JP2001024545A - Ask modulating/demodulating radio equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute transmission and reception with a single antenna by providing a transmission/reception control circuit for turning on the power source of a low noise amplification amplifier, turning off the power source of a transmission power amplifier at the time of reception, and turning off the power source of the low noise amplifier and turning on the power source of the transmission power amplifier at the time of transmission. SOLUTION: A transmission/reception control circuit 17 switches a connecting path of an antenna at the time of reception and at the time of transmission to realize time division multiplexing transmission and reception. At the time of transmission, the power source of a low noise amplifier circuit 3 of a receiving system is turned off to reduce feedback quantity of a transmission wave via a switch circuit 15, the circuit 3, a mixer 5 and a distributor 4 to suppress abnormal oscillation of a transmission system to secure stable operaton. In addition, at the time of reception, the connecting path of the circuit 15 is connected to a receiving side through use of a transmission/reception switching signal 123 and the power source of a power amplification amplifier 11 is turned off to secure isolation of the transmission system from the reception system to suppress detouring of transmission waves from the transmission system and receiving band noise to realize satisfactory receiving characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication field including mobile communication or an automatic toll collection system (ET).
The present invention relates to an ASK modulation / demodulation radio used in C).

[0002]

2. Description of the Related Art A conventional radio using an ASK modulation / demodulation system has a receiving antenna 1 for receiving a radio transmission signal 101 output from a roadside device, as shown in FIG. A first filter 2 for removing unnecessary components outside the band from the signal 102, a low-noise amplifier 3 for amplifying the first filter output 103, and a first filter 4 output from the distributor 4 to a low-noise amplifier output 104. A mixer 5 that mixes the local oscillation signal 105 and converts it into an intermediate frequency signal and outputs a mixer output 106;
06, a second filter 6 for removing unnecessary components outside the pass band, and a second filter output 107 are detected and demodulated to output an analog signal or digital signal 108 corresponding to the received electric field strength and a received baseband signal 109. A demodulation circuit 7 which receives the reference signal 110 as an input, a synthesizer circuit 8 which synchronizes with the reference signal 110 and outputs a local oscillation signal of an unmodulated signal corresponding to a transmission frequency as a synthesizer output 111, and the synthesizer output 111
Is distributed to the first local oscillation signal 105 and the second local oscillation signal 112, and the transmission baseband signal 113 is input to perform the band limitation of the transmission baseband signal 113, and the band is limited. ASK modulation circuit 9 that ASK modulates second local oscillation signal 112 with a transmission baseband signal and outputs a modulated signal as ASK modulation output 114, and inputs ASK modulation output 114 to output power at an antenna output end. A gain adjustment circuit 10 for adjusting the power and a transmission power amplifier 11 for amplifying the power of the gain adjustment output 115
Filter 12 and third filter 12 for removing unnecessary components other than signal components from transmission power amplifier output 116
It comprises a transmission antenna 13 for transmitting a transmission signal 117 outputted from the air to the air.

[0003]

However, A shown in FIG.
In the SK modem, two antennas, a receiving antenna and a transmitting antenna, are used.
An on-board wireless device such as an ETC system that requires two antennas and is required to be small in size including the antenna because the transmitting antenna and the receiving antenna must be arranged to some extent to ensure isolation between transmission and reception. In this case, the entire arrangement is very difficult, and it is difficult to reduce the size of the radio.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a small-sized ASK modem capable of performing transmission and reception with one antenna.

[0005]

In order to achieve the above object, an ASK modulation / demodulation radio according to the present invention is a low-noise amplification amplifier for reception by a vehicle-mounted radio which communicates with a roadside radio using a single transmitting / receiving antenna. And a transmission / reception control circuit that turns off the power of the transmission power amplifier, turns off the power of the low-noise amplifier during transmission, and turns on the power of the transmission power amplifier during transmission. According to this configuration, it is possible to realize a small-sized ASK modulation / demodulation wireless device that performs transmission and reception with one antenna.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is to turn on the power supply of the low-noise amplification amplifier at the time of reception by the on-vehicle wireless device performing communication with the roadside wireless device using one transmitting / receiving antenna. A power transmission and reception control circuit for turning off the power supply of the amplifier, turning off the power supply of the low noise amplification amplifier at the time of transmission, and turning on the power supply of the transmission power amplifier, so that the transmission wave passes through the reception circuit such as the low noise amplification amplifier and the mixer circuit. In this way, a feedback loop is formed to return to the transmission system to prevent deterioration of the characteristics of the transmission system and occurrence of abnormal oscillation, thereby enabling the transmission system to operate stably and obtain good characteristics. Also, transmission and reception can be performed by one antenna,
With the configuration of one antenna, there is an effect of eliminating the restriction on the arrangement of the transmitting antenna and the receiving antenna required for the isolation of transmission and reception, and realizing the miniaturization of the whole radio.

According to a second aspect of the present invention, a reception signal received from an antenna is mixed with an unmodulated local oscillation signal corresponding to the frequency of a transmission frequency signal output from a synthesizer circuit to produce an intermediate frequency signal. An on-vehicle wireless device having a mixer circuit for conversion, wherein the power of the mixer circuit is always turned on at the time of transmission and reception, and the local oscillation signal input side impedance of the mixer circuit connected to the transmission system at the time of transmission. It has an effect of suppressing the impedance fluctuation of the transmission system by keeping it constant, and enabling the transmission system to operate stably and obtain good characteristics.

According to a third aspect of the present invention, an antenna mounting portion for mounting an antenna element and a component other than the antenna are mounted on the same surface of the substrate on an n-layer (n ≧ 4) substrate. The antenna mounting part is separated from the component mounting part by providing an antenna mounting part other than the part mounting part, thereby reducing the influence from the component mounting part and improving the antenna's good directivity. Has the effect of ensuring the characteristics.

According to a fourth aspect of the present invention, there is provided a substrate having a four-layer structure, including a portion other than the first-layer antenna mounting portion and a portion other than the fourth-layer antenna mounting portion. It is a double-sided mounting structure for mounting components. An antenna element is mounted on the antenna mounting portion of the first layer, and the entire surface of the first layer antenna mounting portion other than the antenna feeding point is grounded.
The second layer is grounded as a whole, and the third layer is a ground plane and a plane for routing power and signal lines. By securing an antenna mounting part, good antenna characteristics are obtained, and parts are mounted on both sides. This has the effect of reducing the board area and further reducing the size of the entire wireless device.

According to a fifth aspect of the present invention, there is provided a filter having a function of removing unnecessary components outside a band from a reception signal received from the transmission / reception antenna or a transmission signal transmitted from the transmission / reception antenna. The filter is constituted by a half-wavelength strip line resonance type filter having a layer ground plane as a ground plane, and is arranged in an area corresponding to a fourth layer antenna mounting section. In this case, the height of the component mounting portion can be reduced by removing the component that controls the height in the component group, thereby realizing a reduction in the thickness of the entire wireless device.

According to a sixth aspect of the present invention, the antenna element is mounted such that an axis extending in a direction perpendicular to the component mounting portion from the antenna element feeding point is a symmetric axis of the antenna mounting portion. It is characterized in that it is mounted on a portion, and has an effect of realizing a better antenna directivity by setting the ground plane area around the antenna element to be equal to the left and right.

According to a seventh aspect of the present invention, there is provided the entire component mounting surface other than the antenna mounting portion on the antenna mounting surface side,
The antenna mounting surface is characterized in that it has a shield structure that shields the entire component mounting surface on the back surface when the antenna mounting surface is the front surface and cuts off the synthesizer circuit and other circuit blocks mounted on the same surface. By shielding the component mounting surface other than the surface, unnecessary radiation other than the transmission wave radiated from the antenna is reduced, and the antenna characteristic is prevented from deteriorating due to interference with the leaky wave. Also, by shielding the synthesizer circuit, the characteristic deterioration of the synthesizer circuit due to the intrusion of a transmission wave or the like is suppressed, thereby achieving an effect of realizing good transmission characteristics and reception characteristics.

According to an eighth aspect of the present invention, there is provided a substrate having a four-layer structure, wherein the first layer is an antenna element mounting surface and the entire area other than the antenna feeding point is ground, and the second layer is a ground plane and a power supply. , Signal line routing surface,
The third layer is a whole ground, and the fourth layer is a component mounting surface excluding an antenna element. By expanding a ground plane area serving as a ground of a fourth layer for mounting an antenna, it is possible to obtain better antenna directivity characteristics. It has the function of realizing the antenna gain.

According to a ninth aspect of the present invention, the antenna element is arranged on the central axis of one layer, and a more favorable antenna is provided by uniformly setting a ground plane area around the antenna element. It has an effect of realizing directional characteristics.

An antenna according to a tenth aspect of the present invention is characterized in that the antenna has a shield structure that shields the entire component mounting surface of the fourth layer and that blocks the synthesizer circuit and other circuit blocks. Shielding the component mounting surface other than the mounting surface reduces the unnecessary radiation other than the transmission wave radiated from the antenna, and has the effect of suppressing the deterioration of the antenna characteristics due to the interference with the leaky wave.
Also, by shielding the synthesizer circuit, the characteristic deterioration of the synthesizer circuit due to the intrusion of a transmission wave or the like is suppressed, thereby achieving an effect of realizing good transmission characteristics and reception characteristics.

(Embodiment 1) FIG. 1 shows a configuration diagram of an ASK modulation / demodulation radio according to Embodiment 1 of the present invention. FIG.
, A transmission / reception antenna 14 for receiving a radio transmission signal 101 output from the roadside device and transmitting a radio transmission signal 118 to the roadside device, and a reception signal 102 received from the transmission / reception antenna 14 or transmission output from the switch circuit 15 A first method for removing unnecessary components outside the band from the signal 119b
Based on the filter 16 and the switch control signal 120 output from the transmission / reception control circuit 17, the reception signal 119a received from the first filter 16 at the time of reception is output to the low-noise amplifier 3, and output from the transmission power amplifier 11 at the time of transmission. Switch circuit 15 that outputs the transmitted signal 121 to the first filter 16, the low-noise amplifier 3 that amplifies the received signal 122 output from the switch circuit 15, the low-noise amplifier output 104, and the first local oscillation. A mixer 5 for mixing the signal 105 and converting it into an intermediate frequency signal 106;
A second filter 6 for removing unnecessary components outside the pass band from the mixer output 106, and an analog or digital signal 108 and a reception baseband signal 10 corresponding to the received electric field intensity by detecting and demodulating the second filter output 107 and demodulating them.
A demodulation circuit 7 for outputting a reference signal 110 and a local oscillation signal of an unmodulated signal synchronized with the reference signal 110 and corresponding to the transmission frequency.
A synthesizer circuit 8 that outputs the signal as a signal; a distributor 4 that distributes a synthesizer output 111 to a first local oscillation signal 105 and a second local oscillation signal 112; ASK modulation circuit 9 that performs ASK modulation on second local oscillation signal 112 with a band-limited transmission baseband signal and outputs a modulated signal as ASK modulation output 114, and inputs ASK modulation output 114 Gain adjustment circuit 10 for adjusting the output power at the antenna output end and transmission power amplifier 11 for amplifying the power of gain adjustment output 115
, A switch control signal 120 and a power output of the low-noise amplifier turned on at the time of reception, and a power output of the power amplify amplifier. Off, turn off the power output of the low noise amplifier during transmission,
It comprises a transmission / reception control circuit 17 for turning on the power output of the power amplification amplifier.

In the ASK modulation / demodulation radio according to the first embodiment of the present invention, the transmission / reception control circuit 17 switches the connection path with the antenna at the time of reception and transmission to enable transmission and reception of time division multiplexing. By turning off the power supply of the low noise amplifier 3 of the receiving system, the switch circuit 1
5. It has an effect of suppressing abnormal oscillation of the transmission system and reducing the amount of feedback of the transmission wave passing through the low-noise amplifier 3, the mixer 5, and the distributor 4 to ensure stable operation. At the time of reception, the connection path of the switch circuit is connected to the reception side using the transmission / reception switching signal 123.
By turning off the power supply, the isolation between the transmission system and the reception system is ensured, and it is possible to suppress the transmission of the transmission wave from the transmission system and the reception band noise, thereby realizing good reception characteristics. Further, the mixer 5 always transmits and receives data.
By turning on the power supply, fluctuations in the input / output impedance of the distributor 4 can be suppressed, and deterioration of the characteristics of the transmission system can be prevented.

The switch circuit 15 according to the first embodiment
Can be composed of a pin diode and a GaAs FET. Further, by using a switch with a built-in PNP resistor for turning on and off the power supply of the low noise amplifier 3 and the power amplifier 11, it is possible to obtain high-speed rise and fall characteristics.

2 and 4, and FIGS. 3 and 5 show a board configuration diagram and a cross-sectional view of the board of the ASK modulation / demodulation radio according to the first embodiment of the present invention.

In FIG. 2, a four-layer board has an antenna mounting portion for mounting an antenna element on the same surface of the substrate and a component mounting portion for mounting components other than the antenna. This is a double-sided mounting structure in which components are mounted on portions other than the mounting portion and the entire surface of the fourth layer or portions other than the antenna mounting portion of the fourth layer. The antenna element is mounted on the first-layer antenna mounting portion, and the first-layer antenna mounting portion other than the antenna feeding point is entirely grounded, the second layer is entirely grounded, and the third layer is a ground surface and a power supply and signal line routing surface. And

In the first embodiment, by providing an antenna mounting portion other than the component mounting portion, the antenna mounting portion is separated from the component mounting portion, thereby reducing the influence of the component mounting portion and improving the directional characteristics of the antenna. Has the effect of ensuring.
Further, by mounting components on both sides, the board area can be reduced, and the wireless device can be further downsized.

Further, the first filter 16 is a half-wavelength strip line resonance type filter having a ground plane of a two-layer ground plane or a three-layer ground plane, and is disposed in a region corresponding to a fourth-layer antenna mounting part. As a result, the parts that dominate the height of the component group in the component mounting part, such as a multilayer filter, are removed, and the height of the component mounting part can be reduced, thereby realizing a thinner wireless device. It has the effect of doing.

Further, the antenna element is mounted on the antenna mounting portion such that an axis extending in a direction perpendicular to the component mounting portion from the antenna element feeding point is a symmetric axis of the antenna mounting portion, and a ground plane area around the antenna element is provided. Have the effect of realizing even better antenna directional characteristics by setting.

Then, as shown in FIG. 3, the entire component mounting surface other than the antenna mounting portion on the antenna mounting surface side of the first layer,
By shielding the entire component mounting surface of the fourth layer with a shield case, it has an effect of reducing unnecessary radiation other than a transmission wave radiated from the antenna and suppressing deterioration of antenna characteristics due to interference with a leaky wave. Further, by providing a shield structure for shielding the synthesizer circuit 8 from other circuit blocks mounted on the same plane in the shield case, it is possible to suppress deterioration in characteristics of the synthesizer circuit 8 due to transmission wave dive and the like. It has an effect of realizing transmission characteristics and reception characteristics.

Next, as shown in FIG. 4, a substrate having a four-layer structure is used. The first layer is the surface on which the antenna element is mounted, and the entire area other than the antenna feeding point is grounded. The antenna is mounted by forming a layer configuration in which the routing surface and the third layer are grounded on the entire surface and the fourth layer is a component mounting surface excluding the antenna element.
It is possible to increase the area of the ground plane, which is the ground of the layer, and realize more favorable antenna directivity and antenna gain.

Further, by arranging the antenna element on the central axis of one layer and uniformly setting the area of the ground plane around the antenna element, more favorable antenna directivity can be realized.

In addition, as shown in FIG. 5, as in the case of the double-sided mounting structure shown in FIG. 3, the entire component mounting surface of the fourth layer is shielded to shield the component mounting surfaces other than the antenna mounting surface. By doing so, it is possible to reduce unnecessary radiation other than the transmission wave radiated from the antenna and to suppress deterioration of antenna characteristics due to interference with leaky waves, and to shield the synthesizer circuit 8 from other circuit blocks. By having the structure, it is possible to suppress the characteristic deterioration of the synthesizer circuit 8 due to the dive of a transmission wave or the like, and to realize good transmission characteristics and reception characteristics.

[0028]

As described above, according to the present invention, a low-noise amplifier and a power control circuit for a transmission power amplifier are attached, so that communication with the roadside apparatus can be performed by one transmission / reception with a minimum number of attached circuits. It is possible to realize an in-vehicle wireless device using an antenna, and furthermore, by configuring the antenna mounting part separately from the component mounting part having the shield structure on the same substrate, it is possible to suppress the deterioration of the antenna characteristics and achieve a good antenna An advantageous effect that enables realization of a small in-vehicle wireless device having directivity is obtained.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of an ASK modulation / demodulation radio according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a configuration of a substrate layer of the ASK modem in the embodiment.

FIG. 3 is a cross-sectional view of a configuration of a substrate layer of the ASK modulation / demodulation wireless device of the embodiment.

FIG. 4 is an exploded perspective view showing a configuration of a substrate layer of another ASK modem in the embodiment.

FIG. 5 is a configuration sectional view of a substrate layer of another ASK modulation / demodulation radio device of the embodiment.

FIG. 6 is a circuit diagram showing a configuration of a conventional ASK modulation / demodulation radio.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Receiving antenna 2, 16 1st filter 3 Low-noise amplifier 4 Distributor 5 Mixer 6 2nd filter 7 Detection and demodulation circuit 8 Synthesizer circuit 9 ASK modulation circuit 10 Gain adjustment circuit 11 Transmission power amplifier 12 Third filter 13 Transmission antenna 14 transmission / reception antenna 15 switch circuit 17 transmission / reception control circuit 101 wireless transmission signal 102 reception signal 103,119 first filter output 104 low noise amplification amplifier output 105 first local oscillation signal 106 mixer output (intermediate frequency signal) 107 2 Filter output 108 Analog signal or digital signal corresponding to reception electric field strength 109 Reception baseband signal 110 Reference signal 111 Synthesizer output 112 Second local oscillation signal 113 Transmission baseband signal 114 ASK modulation output 115) Gain adjustment output 116 Transmission power amplifier output 117 Transmission signal 118 Radio transmission signal 119a Reception signal 119b Transmission signal 120 Switch control signal 121 Power amplification amplifier output 122 Reception signal switch output 123 Transmission / reception switching signal 124 Power supply for low noise amplification amplifier 125 Power supply for power amplifier

Continued on the front page (72) Inventor Yoshikuni Fujihashi 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5K011 AA00 AA06 BA01 BA06 DA03 DA06 DA15 DA22 DA27 JA01 KA02 KA13

Claims (10)

[Claims] An on-vehicle wireless device that performs communication with a roadside wireless device using a single transmitting / receiving antenna turns on the power of a low-noise amplifier, turns off the power of a transmission power amplifier when receiving, and turns off the power of the low-noise amplifier when transmitting. An ASK modulation / demodulation radio having a transmission / reception control circuit for turning off power and turning on the power of the transmission power amplifier. 2. An on-vehicle wireless device having a mixer circuit for mixing a received signal received from an antenna with an unmodulated local oscillation signal corresponding to the frequency of a transmission frequency signal output from a synthesizer circuit and converting the signal into an intermediate frequency signal. 2. The ASK modulation / demodulation radio according to claim 1, wherein the power supply of the mixer circuit is always turned on at the time of transmission and reception. 3. A substrate having an n-layer (n ≧ 4) configuration, comprising: an antenna mounting portion for mounting an antenna element on the same surface of the substrate; and a component mounting portion for mounting components other than the antenna. The ASK modulation / demodulation radio device according to claim 1. 4. A double-sided mounting structure in which components are mounted on a portion other than the first-layer antenna mounting portion and on the entire fourth-layer portion or on a portion other than the fourth-layer antenna mounting portion on a four-layer board, An antenna element is mounted on the first-layer antenna mounting portion, and the first-layer antenna mounting portion other than the antenna feeding point is entirely grounded, the second layer is entirely grounded, and the third layer is grounding, power supply, and signal lines. The ASK modulation / demodulation wireless device according to claim 1, wherein the ASK modem is a surface. 5. A filter having a function of removing unnecessary components outside a band from a reception signal received from the transmission / reception antenna or a transmission signal transmitted from the transmission / reception antenna, wherein the ground plane is a two-layer ground plane or a three-layer ground plane. 2. The ASK modulation / demodulation radio according to claim 1, wherein the ASK modulation / demodulation radio is constituted by a two-wavelength stripline resonance type filter and arranged in a region corresponding to a fourth-layer antenna mounting portion. 6. The antenna element is mounted on the antenna mounting part such that an axis extending in a direction perpendicular to the component mounting part from the antenna element feeding point is a symmetric axis of the antenna mounting part. A described in item 1
SK modem radio. 7. The entire component mounting surface other than the antenna mounting portion on the antenna mounting surface side and the entire component mounting surface on the back surface when the antenna mounting surface is the front surface are shielded and mounted on the same surface as the synthesizer circuit. 2. A according to claim 1, further comprising a shield structure for shutting off another circuit block.
SK modem radio. 8. A substrate having a four-layer structure, wherein the first layer is an antenna element mounting surface and the entire area other than the antenna feed point is ground, and the second layer is a ground plane and a plane for routing power and signal lines. 2. The ASK modulation / demodulation wireless device according to claim 1, wherein the first layer is a ground plane, and the fourth layer is a component mounting surface excluding an antenna element. 9. The ASK modulation / demodulation radio according to claim 8, wherein said antenna element is disposed on a central axis of one layer. 10. The ASK according to claim 8, wherein the ASK has a shield structure for shielding the entire component mounting surface of the fourth layer and for shutting off the synthesizer circuit from other circuit blocks.
Modem radio.