JPH0936698A - Surface acoustic wave device, and receiving device and communication system using the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a convolution output signal by forming a projection part as part of a printed substrate on its surface where a package system is mounted so that an input lead pin and an output lead pin are partitioned. SOLUTION: The part consisting of a piezoelectric substrate 1, and comb-like input electrodes 2 and 3 and an output electrode formed on the surface of the piezoelectric substrate 1 is a surface acoustic wave convolver, and used while mounted on the package system 9. On the surface of the printed board 14 where the package system 9 is mounted, the projection part 19 is formed across input lead pins 7a and 7b and an output lead pin 8 by projecting part of the printed board 14, and this projection part 19 is arranged in contact with the bottom surface of the package system 9. This constitution reduces the noise floor of an output waveform and it is made easy to detect the convolution output signal.

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 device, a receiving device and a communication system using the same, and more particularly, a surface acoustic wave device having an input part and an output part structurally separated from each other, and the surface acoustic wave device. The present invention relates to a receiving device and a communication system that prevent noise components from being mixed by using a surface wave device and establish synchronization at high speed.

[0002]

2. Description of the Related Art A surface acoustic wave is a surface acoustic wave propagating along a surface or boundary surface of a propagation medium, and most of its energy is contained within about one wavelength from the surface, so that a relatively small input power can be easily obtained. High-density elastic energy can be obtained, the non-linear effect becomes larger than that of the bulk wave, and its application as a communication device is expected.

As the nonlinear effect of this surface acoustic wave, harmonic generation, parametric mixing effect, parametric oscillation, direct current effect, convolution (Convolutio)
n) Effects and others are known, especially using surface acoustic waves
A surface acoustic wave device using a surface acoustic wave convolver for extracting convolution outputs of two input signals has recently been applied to signal processing devices such as spread spectrum communication system (Spread Spectrum Communication) using a high frequency signal and a wide band frequency. Its importance is increasing,
Actively studied.

7 and 8 are schematic views showing such a conventional surface acoustic wave device. In the figure, 1 is a piezoelectric substrate, 2 and 3
Is a comb-shaped input electrode formed on the surface of the piezoelectric substrate 1, 4 is an output electrode formed on the surface of the piezoelectric substrate 1, 5a and 5b are input bonding wires, 6 is an output bonding wire, and 7a and 7b are input Lead pin, 8 output lead pin, 9 package stem, 10 sealing cap,
Reference numerals 11a and 11b are input side external circuit sections including a matching circuit, a filter, an amplifier, and the like, and 12 is a matching circuit, a filter,
Output side external circuit section composed of an amplifier and the like, 13a, 13
Reference numeral b is a lead pin soldering land pattern, 14 is a printed circuit board, 15a and 15b are input terminals, and 16 is an output terminal. The above is treated as a surface acoustic wave device.

In the figure, the portion constituted by the piezoelectric substrate 1, the comb-shaped input electrodes 2, 3, and the output electrode 4 is a surface acoustic wave convolver, which is mounted on the package stem 9 for use. The comb-shaped input electrodes 2 and 3 and the output electrode 4 of the surface acoustic wave convolver are made of a conductive material such as aluminum, and are usually formed directly on the surface of the piezoelectric substrate 1 using a photolithography technique.

Although the package stem 9 is actually used in a hermetically sealed state by the sealing cap 10, it is omitted in FIG.

The package stem 9 enclosing the surface acoustic wave convolver is mounted on a printed circuit board 14 together with the input side external circuit portions 11a and 11b and the output side external circuit portion 12, and is used. To facilitate understanding, the package stem 9 is attached to the printed circuit board 14
It is shown in a more floating state.

FIG. 8 is a schematic view of the package stem 9 sealed by the sealing cap 10 mounted on the printed board 14 as seen from the direction of the arrow in FIG.

In the surface acoustic wave device having such a structure, when an electric signal of carrier frequency ω is input to the input terminal 15a, the signal is passed through the input side external circuit 11a, the input lead pin 7a, and the input bonding wire 5b. After reaching the comb-shaped input electrode 3, the surface acoustic wave is excited on the comb-shaped input electrode 3 by the piezoelectric effect of the substrate. Similarly, when an electric signal of carrier frequency ω is input to the input terminal 15b, the signal is input to the input side external circuit 11b, the input lead pin 7b,
The comb-shaped input electrode 2 via the input bonding wire 5a
And the surface acoustic wave is excited on the comb-shaped input electrode 2 by the piezoelectric effect of the substrate.

The two surface acoustic waves propagate in opposite directions on the piezoelectric substrate 1 while being confined in the output electrode by the output electrode 4 acting as a waveguide.

When these two surface acoustic waves overlap on the output electrode 4, the convolution of these two surface acoustic waves (frequency 2) is caused by the physical nonlinear effect of the piezoelectric substrate 1.
ω) signal is generated. To explain this effect in more detail,
Surface acoustic wave (angular frequency ω, wave number k) from the comb-shaped input electrode 2
, And the surface acoustic wave (angular frequency ω,
Wave number-k) is excited and superposed under a flat plate-shaped electrode provided in the center. If the energy of the surface acoustic wave is more than a predetermined value, it will be 2 depending on the elastic / piezoelectric non-linear characteristic of the piezoelectric substrate as the propagation medium. The product of two surface acoustic waves is performed, and a non-linear term of two sets of components, that is, a frequency (2ω, 0) and a frequency 0 (0, 2k) is generated at the output electrode 4 which is the central electrode. Since the wave number of the component having the frequency of 2ω is 0, that is, the wavelength is infinite, it can be extracted as an electric signal by the flat plate output electrode 4 at the center.

The convolution signal (2ω) thus generated is taken out as an electric signal from the output terminal 16 via the output electrode 4, the output bonding wire 6 and the output lead pin 8, and the output side external circuit 12.

Such a so-called convolver convolution mechanism is described in, for example, "Shibayama," Application of surface acoustic waves ", Television, 30.457 (197).
6) ”and the like.

[0014]

However, the signal level of the convolution output that can be taken out as an electric signal is extremely low, which is about 10 ^-5 to 10 ^-6 of the input signal level. Therefore, in the above-mentioned conventional example, it is shown in FIG. As described above, part of the input signal is radiated into the air from the input lead pins 7a and 7b, and a small gap 17 narrowed between the package stem 9 and the printed circuit board 14 is shown in FIG.
And then reaches the output lead pin 8 (hereinafter referred to as a direct signal), the input signal is mixed into the output signal component, the noise floor of the convolution output waveform increases, and the convolution output There is a problem that it becomes difficult to detect a signal.

Further, the direct signal component also includes a component having the same carrier frequency (2ω) as the convolution output component, and this causes a time variation in the convolution output waveform. Difficult to detect.

There were some problems such as

[0017]

SUMMARY OF THE INVENTION An object of the present invention is to provide a surface acoustic wave device which can easily detect a convolution output signal by suppressing a part of an input signal from being mixed in an output signal component. Especially.

The present invention has been made to achieve the above object, and a surface acoustic wave element having input / output electrodes for transmitting and receiving surface acoustic waves formed on the main surface of a piezoelectric substrate, and the above elastic surface. It has a package stem in which a surface acoustic wave element is encapsulated, which has an input lead pin for extracting an input signal and an output lead pin for extracting an output signal, and a printed circuit board for mounting the package stem. In the surface acoustic wave device, a part of the printed board is convex so as to partition the input lead pin and the output lead pin on the surface of the printed board on which the package stem of the conductive material is mounted. It is characterized in that it is formed so as to project.

[0019]

According to the above structure of the present invention, the direct signal that propagates through the slight gap between the package stem and the printed circuit board and reaches the output lead pin can be suppressed by the conductive substance. Therefore, the noise floor of the convolution output waveform is reduced, and the convolution output signal can be easily detected.

[0020]

Embodiments of the present invention will be described below.

[First Embodiment] FIGS. 1 and 2 are schematic views showing a first embodiment of a surface acoustic wave device according to the present invention.
In the figure, 1 is, for example, a piezoelectric substrate of lithium niobate, 2, 3
Is a comb-shaped input electrode formed of a metal such as aluminum on the surface of the piezoelectric substrate 1, 4 is an output electrode formed of a metal such as aluminum on the surface of the piezoelectric substrate 1, and 5a and 5b are Al and A
An input bonding wire made of u, Cu, tin or an alloy of each, 6 is an output bonding wire, 7
a and 7b are input lead pins of ribbon type, gull wing lead type, etc., 8 are output lead pins of the same type, 9
Is a package stem made of a conductive material, 10 is a metal sealing cap for preventing the entry of weak radio waves, 11a and 11b are matching circuits for sequentially matching from the input lead pins 7a and 7b side, and a predetermined band is filtered. Input-side external circuit unit including a filter and an amplifier that amplifies with a predetermined gain, 1
Reference numeral 2 is an output side external circuit portion similarly composed of a matching circuit, a filter, an amplifier, and the like, 13a and 13b are lead pin soldering land patterns for soldering lead pins, and 14 is at least the side on which the package stem 9 is mounted. A printed circuit board having a copper foil, 15a and 15b are input terminals for inputting, for example, spread code signals, 16 is an output terminal for outputting a convolution signal, and 19 is a conductor and is formed on the printed circuit board 14. It is a convex protrusion.

In the figure, the portion formed by the piezoelectric substrate 1, the comb-shaped input electrodes 2, 3, and the output electrode 4 is a surface acoustic wave convolver, which is mounted on the package stem 9 for use. The comb-shaped input electrodes 2 and 3 and the output electrode 4 of the surface acoustic wave convolver are made of a conductive material such as aluminum, and are usually formed directly on the surface of the piezoelectric substrate 1 using a photolithography technique.

Although the package stem 9 is actually used in a hermetically sealed state by the sealing cap 10, it is omitted in FIG.

The package stem 9 enclosing the surface acoustic wave convolver is mounted and used on the printed circuit board 14 together with the input side external circuit portions 11a and 11b and the output side external circuit portion 12, but in FIG. In order to make it easier to understand
It is described in a state of being floated from 4.

FIG. 2 is a schematic view of the package stem 9 sealed by the sealing cap 10 mounted on the printed board 14 as seen from the direction of the arrow in FIG.

In this embodiment, as shown in FIGS. 1 and 2, the input lead pins 7a and 7b and the output lead pin 8 are arranged so as to cross the surface of the printed board 14 on which the package stem 9 is mounted. A convex projecting portion 19 is formed by projecting a part of the printed board 14 in a convex shape, and the convex projecting portion 19 is arranged and formed so as to contact the bottom surface of the package stem 9.

In the surface acoustic wave device having such a structure, when an electric signal of carrier frequency ω is input to the input terminal 15a, the signal is passed through the input side external circuit portion 11a, the input lead pin 7a, and the input bonding wire 5b. Reach the comb-shaped input electrode 3, and the surface acoustic wave is excited on the comb-shaped input electrode 3 by the piezoelectric effect of the substrate. Similarly, when an electric signal of carrier frequency ω is input to the input terminal 15b, the signal is input to the input side external circuit portion 11b and the input lead pin 7.
b, reaches the comb-shaped input electrode 2 via the input bonding wire 5a, and the surface acoustic wave is excited on the comb-shaped input electrode 2 by the piezoelectric effect of the substrate.

The two surface acoustic waves propagate in the opposite directions on the piezoelectric substrate 1 while being confined in the output electrode by the output electrode 4 acting as a waveguide.

When the two surface acoustic waves overlap each other on the output electrode 4, the convolution of the two surface acoustic waves (frequency 2) is caused by the physical nonlinear effect of the piezoelectric substrate 1.
ω) signal is generated. The convolution signal generated in this way is applied to the output electrode 4 and the output bonding wire 6
The output lead pin 8 and the output side external circuit section 12 output the output terminal 16 as an electric signal having a frequency 2ω component.

Here, some of the direct signal components generated at the input lead pins 7a and 7b are directed toward the output lead pin 8 through a slight gap 17 sandwiched between the package stem 9 and the printed circuit board 14 in FIG. It propagates like A shown,
In the gap 17, as shown in FIGS. 1 and 2, a part of the printed circuit board is formed in a convex shape so as to cross the input lead pins 7a, 7b and the output lead pin 8, and the convex projection 19 of the package stem. Since it is in contact with the bottom surface, it is possible to suppress the direct achievement from reaching the output lead pin 8. As a result, mixing of the direct signal, which is a part of the input signal, into the output signal of the low output level is reduced, the noise floor of the convolution output waveform is reduced, and the detection of the convolution output signal is facilitated.

In particular, when the convolution output signal is used as a correlator for the surface acoustic wave device to establish synchronization in the spread spectrum communication system, the output power is extremely low with respect to the input power, so that the mixture of direct signals is suppressed. As a result, the noise component is suppressed, and therefore, the signal of the correlation peak having a good S / N can be obtained, so that the synchronization signal can be acquired quickly and stably, and the establishment of synchronization is ensured.

In the present embodiment, the surface mounting type is shown as the package stem 9, but a package stem other than this, for example, a package stem in which pins are inserted into a printed circuit board may be used.

In this embodiment, an example in which lithium niobate is used for the piezoelectric substrate 1 is shown, but other piezoelectric substrates such as quartz, lithium tantalate, piezoelectric ceramics and non-piezoelectric substrates are also used. Other piezoelectric substrates such as the formed piezoelectric film may be used.

Further, although the elastic convolver is used in this embodiment, another convolver such as an AE convolver may be used.

Further, in the present embodiment, the structure in which the convolution output is taken out from one place of the output electrode is shown, but the structure in which the convolution output is taken out from a plurality of places may be used.

Further, in the above-mentioned embodiment, an example is shown in which the printed circuit board 14 is provided with the convex projecting portion 19 which is projected in a convex shape. It may be formed in a rectangular shape, and the convex protruding member may be placed on the copper foil of the printed board 14 and soldered, and direct signals can be blocked. In addition, even if the convex protrusion 19 is formed by forming a copper plate into a Π shape and soldering both ends to the copper foil of the printed circuit board 14, an inverted T-shape or an L-shape is obtained.
Even if a copper plate formed in a shape is soldered on the copper foil of the printed circuit board 14 at a height that makes contact with the package stem, it is possible to achieve the input / output isolation insulation almost equal to the above and prevent the arrival of direct waves. .

In the above embodiment, it is described that the direct signal is transmitted from the input lead pin 7 to the output lead pin 8. However, in reality, the direct signals cross each other, and the direct signal from the output lead pin 8 to the input lead pin 7 is transmitted. The signal level reaching directly to is extremely small compared to the input level, and is negligible. However, when the internal amplifier is mounted on the output end of the output electrode on the package stem 9, the mixing into the input signal cannot be ignored, so that the input / output separation effect according to the present embodiment is also exhibited in this case. .

[Second Embodiment] FIGS. 3 and 4 are schematic views showing a second embodiment of the surface acoustic wave device according to the present invention.
In this figure, the same members as those in FIGS. 1 and 2 are designated by the same reference numerals, and the duplicated description will be omitted. In the figure, the member 20 is a conductive rubber. This conductive rubber 2
0 is a general-purpose rubber such as natural rubber or polybutadiene rubber to which metal particles or carbon fine powder is added to make it conductive, and may be used for preventing static electricity, shielding electromagnetic waves, and the like.

In the present embodiment, as shown in FIGS. 3 and 4, the input lead pins 7a and 7b and the output lead pin 8 are arranged so as to cross the surface on which the package stem 9 of the printed circuit board 14 is mounted. A conductive rubber 20 is arranged, and the conductive rubber 20 is arranged and formed so as to contact the bottom surface of the package stem 9. In this case, the conductive rubber 20 may be pressure-bonded and fixed, or may be fixed on the printed circuit board 14 using a conductive adhesive.

In the surface acoustic wave device having such a structure, the direct signal component A propagating in the gap 17 toward the output lead pin 8 is output by the conductive rubber 20 as in the first embodiment. It is possible to suppress the arrival at the power lead pin 8, and as a result, the mixing of the input signal into the output signal component is reduced, the noise floor of the convolution output waveform is reduced, and the detection of the convolution output signal is facilitated.

Further, in this embodiment, on the surface of the printed board 14 on which the package stem 9 is mounted,
Since the conductive rubber 20 is provided so as to cross the input lead pins 7a and 7b and the output lead pin 8, it is not necessary to process the shape of the printed circuit board, and the production cost can be reduced accordingly.

In this embodiment, an example in which the conductive rubber is used for the member 20 is shown, but the material of the member 20 is not limited to this example, and for example, a metal plate or a conductive polymer such as polythiazyl or polyacetylene. Or a conductive material such as a conductive resin mold, a conductive film formed by molding a composite material containing metal, black smoke, or the like, or a metal thin film adhered thereto, or a non-conductive material coated with a conductive film may be used. .

Further, in this embodiment, the surface mounting type is shown as the package stem 9, but a package stem other than this, for example, a type in which pins are inserted into a printed board may be used.

In this embodiment, an example in which lithium niobate is used for the piezoelectric substrate 1 is shown, but other piezoelectric substrates such as quartz, lithium tantalate, piezoelectric ceramics and non-piezoelectric substrates are used. Other piezoelectric substrates such as the formed piezoelectric film may be used.

In this embodiment, the elastic convolver is used, but another convolver such as an AE convolver may be used.

Further, in the present embodiment, the structure in which the convolution output is taken out from one place of the output electrode is shown, but the structure in which the outputs are taken out from a plurality of places may be used.

[Third Embodiment] FIGS. 5 and 6 are schematic views showing a third embodiment of the surface acoustic wave device according to the present invention.
In this figure, the same members as those in FIGS. 1 and 2 are designated by the same reference numerals, and the duplicated description will be omitted. The member 21 is a solder for fixing the input / output lead pin on the side surface of the printed board 14 opposite to the package stem 9.

In the present embodiment, as shown in FIGS. 5 and 6, on the surface of the printed circuit board 14 on which the package stem 9 is mounted, the input lead pins 7a and 7b and the output lead pin 8 are electrically conductive so as to surround them. The rubbers 20 are formed, and the conductive rubbers 20 are arranged and formed so as to contact the bottom surface of the package stem 9.

Also in the surface acoustic wave device having such a structure, as in the first embodiment, the direct signal component A propagating in the gap 17 toward the output lead pin 8 is shielded by the conductive rubber 20. As an effect, the arrival at the output lead pin 8 can be suppressed, and as a result, the mixing of the input signal into the output signal component is reduced, the noise floor of the convolution output waveform is reduced, and the convolution output signal can be easily detected. become.

Further, in this embodiment, the conductive rubber 2
Since 0 is formed so as to surround the input lead pins 7a and 7b and the output lead pin 8, respectively, the arrival of the direct signal A to the output lead pin 8 can be suppressed and, in addition, from the outside. The arrival of the unnecessary signal B can also be suppressed, the noise floor of the convolution output waveform is reduced accordingly, and the detection of the convolution output signal is facilitated.

In this embodiment, an example in which the conductive rubber is used for the member 20 is shown, but the material of the member 20 is not limited to this example, and as described in the second embodiment, for example, a metal plate is used. Or a conductive material such as a conductive resin mold, a conductive film, or a non-conductive material coated with a conductive film, or the printed board may be processed into a shape as shown in this embodiment. .

Further, in this embodiment, the member 20 is shown in FIG.
Although the example is shown in which the shape pattern is formed as shown in FIG. 5, the shape of the member 20 is not limited to this example, and the input lead pin 7a,
It may have a tubular shape so as to surround 7b and the output lead pin 8.

In the present embodiment, the package stem 9 is of the type in which the input / output lead pins are inserted into the printed circuit board 14, but a package stem other than this, for example, a surface mount type package stem, may be used. Good. The printed circuit board shown in FIG. 5 is a double-sided board, and the matching circuit, the filter, and the amplifier on the input side and the output side are mounted on the side opposite to the surface acoustic wave element.

Further, in this embodiment, an example in which lithium niobate is used for the piezoelectric substrate 1 is shown, but other piezoelectric substrates such as quartz, lithium tantalate, piezoelectric ceramics, non-piezoelectric substrates are used. Other piezoelectric substrates such as the piezoelectric film formed on the above may be used.

In this embodiment, the elastic convolver is used, but another convolver such as an AE convolver may be used.

Further, in the present embodiment, the structure in which the convolution output is taken out from one place of the output electrode is shown, but the structure in which the convolution output is taken out from a plurality of places may be used.

The SAW convolver has been described as the surface acoustic wave device in the first to third embodiments, but regarding the electrical and physical separation of the input and output signals, a bandpass filter or a matched filter using the surface acoustic wave is used. A filter or the like may also have the same problem, so that the same effect can be obtained even if the present invention is applied to these surface acoustic wave elements. In particular, since the used frequency is a high frequency signal of microwave or millimeter wave, the presence of the convex protrusion is extremely effective.

[Fourth Embodiment] FIG. 9 is a block diagram showing an example of a communication system using the surface acoustic wave device as described above. In the figure, reference numeral 40 denotes a transmitting device. The transmitter 40 spread-spectrum modulates a signal to be transmitted using a spread code and transmits the signal from an antenna 401. The transmitted signal is received by the receiving device 41 and demodulated. The receiving device 41 includes an antenna 411, a high frequency signal processing unit 412, a synchronizing circuit 413, a code generator 414,
It comprises a spread demodulation circuit 415 and a demodulation circuit 416.
The reception signal received by the antenna 411 is filtered and amplified within a predetermined band by the high frequency signal processing unit 412, and is output as it is as a transmission frequency band signal or as an appropriate intermediate frequency band signal. The signal is input to the synchronizing circuit 413.

The synchronizing circuit 413 includes the surface acoustic wave device 4131 shown in the first to third embodiments of the present invention,
The modulation circuit 4132 that modulates the reference spreading code input from the code generator 414 and the signal output from the surface acoustic wave device 4131 are processed, and the spreading code signal and the clock synchronization signal for the transmission signal are processed by the code generator 414. It comprises a signal processing circuit 4133 for outputting. Surface acoustic wave device 41
An output signal from the high frequency signal processing unit 412 and an output signal from the modulation circuit 4132 are input to 31 and a convolution operation of two input signals is performed. Here, assuming that the reference spreading code input from the code generator 414 to the modulation circuit 4132 is a code obtained by time-reversing the spreading code transmitted from the transmitting side, in the surface acoustic wave device 4131 using the surface acoustic wave convolver element. A correlation peak is output when the synchronization-specific spreading code component and the reference spreading code included in the received signal match on the waveguide of the output electrode of the surface acoustic wave device 4131. At this time, since two input signals and one output convolution signal are separated and transmission of the direct signal can be blocked, a large level difference can be achieved between the case where the correlation is obtained and the case where the correlation is not obtained. The signal processing in the latter stage can be processed accurately without any error.

Next, the signal processing circuit 4133 detects the correlation peak from the signal input from the surface acoustic wave device 4131, and shifts the code synchronization from the time from the code start of the reference spreading code to the correlation peak output. The amount is calculated, and the code synchronization signal and the clock signal are output to the code generator 414. At this time, the high frequency signal processing unit 4 is configured by the negative feedback loop including the surface acoustic wave device 4131, the signal processing circuit 4133, the code generator 414 and the modulation circuit 4132.
Since the spread code component for synchronization from 12 and the noise floor are drastically reduced and the level of the convolution output signal is high, a stable synchronization loop can be established at high speed and synchronization can be ensured reliably.

After the synchronization is established, the code generator 414 generates a spreading code in which the clock and the spreading code phase match with the spreading code on the transmitting side. This spreading code is a spreading demodulation circuit 41.
5, the signal is multiplied by the synchronization-dedicated spreading code component from the high-frequency signal processing unit 412, and the signal before spread modulation is restored. The signal output from the spread modulation / demodulation circuit 415 is a so-called amplitude modulation (ASK: Amplitude Shift Keyi).
ng), frequency modulation (FSK: Frequency Shift Keyin)
g) Since the signal is modulated by a modulation method such as phase modulation (PSK: Phase Shift Keying), data demodulation is performed by the corresponding demodulation circuit 416 using, for example, a synchronous detection circuit or an envelope detection circuit.

In the SAW convolver used in this configuration, the output to the signal processing circuit 4133 is spatial with respect to the synchronization dedicated spread code component from the high frequency signal processing unit 412 and the reference spread code component from the code generator 414. Since it is separated from each other, the leakage of each spreading code and the direct signal of the spatial transmission can be suppressed, so that the convolution signal (2ω) is not mixed with the spreading signal component (ω) and the synchronization establishment is achieved at high speed. Also, the reliability of the synchronization tracking becomes high.

[Fifth Embodiment] FIGS. 10 and 11 are block diagrams showing an example of a transmitter and a receiver of a communication system using the surface acoustic wave device as described above. In FIG. 10 showing a block diagram of a transmission device, 501 is a serial-parallel converter that converts serially input data into n pieces of parallel data, and 502-1 to n are parallelized data and spread code generator. , A spreading code generator for generating n spreading codes PN1 to PNn and a spreading code PN0 dedicated to synchronization, and 504 a spreading code generator. Sync-only spreading code PN0 output from 503 and multiplier groups 502-1 to 502-1
An adder for adding n outputs of n, 505 is an adder 50
A high frequency stage for converting the output of 4 into a transmission frequency signal,
Reference numeral 506 is a transmission antenna.

FIG. 11 is a block diagram of the receiving apparatus.
In the figure, 601 is a receiving antenna, 602 is a high frequency signal processing unit, 603 is a synchronizing circuit for capturing and maintaining synchronization with the spreading code and clock on the transmitting side, and 604 is a synchronizing circuit 60.
A spreading code generator for generating n + 1 spreading codes and a reference spreading code, which are the same as the spreading code group on the transmission side, according to the code synchronization signal and the clock signal input from the reference numeral 3, and 605 is output from the spreading code generator 604. A carrier reproducing circuit for reproducing a carrier signal from the carrier reproducing spread code PN0 and the output of the high frequency signal processing unit 602, and 606 is an output of the carrier reproducing circuit 605, an output of the high frequency signal processing unit 602 and an output of the spread code generator 604. Some n spreading codes P
A baseband demodulation circuit that demodulates the baseband using N1 to PNn, and a parallel-serial converter 607 that parallel-serial converts n parallel demodulated data output from the baseband demodulation circuit 606.

In the above structure, on the transmission side, the input data is first converted into n parallel data equal to the number of code division multiplexes by the serial-parallel converter 501. On the other hand, the spreading code generator 503 generates n + 1 pieces of spreading codes PN0 to PNn having the same code period but different from each other. Of these, PN0 is dedicated to synchronization and carrier reproduction, is not modulated by the parallel data, and is directly input to the adder 504. The remaining n spreading codes PN1 to PNn are multiplied and modulated by n pieces of parallel data in the multiplier groups 502-1 to 50n to spread the occupied frequency bands and adder 504.
Is input to The adder 504 linearly adds the input n + 1 signals and outputs the added baseband signal to the high frequency stage 505. Subsequently, the baseband signal is converted into a high-frequency signal having an appropriate center frequency in the high-frequency stage 505 and transmitted from the transmission antenna 506.

Next, on the receiving side, the signal received by the receiving antenna 601 is appropriately filtered and amplified by the high frequency signal processing section 602, and is output as it is as a transmission frequency band signal or as an appropriate intermediate frequency band signal. It The signal is input to the synchronization circuit 603. The synchronization circuit 603 processes the signals output from the surface acoustic wave device 6031 and the modulation circuit 6032 for modulating the reference spread code input from the code generator 604 and the surface acoustic wave device 6031 described in the embodiment of the present invention. , A signal processing circuit 6033 for outputting a spread code synchronization signal and a clock synchronization signal for the transmission signal to a spread code generator 604.

The surface acoustic wave device 6031 uses any one of the surface acoustic wave convolver elements shown in the above embodiments, and the output signal from the high frequency signal processing section 602 and the modulation circuit 603 are used.
The output signal from 2 is input, and the convolution operation of the two input signals is performed. Here, the code generator 604
Assuming that the reference spreading code input to the modulation circuit 6032 is a code obtained by time-reversing the synchronization-dedicated spreading code transmitted from the transmission side, the surface acoustic wave device 6031 has a synchronization-dedicated spreading code component included in the received signal. A correlation peak is output when the reference spread code matches on the waveguide of the surface acoustic wave device 6031. At this time, since the two input signals and the one output signal are separated and insulated, it is possible to prevent the direct signal from being mixed into the convolution signal,
The noise floor is reduced, and the capture and synchronization tracking of the synchronization signal in the signal processing in the subsequent stage becomes reliable.

Next, the signal processing circuit 6033 detects the correlation peak from the signal output from the surface acoustic wave device 6031, and shifts the code synchronization from the time from the code start of the reference spreading code to the correlation peak output. The amount is calculated, a code synchronization signal and a clock signal are generated from the output level according to the amount of deviation, and the generated signals are output to the spread code generator 604.

After the synchronization is established, the spread code generator 604 generates a spread code group in which the clock and the spread code phase match with the spread code group on the transmission side. Of these code groups, the spread code PN0 dedicated to synchronization is input to the carrier reproduction circuit 605. The carrier reproduction circuit 605 despreads the reception signal converted to the transmission frequency band or the intermediate frequency band which is the output of the high frequency signal processing unit 602 by the synchronization-dedicated spreading code PN0, and reproduces the carrier wave in the transmission frequency band or the intermediate frequency band. .

The carrier reproducing circuit 605 has a structure using, for example, a phase locked loop. The received signal and the synchronization-dedicated spreading code PN0 are multiplied by the multiplier. After the synchronization is established, the clock and code phase of the synchronization-specific spreading code in the received signal and the reference-specific synchronization-specific spreading code PN0 match, and the transmission-side synchronization-specific spreading code is not modulated with data. Is despread at, and a carrier component appears at the output. The output is then input to a bandpass filter, and only the carrier component is extracted and output. The output is then input to a well-known phase-locked loop consisting of a phase detector, a loop filter and a voltage controlled oscillator, and a phase is applied to a carrier component output from the voltage controlled oscillator through a bandpass filter. The locked signal is output as a reproduced carrier wave.

The reproduced carrier wave is input to the baseband demodulation circuit 606. The baseband demodulation circuit 606 generates a baseband signal from the reproduced carrier wave and the output of the high frequency signal processing unit 602. The baseband signal is divided into n pieces and despreaded for each code division channel by the spreading code groups PN1 to PNn output from the spreading code generator 604, and subsequently data demodulation is performed. The parallel demodulated n demodulated data is converted into serial data by the parallel-serial converter 607, and the signal input to the transmission device is output.

In this embodiment, binary modulation is used, but other modulation methods such as quadrature modulation may be used. Further, the present invention can be applied to any of the DS (direct spread) method, the FH (frequency hopping) method, and the TH (time hopping) method in a spread spectrum communication system.

Further, in the above embodiment, the transmitter and the receiver are described as separate bodies, but mutual communication can be performed by using different codes of the used code strings. In that case, the same package is used. The transmission device and the reception device, and by making the spreading code for synchronization different, it is possible to perform communication with substantially the same configuration using the same carrier, the receiving device, the surface acoustic wave device described above. Since it is possible to prevent mixing of high-level noise and direct signal from the internal transmission device and achieve synchronization establishment at high speed and reliably, it is possible to realize a highly reliable communication system.

[0074]

As described above, according to the present invention, a surface acoustic wave element having an input / output electrode for transmitting and receiving a surface acoustic wave formed on the main surface of a piezoelectric substrate, and the surface acoustic wave. An elastic surface including a package stem in which an element is encapsulated, the package stem having an input lead pin for extracting an input signal and an output lead pin for extracting an output signal, and a printed circuit board for mounting the package stem. In the wave device, a configuration is formed in which a part of the printed board is convexly projected so as to partition between the input lead pin and the output lead pin on the surface of the printed board on which the package stem is mounted. Thus, a direct signal that propagates through a slight gap between the package stem and the printed board and reaches the output lead pin is transmitted to the conductive material. Ri can be suppressed, noise floor is reduced convolution output waveform, it becomes easy to detect the convolution output signal.

Further, such a surface acoustic wave device is used in a receiving device and a communication system, and is used in a synchronization detection circuit for capturing and tracking a synchronization signal synchronized with a spread code of a received signal, thereby separating input / output signals. However, noise can be suppressed, a convolution signal with a high correlation peak can be obtained, and a baseband signal can be reproduced by multiplying the synchronization signal by the received signal, so a stable and highly reliable demodulated signal can be obtained. Obtainable.

[Brief description of drawings]

FIG. 1 is a schematic view showing a first embodiment of a surface acoustic wave device according to the present invention.

FIG. 2 shows a state in which a package stem 9 sealed by a sealing cap 10 is mounted on a printed circuit board 14,
It is the schematic seen from the direction of the arrow of FIG.

FIG. 3 is a schematic view showing a second embodiment of the surface acoustic wave device according to the present invention.

FIG. 4 shows a state in which a package stem 9 sealed by a sealing cap 10 is mounted on a printed board 14,
It is the schematic seen from the direction of the arrow of FIG.

FIG. 5 is a schematic view showing a third embodiment of the surface acoustic wave device according to the present invention.

FIG. 6 shows a state in which a package stem 9 sealed by a sealing cap 10 is mounted on a printed circuit board 14,
It is the schematic seen from the direction of the arrow of FIG.

FIG. 7 is a schematic perspective view showing a conventional surface acoustic wave device.

FIG. 8 shows a state in which a package stem 9 sealed by a sealing cap 10 is mounted on a printed circuit board 14,
It is the schematic seen from the direction of the arrow of FIG.

FIG. 9 is a block diagram showing an example of a communication system using the surface acoustic wave device of the present invention.

FIG. 10 is a block diagram showing an example of a transmitter of a communication system using the surface acoustic wave device of the present invention.

FIG. 11 is a block diagram showing an example of a receiver of a communication system using the surface acoustic wave element of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Piezoelectric substrate 2,3 Comb-shaped input electrode formed on the surface of the piezoelectric substrate 1 4 Output electrodes formed on the surface of the piezoelectric substrate 1 5a, 5b Input bonding wire 6 Output bonding wire 7a, 7b Input lead pin 8 Output Lead pin 9 Package stem 10 Sealing cap 11a, 11b Input side external circuit unit 12 composed of matching circuit, filter, amplifier, etc. 12 Output side external circuit unit 13a, 13b composed of matching circuit, filter, amplifier, etc. Lead pin Land pattern for soldering 14 Printed circuit board 15a, 15b Input terminal 16 Output terminal 17 Gap between package stem 9 and printed circuit board 19 Convex protrusion 20 Conductive rubber 21 Solder 40 Transmitter 41 Receiver 401 Transmitter Antenna 411 Receiving antenna 412 High frequency signal Processing unit 413 Synchronization circuit 414 Code generator 415 Spreading demodulation circuit 416 Demodulation circuit 501 Serial-parallel conversion for converting data input in series into n parallel data 502-1 to n Multiplier group 503 Spreading code generator 504 Addition 505 High-frequency stage 506 Transmitting antenna 601 Receiving antenna 602 High-frequency signal processing unit 603 Synchronizing circuit 604 Spreading code generator 605 Carrier reproducing circuit 606 Baseband demodulating circuit 607 Parallel-serial converter

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takahiro Hachisu 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Akira Torizawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Akane Yokota 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (11)

[Claims] 1. A surface acoustic wave element having an input / output electrode for transmitting and receiving a surface acoustic wave formed on a main surface of a piezoelectric substrate; and an input for extracting an input signal, in which the surface acoustic wave element is enclosed. In a surface acoustic wave device comprising a package stem having a lead pin for output and an output lead pin for extracting an output signal, and a printed circuit board for mounting the package stem, wherein the package stem of the printed circuit board is A surface acoustic wave characterized in that a convex protrusion is formed by convexly projecting a part of the printed board so as to partition between the input lead pin and the output lead pin on the surface to be mounted. apparatus. 2. The input lead pin and the output lead pin of the package stem are provided in opposite directions with the elastic surface element sandwiched therebetween, and on the surface of the printed board on which the package stem is mounted, 2. The surface acoustic wave device according to claim 1, wherein a convex protrusion is formed by protruding a part of the printed circuit board so as to cross between the input lead pin and the input lead pin. . 3. A surface acoustic wave element having an input / output electrode for transmitting and receiving a surface acoustic wave formed on a main surface of a piezoelectric substrate; and an input for extracting an input signal in which the surface acoustic wave element is enclosed. A surface acoustic wave device comprising a package stem having a lead pin for output and an output lead pin for extracting an output signal, and a printed circuit board for mounting the package stem, wherein the package stem is mounted. A surface acoustic wave device, wherein a conductive material is arranged on the surface of a printed circuit board so as to partition the input lead pin and the output lead pin. 4. The input lead pin and the output lead pin of the package stem are provided in opposite directions with the elastic surface element sandwiched therebetween, and on the surface of the printed board on which the package stem is mounted, The surface acoustic wave device according to claim 3, wherein the conductive material is arranged so as to cross between the input lead pin and the input lead pin. 5. The conductive material is at least one of conductive rubber, a metal plate, a conductive resin mold, a conductive film, and a non-conductive plate coated with a conductive film. The surface acoustic wave device according to claim 3 or 4. 6. The shape of the convex protrusion or the conductive material formed to partition between the input lead pin and the output lead pin on a surface of the printed circuit board on which the package stem is mounted. 7. The input lead pin and the output lead pin are formed so as to surround the input lead pin and the output lead pin, respectively, on a surface of the printed circuit board on which the package stem is mounted. The surface acoustic wave device according to claim 1. 7. The elastic surface according to claim 1, wherein the convex protrusion or the conductive material is formed so as to contact the bottom surface of the package stem. Wave device. 8. The back surface of the package stem and the ground surface provided on the main surface of the printed circuit board are formed so as to be in contact with each other via the convex protrusion or the conductive material. 8. The method according to claim 1, which is characterized in that
The surface acoustic wave device according to item. 9. A surface acoustic wave convolver element is used as the surface acoustic wave element.
The surface acoustic wave device according to claim 1. 10. A receiving device, wherein the surface acoustic wave device according to claim 1 is used in a synchronizing circuit for synchronizing a received signal. 11. A communication system using the surface acoustic wave device according to claim 1 for a synchronization circuit for establishing synchronization on the receiving side.