JPH0936699A - Surface acoustic wave device, receiving device and communication device using the same - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a smaller surface acoustic wave device, a receiving device, and a communication device by reducing the ratio of the mounting area of the printed circuit board of the surface acoustic wave device. A surface acoustic wave element having input / output electrodes for transmitting and receiving surface acoustic waves formed on a main surface of a piezoelectric substrate,
The surface acoustic wave device is encapsulated, and a 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 board for mounting the package stem are included. In this surface acoustic wave device, at least one of the input-side external circuit connected to the input lead pin and the output-side external circuit connected to the output lead pin is formed in the area where the package stem of the printed circuit board is mounted. It is characterized by being.

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, and a receiving device and a communication device using the same, and in particular, a surface acoustic wave element formed on a piezoelectric substrate is mounted on a package stem and integrated. The present invention relates to a surface acoustic wave device having a package stem mounted on a printed circuit board, and a receiving device and a communication device using the surface acoustic wave device in a synchronizing circuit for synchronizing a received signal.

[0002]

2. Description of the Related Art A surface acoustic wave is a surface acoustic wave propagating along the surface or boundary surface of a propagation medium such as a piezoelectric substrate, and its energy is mostly contained within about one wavelength from the surface, and a relatively small input. High-density elastic energy can be easily obtained even with power, and the nonlinear effect becomes larger than that of bulk waves, 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.

5 and 6 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.

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 for use, but in FIG. In order to make it easier to understand
It is described in a state of being floated from 4.

FIG. 6 is a schematic view showing a state where the package stem 9 sealed by the sealing cap 10 is 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 the carrier frequency ω is input to the input terminal 15a, the signal is transmitted to the input side external circuit portion 11a, the input lead pin 7a, and the input bonding wire 5b. It reaches the comb-shaped input electrode 3 via the surface of the comb-shaped input electrode 3, and a surface acoustic wave is excited on the comb-shaped input electrode 3 by the piezoelectric effect of the piezoelectric substrate 1. Similarly, when an electric signal of carrier frequency ω is input to the input terminal 15b, the signal reaches the comb-shaped input electrode 2 via the input side external circuit portion 11b, the input lead pin 7b, and the input bonding wire 5a, A surface acoustic wave is excited on the comb-shaped input electrode 2 by the piezoelectric effect of the piezoelectric substrate 1.

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, convolution (frequency 2ω) of these two surface acoustic waves occurs due to the physical nonlinear effect of the piezoelectric substrate 1. Explaining this action in more detail, a surface acoustic wave (angular frequency ω, wave number k) is excited from the comb-shaped input electrode 2 and a surface acoustic wave (angular frequency ω, wave number-k) is excited from the comb-shaped input electrode 3, respectively. ,
If they are superposed under a flat plate-shaped electrode provided in the center and the energy of the surface acoustic wave is more than a predetermined value, the product of two surface acoustic waves is performed by the elastic and piezoelectric nonlinear characteristics of the piezoelectric substrate that is the propagation medium. In the output electrode 4, which is the central electrode, two sets of non-linear terms of (2ω, 0) whose frequency is double and (0, 2k) whose frequency is 0 are generated. The component whose frequency is 2ω is
Since the wave number is 0, that is, the wavelength is infinite, the flat plate output electrode 4 at the center can extract it as an electric signal. The convolution thus generated is taken out as an electric signal from the output terminal 16 via the output electrode 4, the output bonding wire 6, the output lead pin 8 and the output side external circuit section 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.

The mechanism of such convolution is described in detail in, for example, "Shibayama," Application of Surface Acoustic Wave ", Television, 30.457 (1976)" and the like.

The surface acoustic wave device using the surface acoustic wave convolver is mainly used as one component of a receiving circuit of a communication system using a spread spectrum communication system. Therefore, in reality, the signals input to the comb-shaped input electrodes 2 and 3 are spread-spectrum modulated by a spread code having a certain period. In order to obtain a convolution output, the convolver must have an output electrode 4 having a length corresponding to the period length of the spreading code. When the surface acoustic wave having the above-mentioned spread code period length is excited from both comb-shaped input electrodes 2 and 3, the spread code sequence is arranged in the entire lengthwise region of the output electrode 4 during the spread code period length. , The maximum level convolution signal can be obtained from the output electrode when the code strings from both comb-shaped input electrodes 2 and 3 match.

[0014]

However, the velocity of the surface acoustic wave is an extremely slow velocity of about 10 ⁻⁵ as compared with the velocity of the electromagnetic wave (3 × 10 ⁸ m / s). The physical length of the output electrode corresponding to the cycle length becomes large.

For example, when a Y-cut Z-propagation lithium niobate substrate is used as the piezoelectric substrate, the velocity of the surface acoustic wave in the Z-axis direction is about 3488 [m / s], and the period of the diffusion code is 12 [. .mu.sec], the length of the output electrode becomes about 42 [mm].

If the output electrode length is not large, the size of the surface acoustic wave convolver inevitably becomes large, and as a result, the mounting area area for the printed circuit board 14 becomes large as shown by reference numeral a in FIG. There was a problem that it was difficult.

[0017]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a smaller surface acoustic wave device by reducing the mounting area of the surface acoustic wave device on the printed circuit board.

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, at least one of the input-side external circuit connected to the input lead pin and the output-side external circuit connected to the output lead pin is within the area where the package stem of the printed circuit board is mounted. It is characterized by being formed.

[0019]

According to the structure of the present invention, since the input side external circuit and the output side external circuit are formed in the area where the package stem is mounted on the printed circuit board, the mounting area is smaller than that of the package stem. Just the size,
The entire device can be downsized accordingly.

[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 on the surface of the piezoelectric substrate 1, 4 is an output electrode formed on the surface of the piezoelectric substrate 1, and 5a and 5b are A
An input bonding wire made of a thin wire such as L, Au, Cu or tin, or an alloy thereof, 6 is an output bonding wire, and 7a and 7b are input lead pins having a ribbon shape, a gull wing lead shape, or the like, Reference numeral 8 is an output lead pin of the same form, 9 is a package stem made of a conductor, 10 is a sealing cap, 11a and 11b are matching circuits for sequentially matching from the input lead pins 7a and 7b side, and a predetermined band is filtered. An input-side external circuit unit configured by any one or a combination of a filter, an amplifier that amplifies with a predetermined gain, and the like, an output-side external circuit unit 12 configured by, for example, a matching circuit, a filter, an amplifier, and the like
a and 13b are lead pin soldering land patterns for soldering and grounding other than the lead pins 7 and 8, and 14 is a board in which synthetic resin such as phenol-based, epoxy-based or silicon-based resin and paper, glass, synthetic fiber, etc. are combined, A printed circuit board having electrolytic copper foil adhered thereto and etched into a predetermined pattern, 15a and 15b are input terminals to which, for example, spread code signals are input, 16 is an output terminal to output a convolution signal, and 17 is a printed circuit board 14. Is a through hole for electrically connecting the patterns formed on the front and back surfaces of.

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 so-called 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 on which the surface acoustic wave convolver is mounted is used by being mounted on the printed board 14 together with the input side external circuit portions 11a and 11b and the output side external circuit portion 12, but in FIG. The package stem 9 to the printed circuit board 14 for easy understanding.
The land pattern 1 for the lead pins 7 and 8 and the lead pin soldering of the printed circuit board 14 is described in a state of being more floated.
3 and 3 are connected by soldering.

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 package stem 9 is mounted on the surface of the printed circuit board 14 corresponding to the surface on which the package stem 9 is mounted.
In the area (a) where is mounted, the input side external circuit unit 11
a, 11b and the output side external circuit section 12 are the printed circuit board 1
4 is soldered to the back surface copper foil of 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 input to the input side external circuit portion 11a, the input lead pin 7a, and the input bonding wire 5b. It reaches the comb-shaped input electrode 3 via the surface of the comb-shaped input electrode 3, and a surface acoustic wave is excited on the comb-shaped input electrode 3 by the piezoelectric effect of the piezoelectric substrate 1. Similarly, when an electric signal of carrier frequency ω is input to the input terminal 15b, the signal reaches the comb-shaped input electrode 2 via the input side external circuit portion 11b, the input lead pin 7b, and the input bonding wire 5a, A surface acoustic wave is excited on the comb-shaped input electrode 2 by the piezoelectric effect of the substrate. The other electrodes of the comb-shaped input electrodes 2 and 3 are wire-bonded to the package stem 9 and grounded.

These two input surface acoustic waves propagate in opposite directions on the piezoelectric substrate 1 while being confined in the output electrode 4 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) occurs. The convolution signal thus generated is taken out as an electric signal from the output terminal 16 through the output electrode 4, the output bonding wire 6, the output lead pin 8, the through hole 17, and the output side external circuit section 12.

The surface acoustic wave device using the surface acoustic wave convolver is mainly used as one component of the receiving circuit of the communication system using the spread spectrum communication system. Therefore, in reality, the signals input to the comb-shaped input electrodes 2 and 3 are spread-spectrum modulated by a spread code having a certain period. In order to obtain a convolution output, the surface acoustic wave convolver must have an output electrode having a length corresponding to the period length of the spread code.

Here, as the length of the waveguide electrode of the output electrode 4 increases, the size of the surface acoustic wave convolver increases and the size of the package stem 9 increases, but the external circuit portions 11a, 11b on the input side and the external side on the output side are increased. Circuit part 1
2 is formed in the area (a) where the package stem 9 is mounted on the surface of the printed board 14 opposite to the surface on which the package stem 9 is mounted, the mounting area is equal to the size of the package stem 9. The whole device can be downsized accordingly.

As a result, especially from the output electrode 4 to the output terminal 1
The physical distance to 6 is shortened, and the degree of spatial noise wave mixing is reduced. In particular, since the signal level of the convolution signal taken out from the output electrode is low, for example, when the convolution output signal is used as a correlator for establishing the synchronization of the surface acoustic wave device in the spread spectrum communication system, noise is generated. Since the interference of the components can be suppressed and therefore a signal having a correlation peak with a good S / N can be obtained, the synchronization signal can be acquired quickly and stably, and the establishment of synchronization is ensured.

In this embodiment, the surface mount type is shown as the package stem 9. However, other package stems, for example, package stems in which lead pins are inserted into the printed circuit board or solder balls are used. BGA (Ball Grid Arra)
y) 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, 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.

[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. Figure 3,
In FIG. 4, reference numerals 11a 'and 11b' denote some circuit portions of the input side external circuit portions 11a, 11b, and 12 'denote some circuit portions of the output side external circuit 12.

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 a package stem 9 of a conductor and used. 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 containing the surface acoustic wave convolver is part of the input side external circuit portion 11a, 1a.
1b and a part 12 of the output side external circuit portion are mounted and used on a printed circuit board 14, but in FIG. 3, the package stem 9 is shown in a state of being floated from the printed circuit board 14 for easy understanding of the present invention. are doing.

The printed circuit board 14 includes 14a, 14
It is a multi-layered substrate composed of b and 14c, and in FIG. 3, the respective layers are illustrated in a separated state in order to facilitate understanding of the present invention.

FIG. 4 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. 3 and 4, in the area (a) where the package stem 9 of the multilayer printed circuit board 14 is mounted, the input side external circuit portion is provided on the back surface of the printed board 14a. Circuit parts 11a 'and 11b', which are a part of 11a and 11b, are formed by microstrip lines, and they are provided on the back surface of the printed board 14c via the printed board 14b and the through hole 17 and the input side external circuit part. The other parts 11a and 11b are connected to the input terminals 15a and 15b.

Further, the output side external circuit portion 1 is provided on the back surface of 14b.
The circuit part 12 ′ that is a part of 2 is formed by a microstrip line, and they are connected to each other through the through hole 17.
It is connected to the other component 12 of the output side external circuit portion provided on the back surface of c and is connected to the output terminal 16.

Further, the surface of 14b has through holes 17
Except for the parts, the entire surface is covered with copper foil and grounded.

Also in the surface acoustic wave device having such a structure, as in the first embodiment, the input side external circuit section 11 is provided.
Since the a and 11b and the output side external circuit portion 12 are formed in the area (a) of the printed board 14 where the package stem 9 is mounted, the mounting area is small.
The size of the entire device can be reduced accordingly.

Further, in the present embodiment, in the area (a) where the package stem 9 of the multilayer printed circuit board 14 is mounted, it is a part of the input side external circuit portion 11.
a ', 11b' and a part of the output side external circuit 1
Since 2'is formed as a microstrip line on each layer of the printed circuit board 14, the number of steps for mounting the components of the input / output external circuit section at the time of production is reduced, and the yield can be increased accordingly.

The circuit parts 11a 'and 11b' which are a part of the input side external circuit part and the circuit part 12 'which is a part of the output external circuit are formed on different layers on the multilayer printed circuit board 14, respectively. For example, in FIGS. 3 and 4, the circuit portions 11a ′ and 11b ′ are formed on the back surface of 14a, and the circuit portion 12 ′ is formed on the back surface of 14b, and a ground layer (FIGS. 14b) is provided, unnecessary electromagnetic coupling between the input side external circuits 11a 'and 11b' and the output side external circuit 12 'can be suppressed, and a stable output signal can be obtained accordingly.

In this embodiment, the surface mount type is shown as the package stem 9, but a package stem other than this, for example, a type in which lead pins are inserted into a printed circuit board may be used. At this time, the back side of the printed board 14a is connected to the circuit sections 11a 'and 11b' of the input side external circuit section, or the back side of the printed board 14b is connected to the circuit section 12 'of the output side external circuit section.

Further, in this embodiment, the circuit parts 11a 'and 11b' which are a part of the input side external circuit part are formed on the back surface of the multilayer printed circuit board 14a, and the multilayer printed circuit board 1 is formed.
Although the example in which the circuit portion 12 'which is a part of the output external circuit is formed on the back surface of 4b is shown, it may be formed on a layer other than those or not limited to a three-layer printed circuit board. .

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.

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.

In the above embodiments, the surface acoustic wave element is an elastic convolver. However, in general, the surface acoustic wave element has other excellent characteristics such as a bandpass filter, a matched filter and a delay circuit. Since it has a communication device,
It is widely used in receiving devices and the like, and the same configuration as that of the embodiment according to the present invention may be applied to prevent mixing of input / output waves and to reduce size in mounting.

[Third Embodiment] FIG. 7 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 synchronization circuit 413 is the above-mentioned first and second circuits of the present invention.
The surface acoustic wave device 4131 shown in the second embodiment, the modulation circuit 4132 for modulating the reference spread code input from the code generator 414, and the signal output from the surface acoustic wave device 4131 are processed, The signal processing circuit 4133 outputs a spread code signal and a clock synchronization signal for the transmission signal to the code generator 414. Surface acoustic wave device 413
1, the output signal from the high frequency signal processing unit 412 and the output signal from the modulation circuit 4132 are respectively filters,
Input to the surface acoustic wave device via the amplifier and matching circuit,
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 spread code having the same clock and spread code phase as the spread 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 Keying)
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.

Surface acoustic wave device 4131 used in this configuration
Has a miniaturized structure, and can sufficiently contribute to miniaturization of the entire receiving apparatus. Further, for example, the modulation circuit 413 is provided in the input-side external circuit section 11a of the surface acoustic wave device 4131.
2 and the signal processing circuit 4133 is included in the output side external circuit section 12 and mounted on the printed circuit board 14, it is possible to further contribute to downsizing of the device.

[Fourth Embodiment] FIGS. 8 and 9 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. 8, which shows a block diagram of a transmission device, 501 is a serial-parallel converter that converts serially input data into n parallel data, and 502-1 to n are parallelized data and spread code generator. A group of multipliers for multiplying the n spreading codes output from 503 by n different spreading codes PN
1 to PNn and a spreading code generator for generating a spreading code PN0 dedicated to synchronization, and 504 adds the spreading code PN0 dedicated to synchronization output from the spreading code generator 503 and n outputs of the multiplier groups 502-1 to 502-1. 505 is a high frequency stage for converting the output of the adder 504 into a transmission frequency signal,
6 is a transmitting antenna.

Further, in FIG. 9 showing a block diagram of the receiving apparatus, 601 is a receiving antenna, 602 is a high frequency signal processing section, 603 is a synchronizing circuit for capturing synchronization with the spread code and clock on the transmitting side and maintaining synchronization tracking, Reference numeral 604 is a spread code generator for generating n + 1 spread codes and reference spread codes, which are the same as the spread code group on the transmission side, in response to the code synchronization signal and the clock signal input from the synchronization circuit 603.
Reference numeral 05 is a carrier reproduction circuit for reproducing a carrier signal from the carrier reproduction spread code PN0 output from the spread code generator 604 and the output of the high frequency signal processing unit 602, and 606 is the output of the carrier reproduction circuit 605 and the high frequency signal processing unit 602.
Of the baseband demodulation circuit 6 and the output of the spreading code generator 604 using the n spreading codes PN1 to PNn.
It is a parallel-to-serial converter that performs parallel-to-serial conversion of n pieces of parallel demodulated data output from 06.

In the above configuration, on the transmission side, the input data is first converted by the serial-parallel converter 501 into n pieces of parallel data equal to the number of code division multiplexes. 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 the 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.

As the surface acoustic wave device 6031, any one of the surface acoustic wave convolver elements shown in the first and second embodiments is used, and the output signal from the high frequency signal processing unit 602 and the output signal from the modulation circuit 6032 are used. Is input and the convolution operation of the two input signals is performed. Here, if the code sequence of the reference spreading code input from the code generator 604 to the modulation circuit 6032 is a code sequence obtained by time-reversing the synchronization-only spreading code transmitted from the transmission side, the surface acoustic wave device 6031 receives A correlation peak is output when the code string of the synchronization-specific spreading code component and the code string of the reference spreading code included in the signal match on the waveguide of the output electrode of the surface acoustic wave device 6031.

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 code synchronization signal and the clock signal 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 is constructed by using, for example, a circuit utilizing 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.

In the above embodiment, the surface acoustic wave device 6 is used.
Although 031 is described as the surface acoustic wave device shown in the first and second embodiments, the entire synchronizing circuit 603 of this embodiment may be mounted on the same printed circuit board 14. That is, in the surface acoustic wave device, the modulation circuit 6033 is included in one of the input external circuit units 11a and 11b, and the signal processing circuit 6033 is included in the output external circuit unit 12, so that the surface acoustic wave device can be downsized. There is no need for further miniaturization. By doing so, it is possible to contribute to downsizing of the entire communication device. Further, a part of the high frequency signal processing unit 602 is input to the external circuit units 11a and 1a.
By including it in the other side of 1b, it is possible to further reduce the size, and it is possible to prevent external interference noise from being mixed due to the shortening of the connection line, which is also effective in improving the performance characteristics.

Further, in the above embodiment, the transmitting device and the receiving device are described as separate bodies, but mutual codes can be carried out by using different codes in the used code strings. In that case,
The transmitter and the receiver are provided in the same package, and by using different spreading codes for synchronization, it is possible to perform communication with substantially the same configuration using the same carrier, and the receiver is the same as the above-mentioned small-sized one. Since the mixed surface acoustic wave device can be used to prevent high-level noise from being mixed in from the internal transmission device and the synchronization can be established at high speed and reliably, a highly reliable communication system is enabled.

[0072]

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, at least one of the input-side external circuit connected to the input lead pin and the output-side external circuit connected to the output lead pin is formed in the area where the package stem of the printed circuit board is mounted. With the configuration, the input side external circuit and the output side external circuit are provided in the area where the package stem of the printed circuit board is mounted. Because it is made, the mounting area need only the size of the package stem, can correspondingly downsize the entire device.

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 the spread code of the received signal, thereby reducing the size of the signal line. By shortening the exposed part, it is possible to suppress the mixing of external noise, obtain a convolution signal with a high correlation peak, and multiply the synchronization signal with the received signal to reproduce the baseband signal, so that stable and stable A demodulated signal with high reliability can be obtained.

[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 perspective view showing a conventional surface acoustic wave device.

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

FIG. 8 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. 9 is a block diagram showing an example of a receiver of a communication system using the surface acoustic wave device of the present invention.

[Explanation 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, 11a ', 11b, 11b' Input side external circuit section 12 'consisting of matching circuit, filter, amplifier etc. 12' 12 Composed of matching circuit, filter, amplifier etc. Output side external circuit section 13a, 13b Lead pin soldering land pattern 14, 14a, 14b, 14c Printed circuit board 15a, 15b Input terminal 16 Output terminal 17 Through hole 40 Transmitter 41 Receiver 401 Transmitter antenna 411 Receiver antenna 412 High frequency Signal processing unit 413 Synchronous circuit 414 Code Generator 415 Spread demodulation circuit 416 Demodulation circuit 501 Serial-parallel converter 502-1 to n for converting data input in series to parallel data 501-n Multiplier group 503 Spread code generator 504 Adder 505 High frequency stage 506 Transmission Antenna 601 Reception antenna 602 High frequency signal processing unit 603 Synchronization circuit 604 Spreading code generator 605 Carrier regeneration circuit 606 Baseband demodulation 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 (10)

[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. 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, which is connected to the input lead pin. At least one of an input-side external circuit and an output-side external circuit connected to the output lead pin is formed in an area of the printed circuit board where the package stem is mounted. 2. The elastic surface according to claim 1, wherein the input-side external circuit and the output-side external circuit are configured by at least one of a matching circuit, a filter, an amplifier, or a combination thereof. Wave device. 3. At least one component of an input side external circuit connected to the input lead pin and an output side external circuit connected to the output lead pin faces a surface of the printed board on which the package stem is mounted. The surface acoustic wave device according to claim 1, wherein the surface acoustic wave device is formed on a surface in an area where the package stem is mounted. 4. The printed circuit board on which the package stem and the external circuits on the input side and the output side are mounted is a multilayer board, and the printed circuit board is mounted on a layer between a surface on which the package stem is mounted and a back surface thereof. The surface acoustic wave device according to claim 1, wherein at least one component of an input side and an output side external circuit is formed. 5. The printed board on which the package stem and the external circuits on the input side and the output side are mounted is a multi-layer board, and the printed board is mounted on a layer between a surface on which the package stem is mounted and a back surface thereof. At least one component of the input side external circuit and at least one component of the output side external circuit,
The surface acoustic wave device according to any one of claims 1 to 4, wherein the surface acoustic wave device is formed on different layers of the multilayer substrate. 6. The printed board on which the package stem and the external circuits on the input side and the output side are mounted is a multilayer board, and the surface on which the package stem is mounted and the external circuits on the input side and the output side are mounted. The surface acoustic wave device according to any one of claims 1 to 5, wherein at least one ground layer is provided in a layer between the surface to be formed. 7. The at least one of the input side external circuit and the output side external circuit is formed by a microstrip line formed on a layer of the printed board. The surface acoustic wave device according to claim 1. 8. A surface acoustic wave convolver element is used as the surface acoustic wave element.
The surface acoustic wave device according to claim 1. 9. A receiving device, wherein the surface acoustic wave device according to claim 1 is used in a synchronizing circuit for synchronizing with a received signal. 10. A communication device comprising the surface acoustic wave device according to claim 1 in a receiver.