JPH05251989A - Processing unit for correlation of surface acoustic waves - Google Patents

Abstract

PURPOSE:To obtain the surface acoustic wave correlation processing unit with a high efficiency without increasing its chip size. CONSTITUTION:Plural guide paths 4 are arranged between at least a couple of interdigital electrodes 2, 3 converting an electric signal into a surface acoustic wave and a distance (p) between the guide paths 4 and phases of surface acoustic waves stimulated from each guide path 4 are selected so that the surface acoustic wave stimulated by each guide path 4 is propagated in phase as a whole in a direction of an output interdigital electrode 5 with respect to the guide path 4 and propagated in opposite phase as a whole to an opposite side to the output interdigital electrode 5 with respect to the guide path 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface acoustic wave correlation processing device which utilizes surface acoustic waves to perform correlation processing between an input signal and a reference signal.

[0002]

2. Description of the Related Art FIG. 10 is a plan view showing a surface acoustic wave convolver which is a conventional surface acoustic wave correlation processing device disclosed in Japanese Patent Laid-Open No. 2-48812. In FIG.
Reference numeral 1 is a piezoelectric body, and 2 and 3 are surface acoustic waves (hereinafter, SAW).
Is an input IDT (hereinafter abbreviated as input IDT), 4 is a waveguide, and 5 is an output IDT that converts the SAW excited in the waveguide 4 into an electric signal. Hereinafter, it is abbreviated as an output IDT). Each of the input IDTs 2 and 3 and the output IDT 5 has a positive electrode 6
The negative electrode 7 and the negative electrode 7 intersect each other. 8
Is a SAW excited by the input IDT 2, 9 is a SAW excited by the input IDT 3, and 10 is a SAW excited in the waveguide 4.

Next, the operation of the conventional SAW convolver of this type will be described. The SAW convolver has a function of performing a correlation calculation between the input signal and the reference signal and outputting the calculation result. In the SAW convolver shown in FIG. 10, for example, an input signal is input to the input IDT 2,
The reference signal is input to the input IDT 3 for use. When a signal is input to the input IDT 2, the SAW 8 is excited at the location where the positive electrode 6 and the negative electrode 7 of the input IDT 2 intersect. The SAW 8 excited by the input IDT 2 and the SAW 9 excited by the input IDT 3 cross in the waveguide 4 and propagate in opposite directions.

At this time, in the waveguide 4, the mixing operation of the SAWs 8 and 9 occurs due to the nonlinearity in the waveguide 4. That is, the product F · Amplitude F of the amplitude F of the SAW8 from the input IDT2 and the amplitude G of the SAW9 from the input IDT3
G occurs. Since the waveguide 4 is made of a conductor, the potential created by this product F · G is integrated over the length L. The amplitudes F and G of the SAWs 8 and 9 incident on the waveguide 4 are represented by the following equations.

Amplitude F = f · EXP [j (ω ₁ t−k ₁ X)] (1) Amplitude G = g · EXP [j (ω ₂ t−k ₂ (L−X))] (2)

Here, f and g are input IDTs, respectively.
2 and SAW excited by input IDT3
Absolute values of amplitudes 8 and 9, ω ₁ and ω ₂ are respective angular frequencies, k ₁ k ₂ is each wave number, L is the length of the waveguide 4,
X is a coordinate value along the propagation direction of the SAW 8 where one end of the waveguide 4 is zero. The calculation result H obtained by integrating the product of these F and G over the length L is as shown in the following expression (3).

[0007]

[Equation 1]

As a result, the waveguide 4 has an angular frequency (ω ₁ +
It vibrates at ω ₂ ) and again excites the SAW 10 at this angular frequency (ω ₁ + ω ₂ ). The SAW 10 excited in the waveguide 4 is the calculation result H in the waveguide 4.
Which corresponds to the correlation calculation result between the input signal and the reference signal. These processes are described in the literature, Nakagawa, Makio, IEICE Transactions, '86 / 2, VoI.
J69-C, No. 2, p. 190-198.

At this time, the arrangement interval p of the waveguides 4 is set to an integral multiple of the wavelength of the SAW 10 excited in the waveguides 4, so that the SAWs 10 excited in each waveguide 4 are propagated in the propagation direction. As a result, the output IDT 5 can receive the SAW 10 excited from each waveguide 4.

SAW 10 excited by each waveguide 4
Is bidirectional and propagates in the direction in which the output IDT 5 is arranged and in the direction opposite to the output IDT 5 with respect to the waveguide 4. Therefore, as shown in FIG. 10, the output ID
When T5 is arranged only in one direction in which the SAW 10 excited in each of the waveguides 4 propagates, T5 is excited in each of the waveguides 4 in the direction opposite to the output IDT 5 with respect to each of the waveguides 4. The propagating SAW 10 becomes useless power that is not received by the output IDT 5. For this reason,
In another conventional surface acoustic wave convolver of this type shown in Japanese Patent No. 48812, as shown in FIG. 11, by arranging a waveguide 4 between a plurality of output IDTs 5a, 5b, each of the above waveguides is arranged. All the electric power of the SAW 10 excited from the waveguide 4 was received. In the case of having a plurality of output IDTs 5a and 5b as shown in FIG.
The outputs of the plurality of output IDTs 5a and 5b are externally connected.

Further, as a conventional surface acoustic wave convolver of this type disclosed in Japanese Patent Laid-Open No. 2-48812,
There is one shown in FIG. This is a structure in which the positive electrode 6 and the negative electrode 7 of the input IDT 2 for exciting the SAW are bent along the arrangement direction of the waveguides 4 without changing the electrode distance d. In the conventional SAW convolver of this type, the positive electrode 6 and the negative electrode 7 are displaced by a distance corresponding to 1/2 of the wavelength of the SAW 8 excited by the input IDT 2. This is because the phase of the SAW 8 incident on each waveguide 4 is changed by shifting the position of the intersection that excites the SAW.

As a result, in the conventional surface acoustic wave convolver of this type, the phase of the SAW 10 excited in each waveguide 4 becomes opposite between the adjacent waveguides 4. Furthermore, the arrangement interval p of the adjacent waveguides 4 is the SAW excited by the waveguides 4.
The arrangement was such that p = (1/2 + n) · λ for 10 wavelengths λ. Here, n is an integer.

For this reason, the adjacent waveguides 4 excite the SAWs 10 in opposite phases, and the phases are inverted by the time the excited SAWs 10 propagate to the adjacent waveguides 4, so that each waveguide 4 is eventually inverted. The SAWs 10 excited at are in phase with each other along the propagation direction. Therefore, the output IDT
At 5, all SAWs 10 excited by the respective waveguides 4 are received in phase.

[0014]

The SAW convolver of this type, which is a conventional surface acoustic wave correlation processing apparatus, has the configuration shown in FIG.
0, and as shown in FIG. 12, in the case where the output IDT 5 is arranged on only one side of the propagation direction of the SAW 10 excited in the waveguide 4, it is excited from the waveguide 4. Since only half the power of the SAW 10 can be received, the SAW convolver has a problem of poor efficiency. Further, as shown in FIG. 11, in the case of the configuration in which the waveguide 4 is arranged between the plurality of output IDTs 5a and 5b in order to receive all the SAW 10 excited from the waveguide 4, the SAW convolver is used. There is a problem in that the pattern area is increased, the chip size is increased, and a means for electrically connecting a plurality of output IDTs 5a and 5b arranged apart is required.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a surface acoustic wave correlation processing apparatus having high efficiency without increasing the chip size.

[0016]

A surface acoustic wave correlation processing apparatus according to the present invention is formed on a piezoelectric body and has at least a pair of first and second electric signals for converting a first electric signal and a second electric signal into surface acoustic waves. One electrode and a second electrode, propagate the first surface acoustic wave and the second surface acoustic wave respectively excited from the first electrode and the second electrode in opposite directions,
A plurality of waveguides having nonlinearity that mixes the first surface acoustic wave and the second surface acoustic wave to excite the third surface acoustic wave, and the waveguide provided on one side of the waveguide. And a third electrode for converting the third surface acoustic wave excited into an electric signal into an electric signal, wherein the array spacing of the plurality of waveguides and the surface acoustic wave excitation phase are excited in each of the plurality of waveguides. , The surface acoustic waves propagating in the direction of the third electrode are synthesized in the same phase, and the surface acoustic waves propagating in the direction opposite to the third electrode are synthesized in such a phase that they cancel each other. Is set to.

[0017]

In the surface acoustic wave correlation processing apparatus according to the present invention, the arrangement interval of the plurality of waveguides and the surface acoustic wave excitation phase are excited in each of the plurality of waveguides and provided on one side of the waveguides. The surface acoustic waves propagating in the direction of the third electrode are synthesized in the same phase, and the surface acoustic waves propagating in the direction opposite to the third electrode are synthesized in a phase that cancels each other to a predetermined value. Since the surface acoustic wave excited by each of the above-mentioned waveguides has almost all the electric power propagated in the direction of the third electrode and the surface acoustic wave is received by the third electrode, this type of conventional The efficiency is higher than that of the surface acoustic wave correlation processing device. Further, unlike the conventional surface acoustic wave correlation processing apparatus of this type, it is not necessary to dispose the output electrodes on both sides of the waveguide, so that the chip size is not increased.

[0018]

EXAMPLES Example 1. FIG. 1 is a plan view showing a surface acoustic wave correlation processing apparatus according to an embodiment of the present invention. In the figure, 1 is a piezoelectric body, 2a, 2b, 2c, 3a, 3b, 3c
Is an input interdigital transducer for converting an input signal into a surface acoustic wave, 4a, 4b, 4c is a waveguide, 5 is an output interdigital transducer, and the input interdigital electrodes 2a, 2b, 2c, 3 are shown.
The positive electrodes 6 and the negative electrodes 7 of the a, 3b, 3c and the output interdigital transducers 5 have a structure intersecting each other. 8a, 8b and 8c are surface acoustic waves converted by the input interdigital transducers 2a, 2b and 2c, and 9a, 9b and 9c are elastic surfaces converted by the input interdigital transducers 3a, 3b and 3c, respectively. Waves, 10a
Is a surface acoustic wave excited by the waveguide 4b and propagating to the opposite side of the output interdigital transducer 5 with respect to the waveguide 4b.
b is a surface acoustic wave excited by the waveguide 4b and propagating toward the output interdigital transducer 5 with respect to the waveguide 4b.
c is a surface acoustic wave excited by the waveguide 4a and propagating in the same direction as the surface acoustic wave 10b.

Next, the operation will be described. In the first embodiment shown in FIG. 1, the array spacing p between the waveguides 4a, 4b, 4c is p.
Is excited by the waveguides 4a, 4b, 4c.
It is arranged so as to satisfy p to (1/4 + n) · λ with respect to the wavelength λ of W. Here, n is an integer. further,
SAW 8a, 8 incident on each waveguide 4a, 4b, 4c
The phases of b, 8c, 9a, 9b, and 9c are changed, and the phase of the SAW excited in each of the waveguides 4a, 4b, and 4c is changed. For example, in the example shown in FIG.
When the phase of a is 180 °, the phase of the waveguide 4b is 90 °, and the phase of the waveguide 4c is 0 °, the SAW 8 is incident on each of the waveguides 4a, 4b, and 4c so as to excite the SAW.
The phases of a, 8b, 8c, 9a, 9b and 9c are changed. As a means for this, in the example shown in FIG. 1, the input ID
T2a, 2b, 2c are divided into waveguides 4a, 4
By changing the distance between b and 4c, the phase of SAW8a is 180 °, the phase of SAW8b is 90 °, and the phase of SAW8c is SAW8c.
Is set to 0 °. That is, the waveguides 4b and 4c
The input IDT 2b is set by setting the difference between the distance between the input IDT 2b and the waveguide 4b and the distance between the input IDT 2c and the waveguide 4c by an amount corresponding to the phase difference of about 90 ° between the SAWs 8b and 8c incident on the input IDT 2b. 2c are arranged. Input IDT
The difference in the distance between the waveguides 2a and 2c and the waveguides 4a and 4b is set in the same manner. Moreover, the distances between the input IDTs 3a, 3b, 3c and the waveguides 4a, 4b, 4c are all the same, and SA
The phases of W9a, 9b, and 9c are all 0 °.

The waveguide 4b is excited by the waveguide 4b.
The phase of the SAW 10a that has propagated to a is 90 ° during excitation, and changes by −90 ° as it propagates, resulting in 0 ° on the waveguide 4a. On the other hand, the waveguide 4a
The phase of the SAW excited on the waveguide 4a is 180 ° because the propagation distance is zero, and the SAW excited on the waveguide 4a and the SAW1 excited on the waveguide 4b are
0a cancels each other. On the other hand, the phase of the SAW 10c excited in the waveguide 4a and propagating to the waveguide 4c is 180 ° during excitation and changes by -180 ° due to propagation, and thus is 0 ° on the waveguide 4c. Similarly, S excited by the waveguide 4b and propagated to the waveguide 4c
The phase of the AW 10b is 90 [deg.] When excited and changes -90 [deg.] Due to propagation, so it is 0 [deg.] On the waveguide 4c. That is, in FIG. 1, each of the waveguides 4a, 4b, 4
SAW that is excited by c and propagates in the output IDT 5 direction
Are all in phase, and SAWs propagating in opposite directions are in opposite phase and cancel each other out. As a result, the waveguides 4a, 4
Most of the SAW excited by b and 4c propagates in the direction of the output IDT 5, so that the conventional S of this type is used.
It is twice as efficient as the AW correlation processor. Further, in the opposite direction of the output IDT 5, another output IDT
Since it is not necessary to dispose five, the chip size can be made small, and a plurality of output I's arranged apart from each other can be used.
There is no need to connect DT5.

Example 2. Second Embodiment FIG. 2 is a plan view showing a SAW correlation processing device according to a second embodiment of the present invention. In the embodiment shown in FIG. 2, the interval p between the adjacent waveguides 4a, 4b, 4c is set to p to (1/6 + n) · λ with respect to the integer n. Further, the phase of the SAW excited by the waveguide 4a is 120 °, the phase of the SAW excited by the waveguide 4b is 60 °, and the phase of the SAW excited by the waveguide 4c is 0 °. It is set. As means for this, the input IDTs 2a, 2b, 2c and the waveguides 4a, 4b,
The input IDTs 3 that are adjacent to each other and have a constant distance from 4c
The distances a, 3b, 3c and the waveguides 4a, 4b, 4c are set to 60 °. As a result,
In the example shown in, the SAWs 8a and 9a incident on the waveguide 4a are
Of the SAWs 8b and 9b incident on the waveguide 4b are 0 ° and 60 °, respectively.
And the phases of the SAWs 8c and 9c incident on the waveguide 4c can both be set to 0 °.
The phase of the SAW excited at c is set to the required value.

The output IDT 5 is excited by the waveguide 4b.
The phase of the SAW 10a propagating in the opposite direction is the sum of the phase 60 ° when excited in the waveguide 4b and the phase change amount -60 ° when propagating to the waveguide 4a, which is 0 °. .. Similarly, the phase of the SAW 10d excited by the waveguide 4c and propagating to the waveguide 4a is −120 °, and the phase of the SAW excited by the waveguide 4a on the waveguide 4a is 120 °. .. Therefore, these SAW
Since the sum of the two is the sum of the amplitudes of the components whose phases are 0 °, −120 °, and 120 °, it becomes almost zero, and the output IDT5
Few SAWs propagate in the opposite direction. On the other hand, all the SAWs 10b and 10c propagating in the direction of the output IDT 5 are 0 ° on the waveguide 4c, and all propagate in phase. Therefore, almost all the power of the SAW excited by the waveguides 4a, 4b, 4c propagates in the direction of the output IDT 5, and the power of the SAW is less than that of the conventional SAW correlation processor of this type.
Double efficiency is high.

Example 3. Third Embodiment FIG. 3 is a plan view showing a SAW correlation processing device according to a third embodiment of the present invention. In the embodiment shown in FIG. 3, the interval p between the adjacent waveguides 4a, 4b, 4c is set to p to (1/3 + n) · λ with respect to the integer n. Furthermore, the phase of the SAW excited by the waveguide 4a is 240 °, the phase of the SAW excited by the waveguide 4b is 120 °, and the phase of the SAW excited by the waveguide 4c is 0 °.
It is set to be ゜. Each waveguide 4a, 4b, 4
In the example shown in FIG. 3, adjacent input IDTs 2a, 2b, 2c are used as means for setting the phase at c to a required value.
And the waveguides 4a, 4b, 4c are separated by 60 °, and the adjacent input IDTs 3a, 3b, 3c and the waveguides 4a, 4b, 4c are separated by 60 °. SAW 8a incident on the waveguides 4a, 4b, 4c,
The phases of 8b, 8c, 9a, 9b, and 9c are set to SA
W8a, 9a is 120 °, SAW8b, 9b is 60 °,
The SAWs 8c and 9c are set to be 0 °. Even in this case, the effect is clear if it is seen how the phase of the SAW excited in each of the waveguides 4a, 4b, 4c changes by propagating to the other waveguides 4a, 4b, 4c. .. That is, SAWs 10a and 10d excited by the waveguides 4b and 4c and SAs excited by the waveguide 4a.
The phases of W in the waveguide 4a are 0 ° and −2, respectively.
Since they are 40 ° and 240 °, the sum of them becomes almost zero, and there is almost no SAW propagating to the side opposite to the output IDT 5. On the other hand, S excited by the waveguides 4a and 4b
SAW excited by AWs 10c and 10b and waveguide 4c
All the phases in the waveguide 4c are 0 ° and are in phase. Therefore, the SA excited by the waveguides 4a, 4b, 4c
Most of the electric power of W propagates in the direction of the output IDT 5.

Example 4. In the SAW correlation processing device according to the present invention shown in FIGS. 1, 2 and 3, the waveguides 4a, 4b,
The propagation direction of the SAW excited by 4c is the input ID
The case where the SAWs 8a, 8b, 8c, 9a, 9b, and 9c excited by the T2a, 2b, 2c, 3a, 3b, and 3c are perpendicular to the propagation directions is shown. The propagation direction of the SAW excited by the input IDTs 2a, 2b, 2c, 3a, 3b,
SAW 8a, 8b, 8c, 9a excited by 3c,
It is not always perpendicular to the propagation directions of 9b and 9c. Figure 4
In the SAW correlation processing apparatus of the fourth embodiment according to the present invention shown in FIG. 1, the input IDTs 2a, 2b, 2c, 3a, 3b,
The waveguides 4a, 4b, 4c are arranged along the propagation direction of the SAW excited by 3c, and the output IDT 5 is arranged.
Is set so that the waveguides 4a, 4a
SAW excited by b and 4c can be efficiently output I
It can be received by DT5. In addition, S shown in FIG.
In the AW correlation processing device, the input IDTs 2a, 2b, 2
c, 3a, 3b, 3c, the structure of the output IDT 5, the phase of the SAW excited by the waveguides 4a, 4b, 4c, and the propagation of the SAW excited by the waveguides 4a, 4b, 4c. The waveguides 4a, 4 along the direction
The distance between b and 4c is the same as that shown in FIG. 1, FIG. 2, or FIG.

Example 5. In the SAW correlation processing device according to the present invention shown in FIGS. 1, 2, 3, and 4, the input IDT 2
a, 2b, 2c, 3a, 3b, 3c, and output I
Although the configuration of the DT 5 is shown to include one IDT, the SAW correlation processing device according to the present invention uses the input IDTs 2a, 2b, 2c, 3a, 3b, 3 and 3.
The c and the output IDT 5 may have any function as long as they have a function of converting an electric signal into a SAW and an ID of any format.
Even if T is used, the effect is the same. In the SAW correlation processing apparatus according to the fifth embodiment of the present invention shown in FIG.
A plurality of output IDTs 5a and 5b are arranged in the DT5,
By connecting the output IDTs 5a and 5b through the phase shifter 11, a unidirectional IDT is formed, and the waveguide 4 is formed.
A SA having a higher efficiency can be obtained by configuring so that the SAW excited by a, 4b, and 4c can be received more efficiently.
There is an effect of obtaining the W correlation processing device.

Example 6. In the embodiment of the SAW correlation processing apparatus according to the present invention shown in FIGS. 1, 2, 3, 4, and 5, the input IDTs 2a, 2b, 2c, 3a, 3b, and 3c are divided into waveguides 4a, 4b, and Although the distance from 4c is changed, in the SAW correlation processing apparatus according to the sixth embodiment of the present invention shown in FIG. 6, the input IDTs 2 and 3 have a structure that changes the phase of the SAW incident on the waveguide 4. It is sufficient if the positive electrode 6 and the negative electrode 7 of the input IDT 2 are bent and the positive electrode 6 and the negative electrode 7 are bent without changing the distance between the positive electrode 6 and the negative electrode 7. The same effect can be obtained even if the distance between the crossing point and the waveguide 4 is changed.

Example 7. In the SAW correlation processing device according to the present invention shown in FIGS. 1, 2, 3, 4, 5, and 6, in order to set the phase of the SAW excited by each waveguide 4 to a required value, the input IDTs 2 and 3 are set. Divide each input IDT2,
3 and each of the waveguides 4 are changed, or the input IDTs 2 and 3 are bent without changing the distance between the positive electrode 6 and the negative electrode 7. The SAW correlation processing apparatus according to the present invention is not limited to this, and the conductor 12 is provided between the input IDTs 2 and 3 and each waveguide 4 as in the SAW correlation processing apparatus according to the seventh embodiment of the present invention shown in FIG. The effect is the same even if arranged. Ie conductor 1
Utilizing the fact that the SAW propagation velocity is different between the region where 2 is present and the region where 2 is absent, and the fact that there is a phase difference between the SAW propagated through the conductor 12 and the SAW propagated where there is no conductor 12 is utilized. However, the effect is the same.

Example 8. In the SAW correlation processing device according to the present invention shown in FIGS. 1, 2, 3, 4, 5, and 6, in order to set the phase of the SAW excited by each waveguide 4 to a required value, the input IDTs 2 and 3 are set. Divide each input IDT2,
3 and each of the waveguides 4 are changed, or the input IDTs 2 and 3 are bent without changing the distance between the positive electrode 6 and the negative electrode 7, or the input IDT 2 is used.
Although the conductor 12 is arranged between the second and third waveguides 4 and each of the waveguides 4, the S according to the eighth embodiment of the present invention shown in FIG.
In the AW correlation processing device, the phase of SAW excited in each of the waveguides 4 is set to a required value by changing the length L of each of the waveguides 4. This is because the phase of the SAW excited in the waveguide 4 also depends on the length L of the waveguide, as is clear from Equation 1. Therefore,
By changing the length L of the waveguide 4, it is possible to change the phase of the SAW excited in the waveguide 4, and the present invention has the same effect even in this case.

Example 9. 1, 2, 3, 4, 5, 6,
In the SAW correlation processing device according to the present invention shown in FIGS. 7 and 8, in order to set the phase of the SAW excited in the waveguide 4 to a required value, the distance between the input IDTs 2 and 3 and each of the waveguides 4 is set. Or a structure in which the positive electrode 6 and the negative electrode 7 are bent, or the input IDTs 2 and 3
A conductor 12 between the waveguide 4 and the waveguide 4, or
Although the length L of each waveguide 4 is changed, in the SAW correlation processing device according to the ninth embodiment of the present invention shown in FIG.
As a method of changing the phase of the SAW incident on each waveguide 4, the phase shifter 11 is added to the divided input IDTs 2 for input.
The same effect can be obtained by inputting an electric signal via.

In the above description, the number of waveguides 4 is three.
Although one or four cases have been described, the present invention is not limited to this, and the number of waveguides 4 may be arbitrary as long as it is plural. Furthermore, the waveguides 4 need not all have the same shape. In addition, a plurality of input IDTs 2a, 2b, 2c, 3
Input IDTs 2a, 2 when divided into a, 3b, and 3c
The electrical connection method between b and 2c and between the input IDTs 3a, 3b, and 3c need not be electrically parallel connection as shown in FIGS. 1, 2, 3, 4, 5, and 9. As long as the phase of the SAW incident on the waveguide 4 is a required value, the effect is the same in any case such as series connection or combination of parallel connection and series connection. In the above embodiment, the input IDTs 2 and 3 and the output IDT 5 are also included.
Shows a case where the positive electrode 6 and the negative electrode 7 intersect one by one, but the present invention is not limited to this, and the positive electrode 6 and the negative electrode 7 intersect two by two. In the case of, or in the case of a structure in which there is a floating electrode that is not connected to an electric terminal between the positive electrode 6 and the negative electrode 7,
All IDTs having a conversion function with W can be applied.

The surface acoustic wave (SAW) in the surface acoustic wave correlation processing apparatus according to the present invention is a surface acoustic wave that propagates with energy concentrated on the surface of the substrate, the thin film surface, or the boundary between different media. They are shown generically, and SH waves, Stoneley waves, bulk waves, etc. are also shown in addition to Rayleigh waves. Further, the correlation processing in the surface acoustic wave correlation processing apparatus according to the present invention is generally applicable to both mathematically treated as convolution (convolution integral) and correlation (correlation). The time axes of the input signal and the reference signal input to the surface wave correlation processing device may be set appropriately.
Further, the effect is the same whether the piezoelectric body is composed of a single piezoelectric crystal or a piezoelectric thin film formed on a substrate such as a semiconductor or glass. Of course, when the piezoelectric thin film is formed on the substrate, the same effect can be obtained even if another dielectric or conductor thin film is inserted on the surface of the piezoelectric thin film or between the piezoelectric thin films.

Further, in the above embodiment, the distance p between the adjacent waveguides 4 is p to (1/2 + n) · λ, (1 /) with respect to the wavelength λ of the SAW excited in the waveguide 4. 6 + n)
Although three cases of λ and (1/3 + n) · λ have been shown, the present invention is not limited to this, and the phase of the SAW propagating in the direction of the output IDT 5 is in-phase or close to in-phase, and SAW propagating in the opposite direction to the output IDT 5
It suffices that the phases of are canceled out as a whole.

[0033]

As described above, according to the present invention, it is possible to obtain the surface acoustic wave correlation processing apparatus having high efficiency without increasing the chip size.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of the present invention.

FIG. 2 is a plan view showing a second embodiment of the present invention.

FIG. 3 is a plan view showing a third embodiment of the present invention.

FIG. 4 is a plan view showing Embodiment 4 of the present invention.

FIG. 5 is a plan view showing a fifth embodiment of the present invention.

FIG. 6 is a plan view showing Embodiment 6 of the present invention.

FIG. 7 is a plan view showing Embodiment 7 of the present invention.

FIG. 8 is a plan view showing an eighth embodiment of the present invention.

FIG. 9 is a plan view showing Embodiment 9 of the present invention.

FIG. 10 is a plan view showing a conventional surface acoustic wave convolver.

FIG. 11 is a plan view showing a conventional surface acoustic wave convolver.

FIG. 12 is a plan view showing a conventional surface acoustic wave convolver.

[Explanation of symbols]

 1 piezoelectric body 2 interdigital transducer for input 3 interdigital transducer for input 4 waveguide 5 interdigital transducer for output 6 positive electrode of interdigital transducer 7 negative electrode of interdigital transducer 8 excited surface acoustic wave 9 excited Surface acoustic wave 10 Excited surface acoustic wave 11 Phase shifter 12 Conductor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuzo Waka, 1-1 1-1 Ofuna, Kamakura-shi Electronic Systems Research Center, Mitsubishi Electric Corporation

Claims (1)

[Claims] 1. At least a pair of a first electrode and a second electrode formed on a piezoelectric body and converting the first electric signal and the second electric signal into surface acoustic waves, respectively, and the first electrode. The first surface acoustic wave and the second surface acoustic wave respectively excited from the second electrode are propagated in opposite directions, and the first surface acoustic wave and the second surface acoustic wave are mixed to generate a third surface acoustic wave. A plurality of waveguides having nonlinearity for exciting surface acoustic waves, and a third electrode provided on one side of the waveguides for converting a third surface acoustic wave excited in the waveguides into an electric signal. And an arrangement interval of the plurality of waveguides and a surface acoustic wave excitation phase, the surface acoustic waves excited in each of the plurality of waveguides and propagating in the direction of the third electrode are combined in the same phase. , An elastic table propagating in the opposite direction to the third electrode A surface acoustic wave correlation processing device, characterized in that a surface wave is set to a predetermined value that is synthesized with phases that cancel each other out.