch 4 is a switch that outputs a signal input to one input terminal to one of the two output terminals by an external signal input to the control terminal. A control circuit 6 for driving the control terminal is connected to the control terminal of the switch 4, and the switch driven by the control circuit 6 according to the binary logic levels “0” and “1” of the transmission data. 4, for example, when the binary logic level of the transmission data is “0”, the periodic pulse generated by the pulse generator 1 is input to the SAW matched filter 7 connected to one output terminal. For example, when the binary logic level of the transmission data is “1”, the switch 4 inputs the periodic pulse generated by the pulse generator 1 to the SAW matched filter 8 connected to the other output terminal.

  When a periodic pulse generated by the pulse generator 1 is input via the switch 4 to the SAW matched filter 7, for example, the spectrum is generated by a code string PN1 having the same speed and length as the code string PN0 but having a different code arrangement. Spreading modulation means that also serves as a delay device that outputs a data signal that is delayed and time delayed by a time τ from the reference signal output from the SAW matched filter 3 that is spread and multi-banded into a 4-wave band signal, The output of the SAW matched filter 7 is input to the synthesizer 5 via the switch 9 in order to synthesize with the above-mentioned reference signal. Details of the SAW matched filter 7 will also be described later.

  On the other hand, when a periodic pulse generated by the pulse generator 1 is input via the switch 4 to the SAW matched filter 8, for example, the spectrum is generated by a code string PN1 having the same speed and length as the code string PN0 but having a different code arrangement. A spread modulation means that also serves as a delay device that outputs a data signal that is spread and multibanded into a 4-band signal and that is advanced by a time τ from the reference signal output by the SAW matched filter 3, The output of the SAW matched filter 8 is input to the synthesizer 5 via the switch 9 in order to synthesize with the above-described reference signal. Details of the SAW matched filter 8 will also be described later.

  The switch 9 is a switch that selects one of the signals input to the two input terminals by an external signal input to the control terminal and outputs the selected signal to one output terminal. Similarly to the switch 4, a control circuit 6 for driving the control terminal is connected to the control terminal of the switch 9, and the control circuit is adjusted in accordance with the binary logic levels “0” and “1” of the transmission data. For example, when the binary logic level of the transmission data is “0”, the switch 9 driven by 6 selects the output signal of the SAW matched filter 7 connected to one input terminal and inputs it to the combiner 5. For example, when the binary logic level of the transmission data is “1”, the switch 9 selects the output signal of the SAW matched filter 8 connected to the other input terminal and inputs it to the combiner 5. Thereby, pulse position modulation is performed on the data signal.

The combiner 5 is a combiner that combines the reference signal output from the SAW matched filter 3 and the data signal output from the SAW matched filter 7 selected by the switch 9 or the SAW matched filter 8 as described above. The signal synthesized by the synthesizer 5 is amplified by the amplifier 10 and transmitted from the antenna 11.
As a result, the transmitter according to the present embodiment can transmit a spectrum signal that is multibanded into four-wave signals as shown in FIG.

  Note that the above-described code string PN0 and code string PN1 are bit strings (pseudo-random noise) that simulate random noise having a correlation value peak periodically in autocorrelation and low correlation value in cross-correlation. In addition, the code string used for spread spectrum may be any series of codes as long as it is pseudo-random noise.

(Receiver configuration)
Next, the configuration of the receiver of this embodiment will be described. FIG. 3 is a block diagram showing the configuration of the receiver of this embodiment. FIG. 3 shows the theoretical basic configuration of the receiver for the sake of simplicity.
More specifically, in FIG. 3, the received signal input from the antenna 21 is amplified by the amplifier 22 and input to the distributor 23.
The distributor 23 is, for example, a distributor that distributes a signal input to one input terminal to two output terminals. A SAW matched filter 24 is connected to one output terminal of the distributor 23 to distribute the signal. A SAW matched filter 25 is connected to the other output terminal of the device 23.

  Further, when the received signal is input from the distributor 23, the SAW matched filter 24 detects a reference signal that is spectrum-spread by, for example, the code string PN0 and multibanded into a 4-wave signal, and detects the reference signal. A spread demodulation means for outputting reception timing, wherein the output of the SAW matched filter 24 compares the reception timing of the reference signal with the reception timing of a data signal, which will be described later, to determine the delay time difference between the reference signal and the data signal. This is input to the delay time measuring unit 26 to be calculated. Details of the SAW matched filter 24 will be described later.

  On the other hand, when the received signal is input from the distributor 23, the SAW matched filter 25 detects, for example, a data signal that is spectrum-spread by the code string PN1 and multi-banded into a 4-wave signal, and the SAW matched filter 24 The SAW matched filter 25 outputs the data signal reception timing with the same delay time as the output signal of the SAW matched filter 25 in order to compare the data signal reception timing with the reference signal reception timing described above. Input to the delay time measuring unit 26. Details of the SAW matched filter 25 will also be described later.

  In addition, the delay time difference between the reference signal output from the delay time measurement unit 26 and the data signal is input to the data determination unit 27, and the data determination unit 27 outputs the reference signal and the data signal output from the delay time measurement unit 26. On the basis of the delay time difference, the reception data represented by either “0” or “1” of the binary logic level is output. Specifically, on the transmitter side, for example, when the binary logical level of transmission data is “0”, the data signal is delayed by time τ from the reference signal, and the binary logical level of transmission data is “1”. In this case, assuming that the pulse position modulation is performed to advance the data signal by time τ from the reference signal, the delay time of the reference signal in the delay time difference between the reference signal output from the delay time measuring unit 26 and the data signal If the delay time of the data signal is larger, it is determined that data having a binary logic level of “0” has been received. If the delay time of the data signal is smaller than the delay time of the reference signal, the binary logic level is “1”. Is determined to have been received.

(Details of SAW matched filter 3)
Next, a detailed configuration of the SAW matched filter 3 used in the transmitter of this embodiment will be described. 4 and 5 are diagrams showing the configuration of the SAW matched filter 3 used in the transmitter of this embodiment. FIG. 4 shows a series configuration of the SAW matched filter 3 and FIG. 5 shows a parallel configuration of the SAW matched filter 3. Each configuration is shown.

(Serial configuration of SAW matched filter 3)
In FIG. 4, the serial configuration of the SAW matched filter 3 includes an input electrode portion S3A that excites a surface acoustic wave by an electrode S32 formed on the piezoelectric substrate S31, and one cycle time T of a code that forms a code string PN0. N positive and negative electrode finger pairs S331 to S33n arranged at right angles to the direction in which the surface acoustic wave propagates based on the distance through which the surface acoustic wave propagates and the number n of codes constituting the code string PN0, and the positive and negative The output electrode unit S3B includes positive and negative bipolar bus bars S36 and S37 to which the positive electrode fingers S341 to S34n and the negative electrode fingers S351 to S35n constituting the electrode finger pairs S331 to S33n are respectively connected.

  If the code string PN0 is a 15-bit code string of codes b1 to b15 expressed in binary numbers, 15 positive / negative electrode finger pairs are arranged in series, for example, 15 positive / negative electrode finger pairs arranged in series The sign and the positive / negative electrode finger pair are made to correspond one to one so that the positive / negative electrode finger pair S331 of S331 to S3315 corresponds to the sign b1 and the positive / negative electrode finger pair S3315 corresponds to the sign b15.

Further, the arrangement of the positive / negative electrode finger pairs S331 to S33n will be described in more detail. First, the positive / negative electrode finger pair S331 is moved from the electrode S32 of the input electrode portion S3A to an arbitrary time t1 (however, t1> τ). The surface acoustic wave is disposed at a distance D _t1 where the surface acoustic wave propagates. Further, the positive and negative electrode finger pairs S332 to S33n are respectively formed from the left positive / negative electrode finger pair, which is superior in the direction in which the surface acoustic wave propagates, during the one cycle time T of the code constituting the code string PN0. Is disposed at a distance _{DT through} which is propagated. That is, the positive / negative electrode finger pairs S332 to S33n are arranged at every distance D _{T in} which the surface acoustic wave propagates during one cycle time T from the positive / negative electrode finger pair S331.

  Further, the positive electrode fingers S341 to S34n and the negative electrode fingers S351 to S35n constituting the positive and negative electrode finger pairs S331 to S33n have a code polarity of “1” according to the content of the code string PN0, that is, the polarity of the code. In this case, the positive electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates. When the polarity of the code of the code string PN0 is “0”, the negative electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates.

  Specifically, the positive and negative electrode finger pairs S331, S332, S333, and S334 will be described as an example. The positive and negative electrode finger pairs S331 receive the surface acoustic wave first, and the negative electrode finger S351 later performs surface elasticity. Since the wave is received, it corresponds to the polarity “1” of the code of the code string PN0. Further, the positive / negative electrode finger pair S332 also corresponds to the sign polarity “1” of the code string PN0 because the positive electrode finger S342 receives the surface acoustic wave first and the negative electrode finger S352 receives the surface acoustic wave later.

  On the other hand, the positive / negative electrode finger pair S333 corresponds to the polarity “0” of the sign of the code string PN0 because the negative electrode finger S353 receives the surface acoustic wave first and the positive electrode finger S343 receives the surface acoustic wave later. The positive / negative electrode finger pair S334 corresponds to the sign polarity “1” of the code string PN0 because the positive electrode finger S344 receives the surface acoustic wave first and the negative electrode finger S354 receives the surface acoustic wave later.

  Furthermore, the distance between the positive electrode fingers S341 to S34n and the negative electrode fingers S351 to S35n constituting the positive and negative electrode finger pairs S331 to S33n is 1 based on the resonance frequency f at which the positive and negative electrode finger pairs S331 to S33n resonate. The distance L is set according to / f. For example, in the transmitter of the present embodiment, positive and negative electrode finger pairs S331 to S33n are shown in FIG. 15 in order to transmit a spectrum signal that has been converted into four bands arranged at equal intervals as shown in FIG. It is necessary to resonate with each of the center frequencies f1, f2, f3, and f4 of the four-wave signals arranged at equal intervals.

  Specifically, the positive and negative electrode finger pairs S331, S332, S333, and S334 will be described as an example. The positive and negative electrode finger pair S331 corresponds to, for example, the resonance frequency f1, and the distance between the positive electrode finger S341 and the negative electrode finger S351 is The distance L1 is set according to 1 / f1. Further, the positive / negative electrode finger pair S332 corresponds to, for example, the resonance frequency f2, and the distance between the positive electrode finger S342 and the negative electrode finger S352 is set to a distance L2 corresponding to 1 / f2. Further, the positive / negative electrode finger pair S333 is made to correspond to the resonance frequency f3, for example, and the distance between the positive electrode finger S343 and the negative electrode finger S353 is set to a distance L3 corresponding to 1 / f3.

  Also, the positive / negative electrode finger pair S334 is made to correspond to the resonance frequency f4, for example, and the distance between the positive electrode finger S344 and the negative electrode finger S354 is set to a distance L4 corresponding to 1 / f4. Further, by repeating this, resonance frequencies f1, f2, f3, and f4 are assigned to the positive and negative electrode finger pairs S335 to S33n, and the distances between the positive electrode fingers S345 to S34n and the negative electrode fingers S355 to S35n correspond respectively. L1, L2, L3, and L4 are set based on the resonance frequency.

  Therefore, as described above, if the code string PN0 is a 15-bit code string of codes b1 to b15 expressed in binary numbers, the SAW matched filter 3 includes the corresponding positive and negative electrode finger pairs S331 to S3315. Four positive and negative electrode finger pairs S331, S335, S339, and S3313 are assigned to the resonance frequency f1, and four positive and negative electrode finger pairs S332, S336, S3310, and S3314 are assigned to the resonance frequency f2, and the resonance frequency f3. Are assigned four positive / negative electrode finger pairs S333, S337, S3311, and S3315, and finally three positive / negative electrode finger pairs S334, S338, and S3312 are assigned to the resonance frequency f4.

(Parallel configuration of SAW matched filter 3)
In FIG. 5, the parallel configuration of the SAW matched filter 3 is arranged perpendicular to the input electrode portion P3A for exciting the surface acoustic wave by the electrode P32 formed on the piezoelectric substrate P31 and the direction in which the surface acoustic wave propagates. A pair of positive / negative electrode finger pairs and positive / negative bipolar bus bars to which the positive electrode fingers and the negative electrode fingers constituting the positive / negative electrode finger pairs are respectively connected are based on the number n of codes constituting the code string PN0. And n output electrodes P3B which are connected in parallel with each other to connect the positive-side bus bars to take out an output signal.

The output electrode portion P3B will be described in detail. One set of positive and negative electrode finger pairs P331 arranged perpendicular to the direction in which the surface acoustic wave propagates, and the positive electrode fingers P341 and the negative electrodes constituting the positive and negative electrode finger pairs P331 In the positive and negative bipolar bus bars P361 and P371 to which the finger P351 is connected, the positive and negative electrode finger pair P331 is at a time one time of one cycle time T of the code so as to correspond to the first code of the code string PN0. The surface acoustic wave is disposed at a position based on a distance _DT that propagates from the electrode P32 of the input electrode portion P3A.

Also, a pair of positive and negative electrode finger pairs P332 arranged perpendicular to the direction in which the surface acoustic wave propagates, and the positive and negative electrodes to which the positive electrode fingers P342 and the negative electrode fingers P352 constituting the positive and negative electrode finger pairs P332 are connected, respectively. In the bipolar bus bars P362 and P372, the positive and negative electrode finger pair P332 causes the surface acoustic wave to enter the input electrode portion P3A at a time twice as long as one cycle time T of the code so as to correspond to the second code of the code string PN0. It is arranged at a distance based on the 2D _T positions propagating from the electrode P32.

Similarly, a pair of positive and negative electrode finger pairs P33n arranged at right angles to the direction in which the surface acoustic wave propagates, and the positive electrode fingers P34n and the negative electrode fingers P35n constituting the positive and negative electrode finger pairs P33n are connected to each other. In the positive / negative bipolar bus bars P36n, P37n, the positive / negative electrode finger pair P33n causes the surface acoustic wave to be input at the time of n times the one cycle time T of the code so as to correspond to the nth code of the code string PN0. It is arranged at a position based on the distance nD _T propagating from the electrode P32 of the P3A.

  If the code string PN0 is a 15-bit code string of codes b1 to b15 expressed in binary numbers, a pair of positive and negative electrode finger pairs arranged perpendicular to the direction in which the surface acoustic wave propagates, and the positive and negative Fifteen positive / negative bipolar busbars connected to the positive and negative electrode fingers constituting the electrode finger pair are arranged in parallel, for example, the positive / negative electrode fingers of the positive / negative electrode finger pairs P331 to P3315 arranged in parallel. The sign and the positive / negative electrode finger pair are made to correspond one-to-one so that the pair P331 corresponds to the sign b1 and the positive / negative electrode finger pair P3315 corresponds to the sign b15.

Further, the arrangement of the positive / negative electrode finger pairs P331 to P33n will be described in more detail. First, the positive / negative electrode finger pair P331 is moved from the electrode P32 of the input electrode portion P3A during an arbitrary time t1 (however, t1> τ). The surface acoustic wave is disposed at a distance D _t1 (= D _T −α: where α = D _T −D _t1 ). Further, the positive / negative electrode finger pair P332 has a distance “D _t1 + D _T ” (= 2D _T −α: where α = D _T −) where the surface acoustic wave propagates from the input electrode portion P3A during the time “t1 + T”. D _t1 ). Similarly, the positive and negative electrode finger pair P33n has a distance “D _t1 + (n−1) × _DT where the surface acoustic wave propagates from the input electrode portion P3A during the time“ t1 + (n−1) × T ”. "(= ND _T -α: where α = D _T -D _t1 ).

  Similarly to the serial configuration of the SAW matched filter 3, the positive electrode fingers P341 to P34n and the negative electrode fingers P351 to P35n constituting the positive and negative electrode finger pairs P331 to P33n are determined according to the content of the code string PN0, that is, the polarity of the code. When the polarity of the code of the code string PN0 is “1”, the positive electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates. When the polarity of the code of the code string PN0 is “0”, the negative electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates.

  Furthermore, the distance between the positive electrode fingers P341 to P34n and the negative electrode fingers P351 to P35n constituting the positive and negative electrode finger pairs P331 to P33n is 1 based on the resonance frequency f at which the positive and negative electrode finger pairs P331 to P33n resonate. The distance L is set according to / f. For example, in the transmitter of this embodiment, in order to transmit a spectrum signal that has been converted into four bands arranged at equal intervals as shown in FIG. The electrode finger pairs P331 to P33n need to resonate with any one of the center frequencies f1, f2, f3, and f4 of the four-wave signals arranged at equal intervals shown in FIG.

  Specifically, similarly to the serial configuration of the SAW matched filter 3, resonance frequencies f1, f2, f3, and f4 are sequentially assigned to the positive and negative electrode finger pairs P331 to P33n, and the positive electrode fingers P341 to P34n and the negative electrode finger P351 are assigned. To P35n are set to L1, L2, L3, and L4 based on the corresponding resonant frequencies in order.

(Details of SAW matched filter 7)
Next, a detailed configuration of the SAW matched filter 7 used in the transmitter of this embodiment will be described. 6 and 7 are diagrams showing the configuration of the SAW matched filter 7 used in the transmitter of this embodiment. FIG. 6 shows the serial configuration of the SAW matched filter 7 and FIG. 7 shows the parallel configuration of the SAW matched filter 7. Each configuration is shown.

(Serial configuration of SAW matched filter 7)
In FIG. 6, the series configuration of the SAW matched filter 7 includes an input electrode portion S4A that excites a surface acoustic wave by an electrode S42 formed on a piezoelectric substrate S41, and one cycle time T of a code constituting the code string PN1. N positive and negative electrode finger pairs S431 to S43n arranged at right angles to the direction in which the surface acoustic wave propagates based on the distance through which the surface acoustic wave propagates and the number n of codes constituting the code string PN1, and the positive and negative The output electrode unit S4B includes positive and negative bipolar bus bars S46 and S47 to which the positive electrode fingers S441 to S44n and the negative electrode fingers S451 to S45n constituting the electrode finger pairs S431 to S43n are respectively connected.

  If the code string PN1 is a 15-bit code string of codes bb1 to bb15 expressed in binary numbers, 15 positive / negative electrode finger pairs are arranged in series, for example, 15 positive / negative electrode finger pairs arranged in series The sign and the positive / negative electrode finger pair are made to correspond one to one so that the positive / negative electrode finger pair S431 of S431 to S4315 corresponds to the sign bb1, and the positive / negative electrode finger pair S4315 corresponds to the sign bb15.

Further, the arrangement of the positive and negative electrode finger pairs S431 to S43n will be described in more detail. First, the positive and negative electrode finger pair S431 is moved from the electrode S42 of the input electrode portion S4A during a time “t1 + τ” (where t1> τ). The surface acoustic wave is disposed at a distance “D _t1 + D _τ ” through which the surface acoustic wave propagates. Further, the positive and negative electrode finger pairs S432 to S43n are respectively surface acoustic waves from the left positive / negative electrode finger pair, which are good in the direction in which the surface acoustic waves propagate, during one cycle time T of the code constituting the code string PN1. Is disposed at a distance _{DT through} which is propagated. That is, the positive and negative electrode finger pairs S432 to S43n are arranged for every distance D _{T at} which the surface acoustic wave propagates during one cycle time T from the positive and negative electrode finger pair S431.

  Further, the positive electrode fingers S441 to S44n and the negative electrode fingers S451 to S45n constituting the positive and negative electrode finger pairs S431 to S43n have a code polarity of “1” depending on the content of the code string PN1, that is, the polarity of the code. In this case, the positive electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates. Further, when the polarity of the code of the code string PN1 is “0”, the negative electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates.

  Specifically, the positive and negative electrode finger pairs S431, S432, S433, and S434 will be described as an example. In the positive and negative electrode finger pair S431, the positive electrode finger S441 receives the surface acoustic wave first, and the negative electrode finger S451 receives the surface elasticity later. Since the wave is received, it corresponds to the polarity “1” of the code of the code string PN1. Further, the positive / negative electrode finger pair S432 corresponds to the sign polarity “0” of the code string PN1 because the negative electrode finger S452 receives the surface acoustic wave first and the positive electrode finger S442 receives the surface acoustic wave later.

  On the other hand, the positive / negative electrode finger pair S433 also corresponds to the sign polarity “0” of the code string PN1 because the negative electrode finger S453 receives the surface acoustic wave first and the positive electrode finger S443 receives the surface acoustic wave later. The positive / negative electrode finger pair S434 corresponds to the polarity “1” of the code string PN1 because the positive electrode finger S444 receives the surface acoustic wave first and the negative electrode finger S454 receives the surface elastic wave later.

  Furthermore, the distance between the positive electrode fingers S441 to S44n and the negative electrode fingers S451 to S45n constituting the positive and negative electrode finger pairs S431 to S43n is 1 based on the resonance frequency f at which the positive and negative electrode finger pairs S431 to S43n resonate. The distance L is set according to / f. For example, in the transmitter of this embodiment, in order to transmit a spectrum signal that is multibanded into four-wave signals arranged at equal intervals as shown in FIG. 15, the positive and negative electrode finger pairs S431 to S43n are replaced with a SAW matched filter. 3, it is necessary to resonate with any one of the center frequencies f1, f2, f3, and f4 of the four-wave signals arranged at equal intervals shown in FIG.

  Specifically, similarly to the SAW matched filter 3, resonance frequencies f1, f2, f3, and f4 are sequentially assigned to the positive and negative electrode finger pairs S431 to S43n, and the positive electrode fingers S441 to S44n and the negative electrode fingers S451 to S45n Are set to L1, L2, L3, and L4 based on the corresponding resonance frequencies in order. However, at least the SAW matched filter 8 to be described later, the correspondence between the positive and negative electrode finger pairs corresponding to the code string PN1 and the resonance frequencies of the four waves are the same.

(Parallel configuration of SAW matched filter 7)
In FIG. 7, the parallel configuration of the SAW matched filter 7 is arranged perpendicular to the input electrode portion P4A for exciting the surface acoustic wave by the electrode P42 formed on the piezoelectric substrate P41 and the direction in which the surface acoustic wave propagates. A pair of positive / negative electrode finger pairs and positive / negative bipolar bus bars to which the positive electrode fingers and the negative electrode fingers constituting the positive / negative electrode finger pairs are respectively connected are based on the number n of codes constituting the code string PN1. In addition, n output electrodes are arranged in parallel, and a positive electrode bus bar P4B is connected to each other in order to extract an output signal.

The output electrode portion P4B will be described in detail. One set of positive and negative electrode finger pairs P431 arranged at right angles to the direction in which the surface acoustic wave propagates, and the positive electrode fingers P441 and the negative electrodes constituting the positive and negative electrode finger pairs P431 In the positive and negative bipolar bus bars P461 and P471 respectively connected to the finger P451, the positive / negative electrode finger pair P431 is at a time one time of one cycle time T of the code so as to correspond to the first code of the code string PN1. The surface acoustic wave is disposed at a position based on the distance _DT that propagates from the electrode P42 of the input electrode portion P4A.

Also, a pair of positive and negative electrode finger pairs P432 arranged perpendicular to the direction in which the surface acoustic wave propagates, and the positive and negative electrodes to which the positive electrode fingers P442 and the negative electrode fingers P452 constituting the positive and negative electrode finger pairs P432 are connected, respectively. In the bipolar bus bars P462 and P472, the positive and negative electrode finger pair P432 generates a surface acoustic wave at the input electrode portion P4A at a time twice as long as one cycle time T of the code so as to correspond to the second code of the code string PN1. It is arranged at a distance based on the 2D _T positions propagating from the electrode P42.

Similarly, a pair of positive / negative electrode finger pairs P43n arranged at right angles to the direction in which the surface acoustic wave propagates, and the positive electrode fingers P44n and the negative electrode fingers P45n constituting the positive / negative electrode finger pairs P43n are connected to each other. In the positive / negative bipolar bus bars P46n, P47n, the positive / negative electrode finger pair P43n generates the surface acoustic wave at the input electrode portion at time n times the one cycle time T of the code so as to correspond to the nth code of the code string PN1. It is arranged at a position based on the distance nD _T propagating from the electrode P42 of P4A.

  If the code string PN1 is a 15-bit code string of codes bb1 to bb15 expressed in binary numbers, a pair of positive and negative electrode finger pairs arranged perpendicular to the direction in which the surface acoustic wave propagates, and the positive and negative Fifteen positive / negative bipolar busbars connected to the positive and negative electrode fingers constituting the electrode finger pair are arranged in parallel, for example, the positive / negative electrode fingers of the positive / negative electrode finger pairs P431 to P4315 arranged in parallel, for example. The sign and the positive / negative electrode finger pair are made to correspond one-to-one so that the pair P431 corresponds to the sign bb1 and the positive / negative electrode finger pair P4315 corresponds to the sign bb15.

Further, the arrangement of the positive / negative electrode finger pairs P431 to P43n will be described in more detail. First, the positive / negative electrode finger pair P431 is moved from the electrode P42 of the input electrode portion P4A during the time “t1 + τ” (where t1> τ). The surface acoustic wave is disposed at a distance “D _t1 + D _τ ” (= D _T −α + D _τ : where α = D _T −D _t1 ). Further, the positive / negative electrode finger pair P432 has a distance “D _t1 + D _T + D _τ ” (= 2D _T −α + D _τ) where the surface acoustic wave propagates from the input electrode portion P4A during the time “t1 + T + _τ ” (where α = D _T -D _t1 ). Similarly, the positive / negative electrode finger pair P43n has a distance “D _t1 + (n−1) × _DT where the surface acoustic wave propagates from the input electrode portion P4A during the time“ t1 + (n−1) × T + τ ”. _{+ D τ "(= nD T} -α + D τ: where, α ₌ D T _{-D t1)} is disposed.

  Similarly to the serial configuration of the SAW matched filter 7, the positive electrode fingers P441 to P44n and the negative electrode fingers P451 to P45n constituting the positive and negative electrode finger pairs P431 to P43n are determined according to the content of the code string PN1, that is, the polarity of the code. When the polarity of the code of the code string PN1 is “1”, the positive electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates. Further, when the polarity of the code of the code string PN1 is “0”, the negative electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates.

  Furthermore, the distance between the positive electrode fingers P441 to P44n and the negative electrode fingers P451 to P45n constituting the positive and negative electrode finger pairs P431 to P43n is 1 based on the resonance frequency f at which the positive and negative electrode finger pairs P431 to P43n resonate. The distance L is set according to / f. For example, in the transmitter of this embodiment, in order to transmit a spectrum signal that has been converted into four bands arranged at equal intervals as shown in FIG. 15, a pair of positive and negative electrode fingers P431 to P43n is used as a SAW matched filter. 3, it is necessary to resonate with any one of the center frequencies f1, f2, f3, and f4 of the four-wave signals arranged at equal intervals shown in FIG.

  Specifically, similarly to the serial configuration of the SAW matched filter 7, resonance frequencies f1, f2, f3, and f4 are sequentially assigned to the positive and negative electrode finger pairs P431 to P43n, and the positive electrode fingers P441 to P44n and the negative electrode finger P451 are assigned. To P45n are set to L1, L2, L3, and L4 based on the corresponding resonance frequencies in order. However, at least the SAW matched filter 8 to be described later, the correspondence between the positive and negative electrode finger pairs corresponding to the code string PN1 and the resonance frequencies of the four waves are the same.

(Details of SAW matched filter 8)
Next, a detailed configuration of the SAW matched filter 8 used in the transmitter of this embodiment will be described. 8 and 9 are diagrams showing the configuration of the SAW matched filter 8 used in the transmitter of this embodiment. FIG. 8 shows the serial configuration of the SAW matched filter 8 and FIG. 9 shows the parallel configuration of the SAW matched filter 8. Each configuration is shown.

(Serial configuration of SAW matched filter 8)
In FIG. 8, the SAW matched filter 8 has a series configuration in which an input electrode portion S5A that excites a surface acoustic wave by an electrode S52 formed on a piezoelectric substrate S51, and one cycle time T of a code constituting the code string PN1. N positive and negative electrode finger pairs S531 to S53n arranged at right angles to the direction in which the surface acoustic wave propagates based on the distance through which the surface acoustic wave propagates and the number n of codes constituting the code string PN1, and the positive and negative It comprises an output electrode portion S5B having positive and negative bipolar bus bars S56 and S57 to which positive electrode fingers S541 to S54n and negative electrode fingers S551 to S55n constituting the electrode finger pairs S531 to S53n are respectively connected.

  If the code string PN1 is a 15-bit code string of codes bb1 to bb15 expressed in binary numbers, 15 positive / negative electrode finger pairs are arranged in series, for example, 15 positive / negative electrode finger pairs arranged in series The sign and the positive / negative electrode finger pair are made to correspond one-to-one so that the positive / negative electrode finger pair S531 of S531 to S5315 corresponds to the code bb1, and the positive / negative electrode finger pair S5315 corresponds to the code bb15.

Further, the arrangement of the positive / negative electrode finger pairs S531 to S53n will be described in more detail. First, the positive / negative electrode finger pair S531 is moved from the electrode S52 of the input electrode portion S5A for a time “t1-τ” (where t1> τ). It is arranged at a distance “D _t1 -D _τ ” through which surface acoustic waves propagate. Further, the positive and negative electrode finger pairs S532 to S53n are respectively surface acoustic waves from the left positive / negative electrode finger pair, which are good in the direction in which the surface acoustic waves propagate, during one cycle time T of the code constituting the code string PN1. Is disposed at a distance _{DT through} which is propagated. That is, the positive and negative electrode finger pairs S532 to S53n are arranged for each distance D _{T at} which the surface acoustic wave propagates during one cycle time T from the positive and negative electrode finger pair S531.

  Similarly to the SAW matched filter 7, the positive electrode fingers S541 to S54n and the negative electrode fingers S551 to S55n constituting the positive and negative electrode finger pairs S531 to S53n are represented by the code string PN1 according to the contents of the code string PN1, that is, the sign polarity. When the polarity of the sign of “1” is “1”, the positive electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates. Further, when the polarity of the code of the code string PN1 is “0”, the negative electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates.

Furthermore, the distance between the positive electrode fingers S541 to S54n and the negative electrode fingers S551 to S55n constituting the positive and negative electrode finger pairs S531 to S53n is 1 based on the resonance frequency f at which the positive and negative electrode finger pairs S531 to S53n resonate. The distance L is set according to / f.
Specifically, similarly to the SAW matched filter 7, resonance frequencies f1, f2, f3, and f4 are sequentially assigned to the positive and negative electrode finger pairs S531 to S53n, and the positive electrode fingers S541 to S54n and the negative electrode fingers S551 to S55n Are set to L1, L2, L3, and L4 based on the corresponding resonance frequencies in order. Note that at least a transmitter uses a code string PN1 to generate a spectrum signal that is multibanded into four-wave signals, a SAW matched filter 7, a positive / negative electrode finger pair corresponding to the code string PN1, and a four-wave resonance frequency. Must be the same.

(Parallel configuration of SAW matched filter 8)
In FIG. 9, the parallel configuration of the SAW matched filter 8 is arranged perpendicular to the input electrode portion P5A for exciting the surface acoustic wave by the electrode P52 formed on the piezoelectric substrate P51 and the direction in which the surface acoustic wave propagates. A pair of positive / negative electrode finger pairs and positive / negative bipolar bus bars to which the positive electrode fingers and the negative electrode fingers constituting the positive / negative electrode finger pairs are respectively connected are based on the number n of codes constituting the code string PN1. And n output electrodes P5B connected to each other on the positive side bus bar for taking out an output signal.

The output electrode portion P5B will be described in detail. One set of positive and negative electrode finger pairs P531 arranged at right angles to the direction in which the surface acoustic wave propagates, and the positive electrode fingers P541 and the negative electrodes constituting the positive and negative electrode finger pairs P531 In the positive and negative bipolar bus bars P561 and P571 respectively connected to the finger P551, the positive / negative electrode finger pair P531 corresponds to the first code of the code string PN1 at a time that is one time of one cycle time T of the code. The surface acoustic wave is disposed at a position based on the distance _DT that propagates from the electrode P52 of the input electrode portion P5A.

Further, a pair of positive and negative electrode finger pairs P532 arranged at right angles to the direction in which the surface acoustic wave propagates, and positive and negative electrodes to which the positive electrode fingers P542 and the negative electrode fingers P552 constituting the positive and negative electrode finger pairs P532 are connected, respectively. In the bipolar bus bars P562 and P572, the positive and negative electrode finger pair P532 generates the surface acoustic wave at the input electrode portion P5A at a time twice the one cycle time T of the code so as to correspond to the second code of the code string PN1. It is arranged at a distance based on the 2D _T positions propagating from the electrode P52.

Similarly, a pair of positive / negative electrode finger pairs P53n arranged at right angles to the direction in which the surface acoustic wave propagates, and the positive electrode fingers P54n and the negative electrode fingers P55n constituting the positive / negative electrode finger pairs P53n are respectively connected. In the positive / negative bipolar bus bars P56n, P57n, the positive / negative electrode finger pair P53n causes the surface acoustic wave to be input at the time of n times the one cycle time T of the code so as to correspond to the nth code of the code string PN1. It is arranged at a position based on the distance nD _T propagating from the electrode P52 of P5A.

  If the code string PN1 is a 15-bit code string of codes bb1 to bb15 expressed in binary numbers, a pair of positive and negative electrode finger pairs arranged perpendicular to the direction in which the surface acoustic wave propagates, and the positive and negative Fifteen positive / negative bipolar busbars each connecting the positive electrode finger and the negative electrode finger constituting the electrode finger pair are arranged in parallel, for example, the positive / negative electrode fingers of the positive / negative electrode finger pairs P531 to P5315 arranged in parallel The sign and the positive / negative electrode finger pair are made to correspond one-to-one so that the pair P531 corresponds to the sign bb1 and the positive / negative electrode finger pair P5315 corresponds to the sign bb15.

Further, the arrangement of the positive / negative electrode finger pairs P531 to P53n will be described in more detail. First, the positive / negative electrode finger pair P531 is moved from the electrode P52 of the input electrode portion P5A for a time “t1-τ” (where t1> τ). It is arranged at a distance “D _t1 −D _τ ” (= D _T −α−D _τ : where α = D _T −D _t1 ) between which surface acoustic waves propagate. Further, the positive / negative electrode finger pair P532 has a distance “D _t1 + D _T −D _τ ” (= 2D _T −α−D _τ) where the surface acoustic wave propagates from the input electrode portion P5A during the time “t1 + T−τ”. : Provided that α = D _T −D _t1 ). Similarly, the positive / negative electrode finger pair P53n has a distance “D _t1 + (n−1) × where the surface acoustic wave propagates from the input electrode portion P5A during the time“ t1 + (n−1) × T−τ ”. D _T -D _τ ″ (= nD _T -α-D _τ : where α = D _T -D _t1 ).

  Similarly to the SAW matched filter 7, the positive electrode fingers P541 to P54n and the negative electrode fingers P551 to P55n constituting the positive and negative electrode finger pairs P531 to P53n are represented by the code string PN1 according to the content of the code string PN1, that is, the polarity of the code. When the polarity of the sign of “1” is “1”, the positive electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates. Further, when the polarity of the code of the code string PN1 is “0”, the negative electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates.

Furthermore, the distance between the positive electrode fingers P541 to P54n and the negative electrode fingers P551 to P55n constituting the positive and negative electrode finger pairs P531 to P53n is 1 based on the resonance frequency f at which the positive and negative electrode finger pairs P531 to P53n resonate. The distance L is set according to / f.
Specifically, similarly to the SAW matched filter 7, resonance frequencies f1, f2, f3, and f4 are sequentially assigned to the positive and negative electrode finger pairs P531 to P53n, and the positive electrode fingers P541 to P54n and the negative electrode fingers P551 to P55n Are set to L1, L2, L3, and L4 based on the corresponding resonance frequencies in order. Note that at least a transmitter uses a code string PN1 to generate a spectrum signal that is multibanded into four-wave signals, a SAW matched filter 7, a positive / negative electrode finger pair corresponding to the code string PN1, and a four-wave resonance frequency. Must be the same.

  Therefore, in the transmitter of the present embodiment, the spectrum is generated by the code string PN0 as shown in the upper part of FIG. 10 from the SAW matched filter 3 configured in series or in parallel to which the periodic pulse generated by the pulse generator 1 is input. While being spread, a transmission impulse train is output as a reference signal assigned to the resonance frequencies f1, f2, f3, and f4. For example, when the binary logic level of the transmission data is “0”, the switch 4 selects the SAW matched filter 7 and inputs the periodic pulse generated by the pulse generator 1. As shown in the middle part of FIG. 10, the matched filter 7 spreads the spectrum by the code string PN1, and is assigned to the resonance frequencies f1, f2, f3, and f4, and further as a data signal delayed by time τ from the reference signal. A transmission impulse train is output.

  Similarly, for example, when the binary logic level of the transmission data is “1”, the switch 4 selects the SAW matched filter 8 and inputs the periodic pulse generated by the pulse generator 1. As a data signal spread from the SAW matched filter 8 by the code string PN1 as shown in the lower part of FIG. 10 and assigned to the resonance frequencies f1, f2, f3, and f4 and further advanced by the time τ from the reference signal. The transmission impulse train is output. For example, when the binary logic level of the transmission data is “0”, the switch 9 selects the output of the SAW matched filter 7, and this is combined with the reference signal output by the SAW matched filter 3 in the combiner 5. Send. Similarly, for example, when the binary logic level of the transmission data is “1”, the switch 9 selects the output of the SAW matched filter 8, and this is combined with the reference signal output by the SAW matched filter 3 in the combiner 5. To send. In addition, FIG. 10 is a figure which shows the output signal of the SAW matched filter used for the transmitting apparatus of a present Example.

(Details of SAW matched filter 24)
Next, a detailed configuration of the SAW matched filter 24 used in the receiver of this embodiment will be described. 11 and 12 are diagrams showing the configuration of the SAW matched filter 24 used in the receiver of this embodiment. FIG. 11 shows the serial configuration of the SAW matched filter 24, and FIG. 12 shows the parallel configuration of the SAW matched filter 24. Each configuration is shown.

(Serial configuration of SAW matched filter 24)
In FIG. 11, the SAW matched filter 24 has a series configuration in which an input electrode portion S6A that excites a surface acoustic wave by an electrode S62 formed on a piezoelectric substrate S61, and one cycle time T of a code constituting the code string PN0. N positive and negative electrode finger pairs S631 to S63n arranged at right angles to the direction in which the surface acoustic wave propagates based on the distance through which the surface acoustic wave propagates and the number n of codes constituting the code string PN0, and the positive and negative It comprises an output electrode section S6B having positive and negative bipolar bus bars S66 and S67 to which positive electrode fingers S641 to S64n and negative electrode fingers S651 to S65n constituting the electrode finger pairs S631 to S63n are respectively connected.

  If the code string PN0 is a 15-bit code string of codes b1 to b15 expressed in binary numbers, 15 positive / negative electrode finger pairs are arranged in series, for example, 15 positive / negative electrode finger pairs arranged in series The sign and the positive / negative electrode finger pair are made to correspond one to one so that the positive / negative electrode finger pair S631 of S631 to S6315 corresponds to the sign b1 and the positive / negative electrode finger pair S6315 corresponds to the sign b15.

Further, the arrangement of the positive / negative electrode finger pairs S631 to S63n will be described in more detail. First, the positive / negative electrode finger pair S631 has a distance at which surface acoustic waves propagate from the electrode S62 of the input electrode portion S6A during an arbitrary time t2. It is arranged at _Dt2 . Further, the positive and negative electrode finger pairs S632 to S63n are respectively surface acoustic waves from a positive / negative electrode finger pair on the left side, which is better in the direction in which the surface acoustic waves propagate, during one cycle time T of the code constituting the code string PN0. Is disposed at a distance _{DT through} which is propagated. That is, the positive / negative electrode finger pairs S632 to S63n are arranged for each distance D _{T at} which the surface acoustic wave propagates during one cycle time T from the positive / negative electrode finger pair S631.

  Similarly to the SAW matched filter 3, the positive electrode fingers S641 to S64n and the negative electrode fingers S651 to S65n constituting the positive and negative electrode finger pairs S631 to S63n are represented by the code string PN0 according to the contents of the code string PN0, that is, the polarity of the code. When the polarity of the sign of “1” is “1”, the positive electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates. When the polarity of the code of the code string PN0 is “0”, the negative electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates.

Furthermore, the distance between the positive electrode fingers S641 to S64n and the negative electrode fingers S651 to S65n constituting the positive and negative electrode finger pairs S631 to S63n is 1 based on the resonance frequency f at which the positive and negative electrode finger pairs S631 to S63n resonate. The distance L is set according to / f.
Specifically, similarly to the SAW matched filter 3, the resonance frequencies f1, f2, f3, and f4 are sequentially assigned to the positive and negative electrode finger pairs S631 to S63n, and the positive electrode fingers S641 to S64n and the negative electrode fingers S651 to S65n Are set to L1, L2, L3, and L4 based on the corresponding resonance frequencies in order. It should be noted that at least a transmitter uses a code string PN0 to generate a spectrum signal multibanded into four-wave signals, a SAW matched filter 3, a positive / negative electrode finger pair corresponding to the code string PN0, and a four-wave resonance frequency. Must be the same.

(Parallel configuration of SAW matched filter 24)
In FIG. 12, the parallel configuration of the SAW matched filter 24 is arranged at right angles to the input electrode portion P6A for exciting the surface acoustic wave by the electrode P62 formed on the piezoelectric substrate P61 and the direction in which the surface acoustic wave propagates. A pair of positive / negative electrode finger pairs and positive / negative bipolar bus bars to which the positive electrode fingers and the negative electrode fingers constituting the positive / negative electrode finger pairs are respectively connected are based on the number n of codes constituting the code string PN0. And n output electrodes P6B, which are connected in parallel with each other and the positive-side bus bars are connected to each other in order to take out an output signal.

The output electrode portion P6B will be described in detail. One set of positive and negative electrode finger pairs P631 arranged perpendicular to the direction in which the surface acoustic wave propagates, and the positive electrode fingers P641 and the negative electrodes constituting the positive and negative electrode finger pairs P631 In the positive and negative bipolar bus bars P661 and P671 to which the finger P651 is connected, the positive and negative electrode finger pair P631 is at a time that is one time of one cycle time T of the code so as to correspond to the first code of the code string PN0. The surface acoustic wave is disposed at a position based on the distance _DT that propagates from the electrode P62 of the input electrode portion P6A.

Further, a pair of positive and negative electrode finger pairs P632 arranged perpendicular to the direction in which the surface acoustic wave propagates, and positive and negative electrodes to which the positive electrode fingers P642 and the negative electrode fingers P652 constituting the positive and negative electrode finger pairs P632 are connected, respectively. In the bipolar bus bars P662 and P672, the positive and negative electrode finger pair P632 generates a surface acoustic wave at the input electrode part P6A at a time twice as long as one cycle time T of the code so as to correspond to the second code of the code string PN0. It is arranged at a distance based on the 2D _T positions propagating from the electrode P62.

Similarly, a pair of positive and negative electrode finger pairs P63n arranged perpendicular to the direction in which the surface acoustic wave propagates, and the positive electrode fingers P64n and the negative electrode fingers P65n constituting the positive and negative electrode finger pairs P63n are connected to each other. In the positive and negative bipolar bus bars P66n and P67n, the positive and negative electrode finger pair P63n generates the surface acoustic wave at the input electrode portion at a time n times the one cycle time T of the code so as to correspond to the nth code of the code string PN0. It is arranged at a position based on the distance nD _T propagating from P6A electrode P62.

  If the code string PN0 is a 15-bit code string of codes bb1 to bb15 expressed in binary numbers, a pair of positive and negative electrode finger pairs arranged perpendicular to the direction in which the surface acoustic wave propagates, and the positive and negative Fifteen positive / negative bipolar busbars connected to the positive electrode finger and the negative electrode finger constituting the electrode finger pair are arranged in parallel, for example, the positive / negative electrode fingers of the positive / negative electrode finger pairs P631 to P6315 arranged in parallel, for example. The sign and the positive / negative electrode finger pair are made to correspond one-to-one so that the pair P631 corresponds to the sign bb1 and the positive / negative electrode finger pair P6315 corresponds to the sign bb15.

Further, the arrangement of the positive / negative electrode finger pairs P631 to P63n will be described in more detail. First, the positive / negative electrode finger pair P631 is a distance at which the surface acoustic wave propagates from the electrode P62 of the input electrode portion P6A during an arbitrary time t2. It is arranged at D _t2 (= D _T −β: where β = D _T −D _t2 ). Further, the positive / negative electrode finger pair P632 has a distance “D _t2 + D _T ” (= 2D _T −β: where β = D _T − where the surface acoustic wave propagates from the input electrode portion P6A during the time “t2 + T”. D _t2 ). Similarly, the positive / negative electrode finger pair P63n has a distance “D _t2 + (n−1) × D _{T from} which the surface acoustic wave propagates during the time“ t2 + (n−1) × T ”from the input electrode portion P6A. "(= ND _T -β: where β = D _T -D _t2 ).

  Similarly to the SAW matched filter 3, the positive electrode fingers P641 to P64n and the negative electrode fingers P651 to P65n constituting the positive and negative electrode finger pairs P631 to P63n are represented by the code string PN0 according to the contents of the code string PN0, that is, the polarity of the code. When the polarity of the sign of “1” is “1”, the positive electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates. When the polarity of the code of the code string PN0 is “0”, the negative electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates.

Further, the distance between the positive electrode fingers P641 to P64n and the negative electrode fingers P651 to P65n constituting the positive and negative electrode finger pairs P631 to P63n is 1 based on the resonance frequency f at which the positive and negative electrode finger pairs P631 to P63n resonate. The distance L is set according to / f.
Specifically, similarly to the SAW matched filter 3, resonance frequencies f1, f2, f3, and f4 are sequentially assigned to the positive and negative electrode finger pairs P631 to P63n, and the positive electrode fingers P641 to P64n and the negative electrode fingers P651 to P65n Are set to L1, L2, L3, and L4 based on the corresponding resonance frequencies in order. It should be noted that at least a transmitter uses a code string PN0 to generate a spectrum signal multibanded into four-wave signals, a SAW matched filter 3, a positive / negative electrode finger pair corresponding to the code string PN0, and a four-wave resonance frequency. Must be the same.

(Details of SAW matched filter 25)
Next, a detailed configuration of the SAW matched filter 25 used in the receiver of this embodiment will be described. 13 and 14 are diagrams showing the configuration of the SAW matched filter 25 used in the receiver of this embodiment. FIG. 13 shows the serial configuration of the SAW matched filter 25, and FIG. 14 shows the parallel configuration of the SAW matched filter 25. Each configuration is shown.

(Serial configuration of SAW matched filter 25)
In FIG. 13, the serial configuration of the SAW matched filter 25 includes an input electrode portion S7A that excites a surface acoustic wave by an electrode S72 formed on a piezoelectric substrate S71, and one cycle time T of a code constituting the code string PN1. N positive and negative electrode finger pairs S731 to S73n arranged at right angles to the direction in which the surface acoustic wave propagates based on the distance through which the surface acoustic wave propagates and the number n of codes constituting the code string PN1, and the positive and negative It comprises an output electrode section S7B having positive and negative bipolar bus bars S76 and S77 to which positive electrode fingers S741 to S74n and negative electrode fingers S751 to S75n constituting the electrode finger pairs S731 to S73n are respectively connected.

  If the code string PN1 is a 15-bit code string of codes bb1 to bb15 expressed in binary numbers, 15 positive / negative electrode finger pairs are arranged in series, for example, 15 positive / negative electrode finger pairs arranged in series The sign and the positive / negative electrode finger pair are made to correspond one-to-one so that the positive / negative electrode finger pair S731 of S731 to S7315 corresponds to the code bb1, and the positive / negative electrode finger pair S7315 corresponds to the code bb15.

Further, the arrangement of the positive / negative electrode finger pairs S731 to S73n will be described in more detail. First, the positive / negative electrode finger pair S731 starts from the electrode S72 of the input electrode portion S7A and has a surface elasticity during the time t2 as in the SAW matched filter 24. It is arranged at a distance D _t2 where the wave propagates. In addition, the positive and negative electrode finger pairs S732 to S73n each have a surface acoustic wave from the left positive / negative electrode finger pair that is superior to the direction in which the surface acoustic wave propagates during one cycle time T of the code constituting the code string PN1. Is disposed at a distance DT through which the signal propagates. In other words, the positive and negative electrode finger pairs S732 to S73n are arranged for each distance D _T through which the surface acoustic wave propagates during one cycle time T from the positive and negative electrode finger pair S731.

  Similarly to the SAW matched filters 7 and 8, the positive electrode fingers S741 to S74n and the negative electrode fingers S751 to S75n constituting the positive and negative electrode finger pairs S731 to S73n are encoded according to the content of the code string PN1, that is, the polarity of the code. When the polarity of the sign of the column PN1 is “1”, the positive electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates. Further, when the polarity of the code of the code string PN1 is “0”, the negative electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates.

Further, the distance between the positive electrode fingers S741 to S74n and the negative electrode fingers S751 to S75n constituting the positive and negative electrode finger pairs S731 to S73n is 1 based on the resonance frequency f at which the positive and negative electrode finger pairs S731 to S73n resonate. The distance L is set according to / f.
Specifically, similarly to the SAW matched filters 7 and 8, the resonance frequencies f1, f2, f3, and f4 are sequentially assigned to the positive and negative electrode finger pairs S731 to S73n, and the positive electrode fingers S741 to S74n and the negative electrode finger S751 are assigned. The distances from S75n are set to L1, L2, L3, and L4 based on the corresponding resonant frequencies in order. It should be noted that at least a transmitter uses a code string PN1 to generate a spectrum signal multibanded into four-wave signals, a SAW matched filter 7 or SAW matched filter 8, a positive / negative electrode finger pair corresponding to the code string PN1, and 4 The correspondence with the resonant frequency of the wave must be the same.

(Parallel configuration of SAW matched filter 25)
In FIG. 14, the parallel configuration of the SAW matched filter 25 is arranged perpendicular to the input electrode portion P7A for exciting the surface acoustic wave by the electrode P72 formed on the piezoelectric substrate P71 and the direction in which the surface acoustic wave propagates. A pair of positive / negative electrode finger pairs and positive / negative bipolar bus bars to which the positive electrode fingers and the negative electrode fingers constituting the positive / negative electrode finger pairs are respectively connected are based on the number n of codes constituting the code string PN1. In addition, n output electrodes are arranged in parallel, and a positive electrode bus bar P7B is connected to each other in order to extract an output signal.

The output electrode portion P7B will be described in detail. One set of positive and negative electrode finger pairs P731 arranged at right angles to the direction in which the surface acoustic wave propagates, and the positive electrode fingers P741 and the negative electrodes constituting the positive and negative electrode finger pairs P731 In the positive and negative bipolar bus bars P761 and P771 to which the finger P751 is connected, the positive / negative electrode finger pair P731 is at a time one time of one cycle time T of the code so as to correspond to the first code of the code string PN1. The surface acoustic wave is disposed at a position based on the distance _DT that propagates from the electrode P72 of the input electrode portion P7A.

Also, a pair of positive and negative electrode finger pairs P732 arranged perpendicular to the direction in which the surface acoustic wave propagates, and the positive and negative electrodes to which the positive electrode fingers P742 and the negative electrode fingers P752 constituting the positive and negative electrode finger pairs P732 are connected, respectively. In the bipolar busbars P762 and P772, the positive and negative electrode finger pair P732 generates the surface acoustic wave at the input electrode portion P7A at a time twice the one cycle time T of the code so as to correspond to the second code of the code string PN1. It is arranged at a distance based on the 2D _T positions propagating from the electrode P72.

Similarly, a pair of positive and negative electrode finger pairs P73n arranged perpendicular to the direction in which the surface acoustic wave propagates, and the positive electrode fingers P74n and the negative electrode fingers P75n constituting the positive and negative electrode finger pairs P73n are connected to each other. In the positive / negative bipolar bus bars P76n, P77n, the positive / negative electrode finger pair P73n generates the surface acoustic wave at the input electrode portion at time n times the one cycle time T of the code so as to correspond to the nth code of the code string PN1. It is arranged at a position based on the distance nD _T propagating from P7A electrode P72.

  If the code string PN1 is a 15-bit code string of codes bb1 to bb15 expressed in binary numbers, a pair of positive and negative electrode finger pairs arranged perpendicular to the direction in which the surface acoustic wave propagates, and the positive and negative Fifteen positive / negative bipolar busbars connected to the positive electrode finger and the negative electrode finger constituting the electrode finger pair are arranged in parallel, for example, the positive / negative electrode fingers of the positive / negative electrode finger pairs P731 to P7315 arranged in parallel, for example. The sign and the positive / negative electrode finger pair are made to correspond one-to-one so that the pair P731 corresponds to the sign bb1 and the positive / negative electrode finger pair P7315 corresponds to the sign bb15.

Further, the arrangement of the positive / negative electrode finger pairs P731 to P73n will be described in more detail. First, the positive / negative electrode finger pair P731 starts from the electrode P72 of the input electrode portion P7A and has surface elasticity during the time t2 as in the SAW matched filter 24. It is arranged at a distance D _t2 (= D _T −β: where β = D _T −D _t2 ) where the wave propagates. Further, the positive / negative electrode finger pair P732 has a distance “D _t2 + D _T ” (= 2D _T −β: where β = D _T − where the surface acoustic wave propagates from the input electrode part P7A during the time “t2 + T”. D _t2 ). Similarly, positive and negative electrode finger pairs P73n from the input electrode section P7A, time "t2 + (n-1) × T" distance surface acoustic wave propagates between the _{"D t2 + (n-1} ) × D T "(= ND _T -β: where β = D _T -D _t2 ).

  Similarly to the SAW matched filters 7 and 8, the positive electrode fingers P741 to P74n and the negative electrode fingers P751 to P75n constituting the positive and negative electrode finger pairs P731 to P73n are coded according to the content of the code string PN1, that is, the polarity of the code. When the polarity of the sign of the column PN1 is “1”, the positive electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates. Further, when the polarity of the code of the code string PN1 is “0”, the negative electrode finger is arranged on the left side, which is better than the direction in which the surface acoustic wave propagates.

Furthermore, the distance between the positive electrode fingers P741 to P74n and the negative electrode fingers P751 to P75n constituting the positive and negative electrode finger pairs P731 to P73n is 1 based on the resonance frequency f at which the positive and negative electrode finger pairs P731 to P73n resonate. The distance L is set according to / f.
Specifically, similarly to the SAW matched filters 7 and 8, the resonance frequencies f1, f2, f3, and f4 are sequentially assigned to the positive and negative electrode finger pairs P731 to P73n, and the positive electrode fingers P741 to P74n and the negative electrode fingers P751 to P751. The distances between P75n are set to L1, L2, L3, and L4 based on the corresponding resonance frequencies in order. It should be noted that at least a transmitter uses a code string PN1 to generate a spectrum signal multibanded into four-wave signals, a SAW matched filter 7 or SAW matched filter 8, a positive / negative electrode finger pair corresponding to the code string PN1, and 4 The correspondence with the resonant frequency of the wave must be the same.

  Therefore, in the receiver of the present embodiment, the SAW matched filter 24 configured in series or in parallel is transmitted to a transmission impulse train as a reference signal as shown in FIG. 10A and FIG. 10B or FIG. When a combined signal of the reference signal as shown in c) and a transmission impulse train as a data signal whose time differs by time τ is input, the SAW matched filter 24 is spread spectrum by the code train PN0 and four waves, for example. A reference signal that has been converted into a multiband signal is detected and the reception timing of the reference signal is output to the delay time measurement unit 26.

  Similarly, a transmission impulse train as a reference signal as shown in FIG. 10 (a) and a reference as shown in FIG. 10 (b) or FIG. 10 (c) are applied to a SAW matched filter 25 configured in series or parallel. When a composite signal of a signal and a transmission impulse train as a data signal having a time different by the time τ is input, the SAW matched filter 25 is spread-spectrum by, for example, the code train PN1 and multibanded into a 4-wave signal. The received data signal is detected, and the reception timing of the data signal is output to the delay time measuring unit 26 with the same delay time as the SAW matched filter 24. Then, based on the delay time difference between the reference signal output from the delay time measurement unit 26 and the data signal, the data determination unit 27 converts the received data represented by either “0” or “1” of the binary logic level. Output.

  In this embodiment, the spread spectrum code sequence applied to the reference signal between the transmitter and the receiver is “PN0”, and the frequencies to be multiband are frequencies f1, f2 that are continuous at a predetermined interval. , F3, and f4, the spread spectrum code string applied to the data signal is “PN1”, and the frequencies to be multibanded are the continuous frequencies f1, f2, f3, and f4 at predetermined intervals. However, between the transmitter and the receiver, the spread spectrum code sequence applied to the reference signal, and the correspondence between the positive and negative electrode finger pairs corresponding to the code sequence and the plurality of resonance frequencies are the same, Similarly, a condition that the spread spectrum code sequence applied to the data signal and the correspondence between the positive and negative electrode finger pairs corresponding to the code sequence and the plurality of resonance frequencies are the same between the transmitter and the receiver. As long as the above conditions are satisfied, the following configuration changes are allowed in the SAW matched filter, the transmitter, and the receiver.

  Specifically, first, the SAW matched filters 3, 7, 8, 24, and 25 may be realized by either a serial configuration or a parallel configuration. Further, in one transmitter, one receiver, or one transmission / reception system including the transmitter and receiver of this embodiment, the SAW matched filters 3, 7, 8, 24, and 25 have a series configuration. It is not necessary to unify either one of the parallel configurations, and the serial configuration and the parallel configuration may be mixed.

  In addition, the number of frequencies to be multibanded may be any number as long as it is two or more. On the other hand, the frequency to be multibanded may not be a frequency that is continuous at a predetermined interval. Therefore, for example, only the resonance frequencies f1 and f4 described in this embodiment may be used. Furthermore, it is preferable that the reference signal and the data signal have the same multiband frequency so that the transmission characteristics between the transmitter and the receiver are the same, but the multiband frequency is not necessarily the same. For example, the reference signal is assigned to the resonance frequencies f1 and f2 described in this embodiment, and the data signal is assigned to the resonance frequencies f3 and f4 described in this embodiment. The data signal may be allocated separately.

  Further, the positive and negative electrode finger pairs corresponding to the spread spectrum code string are associated with a plurality of resonance frequencies in the order of f1, f2, and f3 from the top of the positive and negative electrode finger pairs as in the SAW matched filter of this embodiment. , F4, f1, f2,..., F1, f1, f1,..., F1, f1,. It is possible to associate them in any order so as to repeat f1, f2, f2, f2, f3, f3, f3.

  Similarly, since the positive / negative electrode finger pair only needs to resonate at any one of the resonance frequencies, for example, according to the resonance frequency of four waves, 15 corresponding to a 15-bit code string, as in the SAW matched filter of the present embodiment. There is no need to correspond three positive and negative electrode finger pairs to the resonance frequency f1, three to the resonance frequency f2, three to the resonance frequency f3, and two to the resonance frequency f4, and corresponds to a 15-bit code string. In such a way, the 15 positive and negative electrode finger pairs are associated with, for example, 6 at the resonance frequency f1, 6 at the resonance frequency f2, 2 at the resonance frequency f3, and 1 at the resonance frequency f4. You may associate. Note that the insertion loss can be reduced when the number of positive and negative electrode finger pairs is small.

  Further, in the transmitter of the present embodiment, when the data signal is subjected to pulse position modulation, the data signal is delayed by the time τ with respect to the reference signal to represent the binary logic level “0” of the transmission data, The binary logic level “1” of the transmission data is represented by advancing the data signal by time τ with respect to the reference signal. For example, by delaying the data signal by time 3τ with respect to the reference signal, the transmission data 2 The binary logic level of the transmission data is represented as “0” of the value logic level, while “1” of the binary logic level of the transmission data is represented by delaying the data signal by time τ with respect to the reference signal. If the delay time difference of the pulse train of the data signal representing “0” and “1” of the data signal can be distinguished from the reference signal, the reference signal and the data signal can be used within a range in which the transmission data rate (bit rate) is not lowered. Delay time difference may be to some.

  Further, for example, by delaying the data signal with respect to the reference signal by the time τ, the binary logic level “1” of the transmission data is represented. On the other hand, by transmitting the data signal with respect to the reference signal by the time τ, the transmission data The binary logic level “0” and “1” of the transmission data and the correspondence of the pulse in the pulse position modulation are matched between the transmitter and the receiver so as to represent “0” of the binary logic level of As long as the mark is removed, it may be associated in any way.

  Furthermore, in the parallel configuration example of the SAW matched filter of the present embodiment, the positive and negative electrode finger pairs arranged in parallel are shown in the order of the signs of the desired code string in order from the top of the figure. The distance at which the surface acoustic wave propagates from the input electrode portion in a time M times the one cycle time of the code so as to correspond one-to-one to the Mth code (M is an integer equal to or greater than 1) As long as they are arranged based on each other, the order of the positive and negative electrode finger pairs arranged in parallel may not be the order of the signs.

  As described above, the transmitter according to the present embodiment inputs the periodic pulse generated by the pulse generator 1 to the SAW matched filter 3 and is spread spectrum by, for example, the code string PN0 and multiband into four band signals. A reference signal serving as a data determination reference is generated by the SAW matched filter 3 that outputs the converted signal. On the other hand, for example, when the binary logic level of the transmission data is “0”, the periodic pulse generated by the pulse generator 1 is input to the SAW matched filter 7, and the code sequence PN0 has the same speed and length as the code arrangement, for example. Is delayed by the time τ from the reference signal generated by the SAW matched filter 3 by the SAW matched filter 7 that outputs a signal that is spectrum-spread by different code strings PN1 and multibanded into four band signals. A signal is generated and transmitted with the reference signal.

  For example, when the binary logic level of the transmission data is “1”, the periodic pulse generated by the pulse generator 1 is input to the SAW matched filter 8, and for example, the code sequence PN0 has the same speed and length as the code arrangement. Is advanced by time τ from the reference signal generated by the SAW matched filter 3 by the SAW matched filter 8 that outputs a signal that is spectrum-spread by different code sequences PN1 and multibanded into four band signals. A signal is generated and transmitted with the reference signal.

  On the other hand, when the received signal is input, the receiver according to the present embodiment includes, for example, the SAW matched filter 24 that detects a reference signal that is spectrum-spread by the code string PN0 and multibanded into a 4-wave signal. The reception timing of the reference signal is detected. Similarly, when a reception signal is input, the reception timing of the data signal is detected by the SAW matched filter 25 that detects, for example, a data signal that is spectrum-spread by the code string PN1 and multibanded into a 4-wave signal. Is detected. Then, the delay time measurement unit 26 calculates a delay time difference between the reference signal and the data signal, and based on the delay time difference, the data determination unit 27 expresses either a binary logic level “0” or “1”. Output received data.

  Therefore, using a SAW matched filter that does not require power between the transmitter and the receiver, using a simple configuration, the reference signal spread by the code string PN0 and 2 based on the transmission data. Improve signal noise resistance in ultra-wideband wireless communication systems by transmitting and receiving four-wave signals with original pulse position modulated and spread spectrum data signal by code string PN1. Thus, it is possible to achieve both the extension of the transmission distance due to the low power consumption, the low cost, and the miniaturization of the transmitter or the receiver.

  Specifically, for example, when the standard of the transmission power density of the ultra-wideband wireless communication system is -41.3 [dBm / MHz] or less, all the positive and negative electrode finger pairs are resonated at the resonance frequency f1 to be a single band. The amplitude satisfying the standard is A. As in the transmitter of this embodiment, the SAW matched filters 3, 7, and 8, for example, according to the resonance frequency of 4 waves, 15 positive and negative electrode finger pairs corresponding to a 15-bit code string are When the frequency is 3 for f1, 3 for the resonance frequency f2, 3 for the resonance frequency f3, and 2 for the resonance frequency f4, the average power density of the signal having the resonance frequency f1 as the center frequency is 4/15. Therefore, it becomes about 5.7 [dB] lower. Therefore, in order to set the average power density to −41.3 [dBm / MHz], the amplitude of the transmission pulse can be about 1.93 times the amplitude A described above.

Similarly, the average power density of the signal having the resonance frequencies f2 and f3 as the center frequency is also 4/15. Therefore, in order to set the average power density to −41.3 [dBm / MHz], the amplitude of the transmission pulse is set as described above. The amplitude A can be about 1.93 times. Further, since the average power density of the signal having the resonance frequency f4 as the center frequency is 3/15, in order to set the average power density to −41.3 [dBm / MHz], the amplitude of the transmission pulse is set to the amplitude A described above. Can be about 2.24 times greater.
Therefore, since the maximum amplitude of the time axis waveform is increased, the transmitted pulse is less likely to be buried in noise at the receiving end, and the effect that the communication transmission distance can be extended is obtained.

  The SAW matched filter of the present embodiment, and the transmitter and receiver using the SAW matched filter can be used not only for communication by the ultra-wideband wireless communication system but also for transmitters and receivers for any wired or wireless communication. it can.

It is a block diagram which shows the structure of the transmitter of one Example of this invention. It is a figure which shows the pulse which the pulse generator 1 used for the transmitter of the Example outputs, and its energy distribution. It is a block diagram which shows the structure of the receiver of the Example. It is a figure which shows the serial structure of the SAW matched filter 3 used for the transmitting apparatus of the Example. It is a figure which shows the parallel structure of the SAW matched filter 3 used for the transmitting apparatus of the Example. It is a figure which shows the serial structure of the SAW matched filter 7 used for the transmitting apparatus of the Example. It is a figure which shows the parallel structure of the SAW matched filter 7 used for the transmitter of the Example. It is a figure which shows the serial structure of the SAW matched filter 8 used for the transmitting apparatus of the Example. It is a figure which shows the parallel structure of the SAW matched filter 8 used for the transmitting apparatus of the Example. It is a figure which shows the output signal of the SAW matched filter used for the transmitting apparatus of the Example. It is a figure which shows the serial structure of the SAW matched filter 24 used for the receiver of the Example. It is a figure which shows the parallel structure of the SAW matched filter 24 used for the receiver of the Example. It is a figure which shows the serial structure of the SAW matched filter 25 used for the receiver of the Example. It is a figure which shows the parallel structure of the SAW matched filter 25 used for the receiver of the Example. It is a figure which shows the frequency spectrum of the signal made into multiband. It is a figure which shows the frequency spectrum of the conventional signal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pulse generator, 2, 23 ... Distributor, 3, 7, 8, 24, 25 ... SAW matched filter, 4, 9 ... Switch, 5 ... Synthesizer, 6. ..Control circuit 10, 22 ... Amplifier, 11, 21 ... Antenna, 26 ... Delay time measurement unit, 27 ... Data determination unit, S31, S41, S51, S61, S71, P31, P41, P51, P61, P71 ... Piezoelectric substrate, S32, S42, S52, S62, S72, P32, P42, P52, P62, P72 ... Electrodes, S3A, S4A, S5A, S6A, S7A, P3A, P4A, P5A, P6A, P7A ... Input electrode section, S3B, S4B, S5B, S6B, S7B, P3B, P4B, P5B, P6B, P7B ... Output electrode section, S331-S33n, S431-S 3n, S531 to S53n, S631 to S63n, S731 to S73n, P331 to P33n, P431 to P43n, P531 to P53n, P631 to P63n, P731 to P73n: Positive and negative electrode finger pairs, S341 to S34n, S441 to S44n, S541 -S54n, S641-S64n, S741-S74n, P341-P34n, P441-P44n, P541-P54n, P641-P64n, P741-P74n ... Positive electrode fingers, S351-S35n, S451-S45n, S551-S55n, S651 -S65n, S751-S75n, P351-P35n, P451-P45n, P551-P55n, P651-P65n, P751-P75n ... Negative electrode finger, S36, S46, S56, S66, S76, P361-P 6n, P461-P46n, P561-P56n, P661-P66n, P761-P76n ... Positive bus bar, S37, S47, S57, S67, S77, P371-P37n, P471-P47n, P571-P57n, P671-P67n, P771-P77n: Negative electrode bus bar

Claims (9)

An input electrode portion for exciting a surface acoustic wave by an electrode formed on a piezoelectric substrate;
Based on the distance that the surface acoustic wave propagates in one cycle time of the code constituting the desired code string and the number of codes constituting the code string, a plurality of the surface acoustic waves propagated at right angles In a SAW matched filter comprising: a positive / negative electrode finger pair; and an output electrode unit including a positive / negative bipolar bus bar to which the positive electrode finger and the negative electrode finger constituting the positive / negative electrode finger pair are connected,
Each of the positive and negative electrode finger pairs has a one-to-one correspondence with the polarity of the code in the order of the codes constituting the code string, and resonates at one of N different resonance frequencies (N is an integer of 2 or more). A SAW matched filter characterized by: An input electrode portion for exciting a surface acoustic wave by an electrode formed on a piezoelectric substrate;
A pair of positive and negative electrode finger pairs arranged at right angles to the direction in which the surface acoustic wave propagates, and positive and negative bipolar bus bars to which the positive electrode fingers and the negative electrode fingers constituting the positive and negative electrode finger pairs are respectively connected; A SAW matched filter comprising a plurality of electrodes arranged in parallel based on the number of codes constituting the code string, and an output electrode portion to which the bus bars on the positive electrode side are connected to each other to extract an output signal. And
The positive and negative electrode finger pairs respectively correspond to the polarity of the Mth code so that the Mth code (M is an integer of 1 or more) of the desired code string has a one-to-one correspondence. The surface acoustic wave is arranged on the basis of the distance that the surface acoustic wave propagates from the input electrode portion at a time M times one cycle time, and resonates at any one of N different resonance frequencies (N is an integer of 2 or more). A SAW matched filter characterized by: The distance from the said electrode part for said input of the said positive / negative electrode finger pair is determined by the distance which the said surface acoustic wave propagates in the desired delay time between input-output signals, or Claim The SAW matched filter according to 2. The SAW matched filter according to any one of claims 1 to 3, wherein a resonance frequency of the positive / negative electrode finger pair is determined by a distance between the positive electrode finger and the negative electrode finger. The SAW matched filter according to any one of claims 1 to 4, wherein the resonance frequency is continuous at a predetermined frequency interval. In a transmitter for transmitting a spread spectrum signal,
A transmitter comprising the SAW matched filter according to any one of claims 1 to 5. A pulse generator for generating periodic pulses;
When the periodic pulse is input, first spread modulation means for outputting a reference signal serving as a data determination reference that is spectrum-spread by the first code string;
When the periodic pulse is input, the first code string is spectrum spread by a second code string having the same speed and length as the first code string but having a different code arrangement, and the reference signal and the first predetermined time period. Second spread modulation means for outputting data signals having different times only;
When the periodic pulse is input, third spread modulation means for spectrum-spreading by the second code string and outputting a data signal whose time differs from the reference signal by a second predetermined time;
When the transmission data is the first level of the binary logic level, the periodic pulse is input to the second spread modulation means, and when the transmission data is the second level of the binary logic level, the periodic pulse is A data control unit for inputting to the third spread modulation means;
When the transmission data is the first level of the binary logic level, the output of the second spread modulation means is selected and combined with the output signal of the first spread modulation means, and the transmission data is binary. In the case of the second level of the logic level, a selection combining unit that selects the output of the third spread modulation unit and combines it with the output signal of the first spread modulation unit;
A transmitter including a transmission unit that transmits an output signal of the selection combining unit,
The first spread modulation means is constituted by the SAW matched filter according to any one of claims 1 to 5,
The second spread modulation means has at least the surface elasticity at a desired delay time obtained by adding the delay time between the input and output signals of the SAW matched filter constituting the first spread modulation means and the first predetermined time. The SAW matched filter according to any one of claims 3 to 5, wherein a distance from the input electrode portion of the positive / negative electrode finger pair is determined by a distance through which a wave propagates,
The third spread modulation means resonates at least at the same resonance frequency as the SAW matched filter constituting the second spread modulation means, and the input / output signal of the SAW matched filter constituting the first spread modulation means. The distance from the input electrode portion of the positive / negative electrode finger pair is determined by a distance by which the surface acoustic wave propagates during a desired delay time obtained by adding the delay time between and the second predetermined time. A transmitter comprising the SAW matched filter according to any one of claims 3 to 5. In a receiver for receiving a spread spectrum signal,
A receiver comprising the SAW matched filter according to any one of claims 1 to 5. A receiver for receiving and distributing signals;
A first spread demodulation means for detecting a reference signal spread spectrum by the first code string and outputting a reception timing of the reference signal when a signal distributed by the receiving unit is input;
When a signal distributed by the receiving unit is input, a data signal spread by a second code string having the same speed and length as the first code string but having a different code arrangement is detected. Second spreading demodulation means for outputting the reception timing of the data signal;
A delay time difference between the reference signal and the data signal by comparing the reception timing of the reference signal output from the first spread demodulation means with the reception timing of the data signal output from the second spread demodulation means A delay time measuring unit for calculating
Data for outputting received data represented by either a first or second level of a binary logic level based on a delay time difference between the reference signal and the data signal output by the delay time measurement unit A receiver including a determination unit,
The first spread demodulation means is constituted by the SAW matched filter according to any one of claims 1 to 5,
The SAW according to any one of claims 1 to 5, wherein the second spread spectrum demodulator has at least the same delay time between the input / output signals as the SAW matched filter constituting the first spread spectrum demodulator. A receiver comprising a matched filter.

Images