JP2003304181A - Antenna switching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive antenna switching device which is excellent in performance without having to provide a distributor. <P>SOLUTION: This antenna switching device 21 provided with antennas 6a to 6d and devices 27a to 27c to be connected to the antennas and used in a reception system adopting a diversity method is provided with a selection switch 22 for selecting any of antenna signals from the antennas 6a to 6d and inputting the selected antenna signal, an output switch group 24 for outputting the antenna signal selected by the selection switch 22 to any of the devices 27a to 27c, a connection device switching circuit 25 for outputting the antenna signal to one of the devices by controlling the output switch group 24, and a decoder driver 25 for switching the antenna signal to be selected by the selection switch 22 by controlling the selection switch 22 on the basis of an instruction from the device. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna switching device, and more particularly to an antenna switching device including a plurality of antennas and devices to be connected to an antenna and used in a receiving system adopting a diversity system.

[0002]

2. Description of the Related Art Conventionally, an FM radio receiver is mounted on a vehicle so that a user can enjoy driving while listening to an FM radio broadcast. by the way,
When trying to receive an FM radio broadcast in a moving vehicle, fading (a phenomenon in which the electric field drops due to the temporal change of the medium) may interfere with good quality communication.

In order to suppress the deterioration of communication due to this fading, usually, a plurality of antennas are installed in the vehicle by changing the direction and place, and the reception level becomes a certain level or less during reception by a certain antenna (or multi-channel). When the reception situation deteriorates due to a path or the like), a diversity system is adopted, such as switching to another antenna for reception, or selecting and receiving the antenna with the better reception status.

Further, in recent years, in order to realize a more comfortable drive, a vehicle is often equipped with a television receiver so that a television broadcast can be watched, and the television receiver often adopts a diversity system. Has been done.
FIG. 7 is a block diagram schematically showing a receiving system including a plurality of antennas and a plurality of antenna connection target devices (for example, an FM radio receiver and a television receiver) and adopting a diversity system.

Reference numeral 1 in the figure denotes an antenna switching device,
The antenna switching device 1 includes distributors 2a to 2d for evenly distributing the antenna signals from the antennas 6a to 6d into two.
And selection switches 3 and 13 for selecting one of the antenna signals from the antennas 6a to 6d, amplifiers 4 and 14 for amplifying the antenna signal selected by the selection switches 3 and 13, and an antenna. 2-bit signal (00,0) sent from the connection target device 7,17
1, 10, 11), a decoder driver 5, which transmits a signal from one output terminal (terminal corresponding to each switch terminal 3a to 3d, 13a to 13d) corresponding to the combination of the received 2-bit signals, And 15 are included.

For example, when the decoder driver 5 receives the signal "00", the terminal 5 corresponding to the switch terminal 3a.
The signal (high level signal) is transmitted from a and “01” is sent.
When the signal of "10" is received, the signal is transmitted from the terminal 5b corresponding to the switch terminal 3b, and when the signals of "10" and "11" are received, the signals are transmitted from the terminals 5c and 5d corresponding to the switch terminals 3c and 3d, respectively. It is like this.

[0007]

By the way, in the receiving system shown in FIG. 7, the antennas 6a to 6d are shared by a plurality of antenna connection target devices 7 and 17, and the antenna connection target devices 7 and 17 are used depending on their convenience. , Antenna 6a
It is necessary to provide the distributors 2a to 2d to evenly distribute the antenna signal to the two antennas, because the switching is performed from 6d to 6d.

However, when the antenna signal is distributed, a distribution loss occurs and the noise figure of the entire receiving system deteriorates, so that there is a problem that the receiving sensitivity is lowered. Further, in order to compensate for this distribution loss, it is necessary to provide the amplifiers 4 and 14, which causes a problem of cost increase.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an antenna switching device which does not require a distributor and is inexpensive and excellent in performance.

[0010]

Means for Solving the Problems and Effects Thereof In order to achieve the above object, an antenna switching device (1) according to the present invention.
Is an antenna switching device that includes a plurality of antennas and a plurality of antenna connection target devices and is used in a reception system adopting a diversity system, and selects any one of the antenna signals from the plurality of antennas. And a first output means for outputting the antenna signal selected by the first input selection means to any one of the plurality of antenna connection target devices. A first device determining means for determining an antenna connection target device which should output the antenna signal; and controlling the first output device based on the determination by the first device determining means, From the antenna connection target device, a first output control unit that outputs the antenna signal to the antenna connection target device determined by the device determination unit Based on the instruction, by controlling the first input selection means is characterized by comprising a first input control means for switching the antenna signal selected by the input selection means of the first.

According to the antenna switching device (1), the antenna signal selected by the first input selecting means is output to any one of the plurality of antenna connection target devices. That is, since the antenna selected by the first input selection unit is not output to two or more different antenna connection target devices during the same period, it is not necessary to provide a distributor to distribute the antenna signal. Absent. Therefore, since distribution loss does not occur, it is not necessary to provide an amplifier, the noise figure is not deteriorated, and the reception sensitivity can be prevented from being lowered. Therefore, an inexpensive and excellent antenna switching device can be provided. Can be realized.

Further, since the antenna signal selected by the first input selecting means can be switched based on the instruction from the antenna connection target device, the convenience of the antenna connection target device (for example, reception strength Decrease)
The antennas can be freely switched by using the (diversity method).

Further, the antenna switching device (2) according to the present invention is the second device for selecting and inputting any one of the antenna signals from the plurality of antennas in the antenna switching device (1). Input selection means, and second output means for outputting the antenna signal selected by the second input selection means to a predetermined antenna connection target device among the plurality of antenna connection target devices.
When the first device determination unit determines that the predetermined antenna connection target device is a device to output the antenna signal, the second output unit is controlled to control the predetermined antenna connection target device. A second output control means for outputting the antenna signal and a second input selection means by controlling the second input selection means based on an instruction from the antenna connection target device. Second input control means for switching the selected antenna signal, and the antenna signal selected by the first input selection means and the antenna signal selected by the second input selection means are exclusive. It is characterized by being configured as follows.

Some devices to be connected to an antenna have two or more input terminals for inputting antenna signals, and input antenna signals from two or more different antennas in the same period.

According to the antenna switching device (2), when the predetermined antenna connection target device is determined as the antenna connection target device which should output the antenna signal,
The antenna signal selected by the first input selection means and the antenna signal selected by the second input selection means are output to the predetermined antenna connection target device. Therefore, the antenna signals from two different antennas can be output to the predetermined antenna connection target device in the same period. Further, since the antenna signal selected by the first input selection means and the antenna signal selected by the second input selection means are configured to be exclusive, a distributor should be provided. It is not necessary to distribute each antenna signal.

The antenna switching device (3) according to the present invention is the second antenna switching device (1) for selecting and inputting any one of the antenna signals from the plurality of antennas. The input selection means, a third output means for outputting the antenna signal selected by the second input selection means to any one of predetermined two or more antenna connection target devices; and the first output means. When the device determining unit determines that any one of the predetermined two or more antenna connection target devices is a device to output the antenna signal, the device determining unit controls the third output unit to determine the device. The third output control means for outputting the antenna signal to the antenna connection target device determined by the means, and the second output control means based on an instruction from the antenna connection target device. Second input control means for switching the antenna signal selected by the second input selection means by controlling the force selection means, and an antenna signal selected by the first input selection means, The antenna signal selected by the second input selecting means is configured to be exclusive.

Some antenna connection target devices have two or more input terminals for inputting antenna signals and input antenna signals from two or more different antennas in the same period.

According to the antenna switching device (3), when any one of the predetermined two or more antenna connection target devices is determined as the antenna connection target device which should output the antenna signal, the first The antenna signal selected by the first input selection means and the antenna signal selected by the second input selection means are output to the determined antenna connection target device. Therefore, antenna signals from two different antennas can be output to the antenna connection target device in the same period.

Also, according to the antenna switching device (3), unlike the antenna switching device (2), an antenna connection target device that requests input of antenna signals from two different antennas in the same period is provided. Two or more can be connected. Further, since the antenna signal selected by the first input selection means and the antenna signal selected by the second input selection means are configured to be exclusive, a distributor should be provided. It is not necessary to distribute each antenna signal.

The antenna switching device (4) according to the present invention is a phase conversion device for converting the phase of the antenna signal selected by the second input selecting means in the antenna switching device (2) or (3). It is characterized by having means.

By the way, when the direction of the antenna provided at the front right of the vehicle and the direction of the antenna provided at the rear right of the vehicle are different, the antenna signal from the antenna provided at the front right and the antenna signal from the antenna provided at the rear right. As a matter of course, since the phases are different, it is impossible to combine both antenna signals as they are.

According to the antenna switching device (4), since the phase of the antenna signal selected by the second input selecting means can be converted, the antenna signal selected by the second input selecting means. Can be the same as the phase of the antenna signal selected by the first input selection means. Therefore, it is possible to combine antenna signals from different antennas, and it is possible to output a highly reliable antenna signal to the antenna connection target device.

The antenna switching device (5) according to the present invention comprises a plurality of antennas and an antenna connection target device having a main input terminal / sub input terminal for inputting an antenna signal, and a diversity system is used. An antenna switching device used for the adopted receiving system, comprising: a third input selecting means for selecting and inputting any one of the antenna signals from the plurality of antennas; and the third input selecting means. The antenna signal selected by
Fourth output means for outputting to any of the main input terminal / sub input terminal of the antenna connection target device, and based on an instruction from the antenna connection target device,
By controlling the third input selection means, the third input control means for switching the antenna signal selected by the third input selection means, and the third input control means based on an instruction from the antenna connection target device. By controlling the output means of No. 4 to output the antenna signal selected by the third input selection means to any one of the main input terminal / sub input terminal, and the plurality of antennas. Fourth input selecting means for selecting and inputting any one of the antenna signals of the above, and the antenna signal selected by the fourth input selecting means, the main input terminal / sub of the antenna connection target device. The fifth output means for outputting to any one of the input terminals and the fourth output means based on an instruction from the antenna connection target device.
Controlling the input selecting means of the fourth input selecting means to switch the antenna signal selected by the fourth input selecting means, and the fifth output based on an instruction from the antenna connection target device. A fifth output control means for controlling the means to output the antenna signal selected by the fourth input selection means to any one of the main input terminal / sub input terminal, and the third input An antenna signal selected by the selection means,
The antenna signal selected by the fourth input selection means is configured to be exclusive, and further, the fourth
The output destination of the antenna signal output from the output means and the output destination of the antenna signal output from the fifth output means are configured to be exclusive.

According to the antenna switching device (5), the antenna signal selected by the third input selecting means is output to any of the main input terminal / sub input terminal of the antenna connection target device. For outputting the antenna signal selected by the fourth input selection means to any one of a main input terminal / sub input terminal of the antenna connection target device. 5, the output destination of the antenna signal output from the fourth output means and the output destination of the antenna signal output from the fifth output means are exclusive. Is configured.

That is, when the antenna signal selected by the third input selecting means is output to the main input terminal of the antenna connection target device, the fourth signal is output.
When the antenna signal selected by the input selecting means is output to the sub input terminal, conversely, when the antenna signal selected by the third input selecting means is output to the sub input terminal, The antenna signal selected by the fourth input selection means is output to the main input terminal.

Since the antenna signal selected by the third input selecting means and the antenna signal selected by the fourth input selecting means are configured to be exclusive, the antenna connection is established. Antenna signals from different antennas can be output to the main input terminal / sub input terminal of the target device.

The output destination of each antenna signal selected by the third input selecting means / the fourth input selecting means is switched based on an instruction from the antenna connection target device. Therefore, the antennas can be freely switched depending on the convenience of the device to which the antenna is connected (for example, the reception intensity of the main input terminal is lowered).

For example, when the reception intensity of the antenna signal input from the sub input terminal exceeds the reception intensity of the antenna signal input from the main input terminal, the antenna connection target device gives an instruction to switch the antenna. If so, the antenna signal output to the main input terminal and the antenna signal output to the sub input terminal can be switched.

Further, as described above, the antenna signal selected by the third input selecting means and the antenna signal selected by the fourth input selecting means are configured to be exclusive. Therefore, it is not necessary to provide a distributor to distribute the antenna signal. Therefore, since distribution loss does not occur, it is not necessary to provide an amplifier, the noise figure is not deteriorated, and the reception sensitivity can be prevented from being lowered. Therefore, an inexpensive and excellent antenna switching device can be provided. Can be realized.

Further, since the antenna signal selected by the third input selecting means / the fourth input selecting means can be switched based on the instruction from the antenna connection target device, the antenna connection target device It is possible to freely switch the antenna depending on the circumstances (for example, reduction of the reception intensity). Therefore, for example, by switching only the antenna connected to the sub input terminal without switching the antenna connected to the main input terminal, a diversity method combining the scanning type and the selection type can be realized. Can be realized.

In the antenna switching device (6) according to the present invention, in the antenna switching device (5), the antenna connection target among the third input selecting means and the fourth input selecting means. The antenna of the input selection means connected to the main input terminal of the device is not switched, while the antenna of the input selection means connected to the sub input terminal of the device to be connected to the antenna is not switched. It is characterized by being configured to be opened.

According to the antenna switching device (6), the antenna connected to the main input terminal is not switched, but only the antenna connected to the sub input terminal is switched. The scanning diversity method can be realized without receiving detailed instructions from the antenna connection target device. Therefore, the configuration of the antenna switching device can be simplified.

The antenna switching device (7) according to the present invention is the antenna switching device (5) or (6), wherein the fourth output means is selected by the third input selecting means. A device for outputting a signal to any one of the antenna connection target device and one or more antenna connection target devices other than the antenna connection target device. Second device determining means for determining, and the antenna connection target device determined by the second device determining means by controlling the fourth output means based on the determination by the second device determining means. And a sixth output control means for outputting the antenna signal.

According to the antenna switching device (7), the antenna signal selected by the third input selecting means is output to any one of the plurality of antenna connection target devices. Therefore, the antenna switching device can also be adopted in a reception system including a plurality of antenna connection target devices.

The antenna switching device (8) according to the present invention is the antenna switching device (8) according to any one of the antenna switching devices (1) to (7), wherein the antenna signal line connecting the plurality of antennas to the antenna connection target device is A first passage means through which the antenna signal can pass is provided, and the passage of the antenna signal is blocked between the first passage means and the device to be connected to the antenna while transmitting from the device to be connected to the antenna. It is characterized in that the first blocking means for passing the incoming signal are connected in series.

According to the antenna switching device (8), an antenna signal line (that is, a line for transmitting an antenna signal) that connects a plurality of antennas and the antenna connection target device.
Is provided with the first passing means (for example, a filter that passes a high frequency of 30 MHz or higher) through which the antenna signal can pass, and between the first passing means and the antenna connection target device, The first blocking unit (for example, 1) that blocks the signal transmitted from the antenna connection target device while blocking the antenna signal from passing therethrough.
Filters that pass low frequencies of 00 kHz or less) are connected in series.

That is, if the signal is transmitted using a low-frequency carrier, the signal can be transmitted from the device to be connected to the antenna to a predetermined location using the antenna signal line as a medium. . Therefore, it is not necessary to provide a separate signal line only for inputting a signal from the antenna connection target device, so that the device can be simplified.

The antenna switching device (9) according to the present invention also includes a first antenna group including a first antenna and a second antenna, a third antenna and a fourth antenna. A second antenna group composed of
A first input terminal for inputting an antenna signal and a second
An antenna switching device for use in a receiving system adopting a diversity system, comprising: an antenna connection target device having two input terminals for transmitting signals showing two different significant states, the first antenna group And a fifth input selection means for selecting and inputting an antenna signal from the first antenna or an antenna signal from the second antenna, which constitutes the second antenna group. Antenna signal from the third antenna, or the fourth signal
A sixth input selecting means for selecting and inputting an antenna signal from the antenna of the first antenna, and connecting the first antenna group and the first input terminal of the antenna connection target device to the first input terminal. The antenna signal line is provided with a second passage means through which the antenna signal can pass, and prevents the antenna signal from passing between the second passage means and the antenna connection target device. A second blocking unit that allows a signal transmitted from the antenna connection target device to pass therethrough is connected in series, and the fifth input selection unit, based on the signal transmitted from the antenna connection target device,
The antenna is switched, while the second
The second antenna signal line connecting the group of antennas and the second input terminal of the device to be connected to the antenna is also provided with a third passage means through which the antenna signal can pass, and the third passage means. A third blocking means for blocking the passage of the antenna signal while allowing the signal transmitted from the antenna connection target device to pass therethrough, and the sixth input selection circuit. The means switches the antenna based on a signal transmitted from the antenna connection target device.

By the way, in VHF and UHF of television broadcasting, since UHF has a higher frequency band than VHF, there are cases in which two antennas having different frequency bands used are arranged in a vehicle. When receiving the UHF radio wave, the antennas a and b may be used, and when receiving the VHF radio wave, the antennas c and d having different use frequency bands from the antennas a and b may be used.
Therefore, in such a case, the antenna a and the antenna b are
Since and form a pair, and the antenna c and the antenna d form a pair, it may be necessary to switch the antenna to be used for each pair.

According to the antenna switching device (9), the antenna signal selected by the fifth input selecting means is output to the first input terminal of the antenna connection target device. Further, since the antenna signal selected by the fifth input selection means is switched based on the signal (for example, high level or low level) output from the antenna connection target device, the convenience of the antenna connection target device is increased. Thus, the antennas of the first antenna group can be freely switched.

The antenna signal selected by the sixth input selection means is output to the second input terminal of the antenna connection target device. In addition, the signal output from the device to which the antenna is connected (for example, High level, Lo
Since the antenna signal selected by the sixth input selection means is switched based on the w level), the antennas of the second antenna group can be freely switched depending on the convenience of the device to which the antenna is connected. it can.

For example, a high level signal (for example, 12V) is output from the first input terminal of the antenna connection target device.
Signal voltage) is output, and low from the second input terminal
When a level signal (for example, a signal voltage of 0V) is output, the antenna signal from the first antenna of the first antenna group is output to the first input terminal, and the second antenna group is output. The antenna signal from the third antenna can be output to the second input terminal.

On the contrary, a low level signal (for example, a signal voltage of 0V) is output from the first input terminal and a high level signal (for example, 12V) is output from the second input terminal.
V signal voltage), the antenna signal from the second antenna of the first antenna group is output to the first input terminal and the fourth signal of the second antenna group is output.
The antenna signal from the antenna can be output to the second input terminal. Therefore, the first
The antenna and the third antenna are paired, the second antenna and the fourth antenna are paired, and the antenna to be used can be easily switched for each pair.

Further, since the signal can be transmitted from the antenna connection target device through the antenna signal line as a medium, another signal line only for inputting the signal from the antenna connection target device. Since it is not necessary to provide, it is possible to simplify the device.

Further, the antenna switching device according to the present invention (1
0) is connected to the first antenna signal line through the first blocking means in the antenna switching device (9), and allows a signal passing through the first blocking means to flow in only one direction. A second rectifying means, which is connected to the second antenna signal line through the second blocking means, and which allows a signal passing through the second blocking means to flow a current in only one direction.
And a rectifying means of.

According to the antenna switching device (10),
Since the first rectifying means which is connected to the first antenna signal line through the first blocking means and flows the signal passing through the first blocking means in only one direction is provided, When a high level (for example, a signal voltage of 12V) is output from the first input terminal, the signal voltage is set to the first level.
Can be flowed from the rectifying means.

Further, there is provided a second rectifying means which is connected to the second antenna signal line through the second blocking means and which allows a signal passing through the second blocking means to flow in only one direction. Therefore, when a high level (for example, a signal voltage of 12V) is output from the second input terminal, the signal voltage can be flown from the second rectifying means.

That is, from one of the first input terminal and the second input terminal of the antenna connection target device, Hi
As long as a gh level signal is output, a signal voltage of 12 V can be supplied from the first rectifying means or the second rectifying means. Further, this 12V signal voltage can be used as a power supply voltage in the antenna switching device. Therefore, since it is not necessary to provide another power supply circuit device in the antenna switching device, the device can be simplified.

[0049]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an antenna switching device according to the present invention will be described below with reference to the drawings. Figure 1
FIG. 3 is a block diagram schematically showing a main part of a reception system that employs the antenna switching device according to the embodiment (1).
The case where the receiving system is adopted in a vehicle will be described here.

In the figure, reference numeral 21 denotes an antenna switching device. The antenna switching device 21 has a selection switch 22 for selecting any one of the antenna signals from the antennas 6a to 6d and a selection switch 22 for switching. Of the antenna signal selected by the decoder driver 23 and the selection switch 22 of the plurality of antenna connection target devices 2
7a to 27c, an output switch group 24 for outputting to any one of 7a to 27c, and a connected device switching circuit 25 for switching each output switch 24a to 24c constituting the output switch group 24.

Each of the antennas 6a to 6d is installed at a predetermined location on the vehicle in a predetermined direction, and each of the antennas 6a to 6d is provided on the input terminal 2 of the selection switch 22.
2a to 22d, and the output terminal 22e of the selection switch 22 is connected to the input side of the output switch group 24.

The output side of the output switch group 24 is 30 MH
The antenna connection target devices 27a to 27c are passed through HPFs (high-pass filters) 26a to 26c through which an antenna signal having a high frequency equal to or higher than z (that is, an antenna signal transmitted from a broadcasting station of FM radio or television) can pass. Connected with. Note that the HPFs 26a to 26c may be capacitors having a small capacity.

The connected device switching circuit 25 takes in the output power supply voltage of the power supply circuit (not shown) equipped in each of the antenna connection target devices 27a to 27c and monitors the change of the rising edge, and outputs the output of the power supply circuit. When the rising of the power supply voltage is detected, the control signal is output so that the antenna signal is output to the antenna connection target devices 27a to 27c in which the output power supply voltage of the power supply circuit has risen.
It is designed to output to.

If the output power supply voltage of the power supply circuit of another antenna connection target device rises while the power supply circuit of one antenna connection target device has already risen, the antenna connection target device that has risen later is connected to the antenna connection target device. The control signal is output to the output switch group 24 so that the antenna signal is output.

When the decoder driver 23 receives the 2-bit signal (00, 01, 10, 11) sent from the antenna connection target devices 27a to 27c, the received 2
One output terminal 2 corresponding to the combination of bit signals
3a to 23d (each input terminal 22a to the selection switch 22)
The signal is transmitted from a terminal corresponding to 22d).

For example, the decoder driver 23 is "00".
When the signal of is received, the input terminal 22 of the selection switch 22
When the control signal (high-level signal) is transmitted from the output terminal 23a corresponding to a and the signal of "01" is received, the output terminal 23 corresponding to the input terminal 22b of the selection switch 22 is transmitted.
When the control signal is transmitted from b and the respective signals of "10" and "11" are received, the control signal is transmitted from the output terminals 23c and 23d corresponding to the input terminals 22c and 22d, respectively. As a result, the antennas can be freely switched based on the instructions from the antenna connection target devices 27a to 27c.

Next, an example of the operation of the antenna switching device according to the embodiment (1) will be described. When the user turns on the power switch of the analog television in order to watch the analog television (antenna connection target device 27a), the power supply circuit of the antenna connection target device 27a supplies power to each unit in the device.

The connected device switching circuit 25 monitors the rising of the output power supply voltage of the power supply circuit. When the output power supply voltage of the power supply circuit rises, the antenna connection target device in which the output power supply voltage of the power supply circuit rises 27a
The output switch 24 of the output switch group 24 outputs the control signal so that the antenna signal is output to the (analog TV).
Output to a. At this time, the output terminal 22e of the selection switch 22 is assumed to be connected to the input terminal 22a (antenna 6a).

The antenna connection target device 27a inputs the antenna signal from the antenna 6a at the start-up, but when the reception intensity of this antenna signal becomes a predetermined value or less, a 2-bit signal ( For example, "01") is transmitted.

When the decoder driver 23 receives the 2-bit signal from the antenna connection target device 27a, it outputs a control signal (high level signal) from a predetermined output terminal (for example, the output terminal 23b) based on the received signal. Send.

The selection switch 22 is the decoder driver 2
When receiving the control signal from 3, the output terminal 22e and the input terminal 22b (antenna 6b) are connected. Thereby, the antenna signal output to the antenna connection target device 27a is changed from the antenna signal of the antenna 6a to the antenna 6
Switch to the antenna signal of b.

According to the antenna switching device of the above embodiment (1), the antenna signal selected by the selection switch 22 is output to any of the antenna connection target devices 27a to 27c. There is. That is, since the antenna selected by the selection switch 22 is not output to two or more different antenna connection target devices during the same period, it is not necessary to provide a distributor to distribute the antenna signal.

Therefore, since no distribution loss occurs, it is not necessary to provide an amplifier, the noise figure is not deteriorated, and the reception sensitivity can be prevented from lowering. Therefore, the antenna is inexpensive and excellent in performance. A switching device can be realized.

The antenna connection target devices 27a to 27 are also provided.
Since the antenna signal selected by the selection switch 22 can be switched based on the instruction from c, the antennas can be freely switched depending on the convenience of the antenna connection target devices 27a to 27c (for example, reduction in reception strength). It is possible (realization of diversity method).

FIG. 2 is a block diagram schematically showing a main part of a receiving system that employs the antenna switching device according to the embodiment (2). However, the same components as those of the antenna switching device shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted here.

Reference numeral 31 in the drawing denotes an antenna switching device. The antenna switching device 31 includes selection switches 22 and 32 for selecting one of the antenna signals from the antennas 6a to 6d, and a selection switch 22 ,. Decoder driver 33 for switching 32 and selection switch 2
The output switch group 24 for outputting the antenna signal selected by 2 to any one of the plurality of antenna connection target devices 27a, 27b, 37, and the selection switch 32.
The output switch 34 for outputting the antenna signal selected by the antenna connection target device 37, and the output switches 24a to 24c constituting the output switch group 24,
And a connected device switching circuit 35 for switching ON / OFF of the output switch 34.

Each of the antennas 6a to 6d is installed at a predetermined location on the vehicle in a predetermined direction.
a to 6d are input terminals 2 of the selection switches 22 and 32, respectively.
2a to 22d and 32a to 32d, the output terminal 22e of the selection switch 22 is connected to the input side of the output switch group 24, and the output terminal 32e of the selection switch 32.
Is connected to the input side of the output switch 34.

The output side of the output switch group 24 is 30 MH
The antenna connection target devices 27a and 27b are passed through HPFs (high-pass filters) 26a to 26c through which an antenna signal having a high frequency equal to or higher than z (that is, an antenna signal transmitted from a broadcasting station of FM radio or television) can pass. , 37. Also on the output side of the output switch 34, the antenna connection target device 3 is connected via the HPF 36 through which an antenna signal of a high frequency of 30 MHz or more can pass.
It is connected to 7. Note that the HPF 36 may be a small-capacity capacitor or the like.

The connected device switching circuit 35 takes in the output power supply voltage of a power supply circuit (not shown) equipped in each antenna connection target device 27a, 27b, 37 and monitors the change in the rising edge. When the rise of the output power supply voltage of the device is detected, the antenna connection target devices 27a, 27b, 3 in which the output power supply voltage of the power supply circuit rises
The control signal is output to the output switch group 24 and the output switch 34 so that the antenna signal is output to the output switch 7.

If the output power supply voltage of the power supply circuit of another antenna connection target device rises while the power supply circuit of one antenna connection target device has already risen, the antenna connection target device that has risen afterwards The control signal is output to the output switch group 24 and the output switch 34 so that the antenna signal is output.

When the decoder driver 33 receives the 2-bit signals (00, 01, 10, 11) sent from the antenna connection target devices 27a, 27b, 37, it corresponds to the combination of the received 2-bit signals. One output terminal 33a _{1 to} 33d ₁ , 33a _{2 to} 33d ₂ (each input terminal 22a to 22d, 32a of the selection switch 22, 32)
The signal is transmitted from the output terminal corresponding to 32d.

Further, the decoder driver 33 includes the antenna selected by the selection switch 22 and the selection switch 3
So that the antenna selected by 2 is exclusive,
It is adapted to transmit the signal.

For example, the decoder driver 33 is "00".
When the signal of is received, the input terminal 22 of the selection switch 22
The control signal (high-level signal) is transmitted from the output terminal 33a ₁ corresponding to a, while the control signal (Hi level is output from the output terminal 33b ₂ corresponding to the input terminal 32b of the selection switch 32).
gh level signal) and the signal of "11" is received, the control signal is transmitted from the output terminal 33d ₁ corresponding to the input terminal 22d of the selection switch 22, while the input terminal 32a of the selection switch 32 is supported. The control signal is transmitted from the output terminal 33a _{2 that} operates. This allows
The antennas can be freely switched based on the instructions from the antenna connection target devices 27a, 27b, and 37.

Next, an example of the operation of the antenna switching device according to the embodiment (2) will be described. When the user turns on the power switch of the analog television in order to watch the analog television (antenna connection target device 27a), the power supply circuit of the antenna connection target device 27a supplies power to each unit in the device.

The connected device switching circuit 35 monitors the rising of the output power supply voltage of the power supply circuit. When the output power supply voltage of the power supply circuit rises, the antenna connection target device in which the output power supply voltage of the power supply circuit rises 27a
Outputs a control signal (high-level signal) so that the antenna signal is output to (analog TV) switch group 2
4 (output switch 24a).

At this time, the output switch 34 is turned off.
In addition, the output terminal 22e of the selection switch 22 is connected to the input terminal 22a (antenna 6a), and the output terminal 32e of the selection switch 32 is the input terminal 3
2b (antenna 6b) is connected.

The antenna connection target device 27a inputs the antenna signal from the antenna 6a at the start-up, but when the reception intensity of this antenna signal falls below a predetermined value, a 2-bit signal ( For example, "01") is transmitted.

When the decoder driver 33 receives a 2-bit signal from the antenna connection target device 27a, it outputs a control signal from a predetermined output terminal (for example, output terminal 33b ₁ or output terminal 33c ₂ ) based on the received signal. Send.

The selection switch 22 is the decoder driver 3
When receiving the control signal from 3, the output terminal 22e and the input terminal 22b (antenna 6b) are connected. Thereby, the antenna signal output to the antenna connection target device 27a is changed from the antenna signal of the antenna 6a to the antenna 6
Switch to the antenna signal of b. When the selection switch 32 receives the control signal from the decoder driver 33, the selection switch 32 outputs the output terminal 32e and the input terminal 32c (the antenna 6).
c) and are connected.

Next, when the power switch of the digital television is turned on in order to allow the user to watch the digital television (antenna connection target device 37), the power supply circuit of the antenna connection target device 37 turns on the power supply to each section in the device. Supplied.

The connected device switching circuit 35 monitors the rising of the output power supply voltage of the power supply circuit. When the output power supply voltage of the power supply circuit rises, the antenna connection target device in which the output power supply voltage of the power supply circuit rises So that the antenna signal can be output to 37 (digital television),
Outputs control signal (High level signal) Switch group 24
(Output switch 24c) and output switch 34.

At this time, the output terminal 22e of the selection switch 22 is connected to the input terminal 22b (antenna 6b), and the output terminal 32e of the selection switch 32 is the input terminal 3
2c (antenna 6c).

The device 37 to be connected to the antenna receives the antenna signals from the antennas 6b and 6c at the start-up, but when the reception strength of the antenna signals from the antennas 6b and 6c becomes a predetermined value or less, the decoder A 2-bit signal (for example, "10") is transmitted to the driver 33.

When the decoder driver 33 receives a 2-bit signal from the antenna connection target device 37, the decoder driver 33 determines a predetermined output terminal (for example, the output terminal 3) based on the received signal.
A control signal (high-level signal) is transmitted from 3c ₁ and the output terminal 33d ₂ .

The selection switch 22 is the decoder driver 3
When receiving the control signal from 3, the output terminal 22e and the input terminal 22c (antenna 6c) are connected, while the selection switch 32 connects the output terminal 32e and the input terminal 32d (antenna 6d). As a result, the antenna signal output to the antenna connection target device 37 is transmitted to the antenna 6
The antenna signals of the antennas 6c and 6d are switched from b and 6c.

According to the antenna switching device of the above embodiment (2), when the antenna connection target device 37 having two input terminals is determined as the antenna connection target device which should output the antenna signal, The antenna signal selected by the selection switch 22 and the antenna signal selected by the selection switch 32 are output to the antenna connection target device 37. Therefore, antenna signals from two different antennas can be output to the antenna connection target device 37 during the same period.

Further, since the antenna signal selected by the selection switch 22 and the antenna signal selected by the selection switch 32 are configured to be exclusive, a distributor is provided to each antenna. There is no need to distribute the signal.

In the antenna switching device according to the above embodiment (2), only the case where only one antenna connection target device 37 having two or more input terminals is connected will be described. Even when two or more connection target devices are connected, it can be realized in the same form as described above.

FIG. 3 is a block diagram schematically showing a main part of a receiving system that employs the antenna switching device according to the embodiment (3). However, the same components as those of the antenna switching device shown in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted here.

Reference numeral 41 in the drawing denotes an antenna switching device. The antenna switching device 41 includes selection switches 22 and 32 for selecting one of the antenna signals from the antennas 6a to 6d, and a selection switch 22 ,. Decoder driver 43 for switching 32 and selection switch 2
The output switch group 24 for outputting the antenna signal selected by 2 to any one of the plurality of antenna connection target devices 27a to 27c, and the antenna signal selected by the selection switch 32, the antenna connection target device 27.
The output switch 44 for outputting to a, the output switches 24a to 24c constituting the output switch group 24, and the connected device switching circuit 45 for switching ON / OFF of the output switch 44 are configured. . Also,
A phase shift 42 for converting the phase of the antenna signal is provided between the selection switch 32 and the output switch 44.

Each of the antennas 6a to 6d is installed at a predetermined location of the vehicle in a predetermined direction, and the antenna 6a
a to 6d are input terminals 2 of the selection switches 22 and 32, respectively.
2a to 22d and 32a to 32d, the output terminal 22e of the selection switch 22 is connected to the input side of the output switch group 24, and the output terminal 32e of the selection switch 32.
Is connected to the input side of the output switch 44.

The output side of the output switch group 24 is 30 MH
The antenna connection target devices 27a to 27c are passed through HPFs (high-pass filters) 26a to 26c through which an antenna signal having a high frequency equal to or higher than z (that is, an antenna signal transmitted from a broadcasting station of FM radio or television) can pass. Connected with. Further, also on the output side of the output switch 44, the antenna connection target device 27c is passed through the HPF 46 that can pass an antenna signal of high frequency of 30 MHz or more.
Connected with. The HPF 46 may be a small capacity capacitor or the like.

The connected device switching circuit 45 takes in the output power supply voltage of the power supply circuit (not shown) equipped in each of the antenna connection target devices 27a to 27c, and monitors the change of the rising edge, and outputs the output of the power supply circuit. When the rising of the power supply voltage is detected, a control signal is output so that the antenna signal is output to the antenna connection target devices 27a to 27c in which the output power supply voltage of the power supply circuit has risen.
4, output to the output switch 44.

If the output power supply voltage of the power supply circuit of another antenna connection target device rises while the power supply circuit of one antenna connection target device has already risen, the antenna connection target device that has started up later The control signal is output to the output switch group 24 and the output switch 44 so that the antenna signal is output.

When the decoder driver 43 receives the 2-bit signal (00, 01, 10, 11) sent from the antenna connection target devices 27a to 27c, it receives 2 signals.
One output terminal 4 corresponding to the combination of bit signals
3a _{1 to} 43d ₁ , 43a _{2 to} 43d ₂ (each input terminal 22a to 22d, 32a to 32 of the selection switch 22, 32)
The signal is transmitted from the output terminal corresponding to d).

Further, the decoder driver 43 includes the antenna selected by the selection switch 22 and the selection switch 3
So that the antenna selected by 2 is exclusive,
It is adapted to transmit the signal.

For example, the decoder driver 43 is "00".
When the signal of is received, the input terminal 22 of the selection switch 22
The control signal (high-level signal) is transmitted from the output terminal 43a ₁ corresponding to a, while the control signal (Hi level is output from the output terminal 43b ₂ corresponding to the input terminal 32b of the selection switch 32).
gh level signal) and receives the signal of "11", the control signal is transmitted from the output terminal 43d ₁ corresponding to the input terminal 22d of the selection switch 22 and the input terminal 32a of the selection switch 32 is transmitted. A control signal is transmitted from the output terminal 43a _{2 that} operates. This allows
The antennas can be freely switched based on instructions from the antenna connection target devices 27a to 27c.

Next, an example of the operation of the antenna switching device according to the embodiment (3) will be described. The power switch of the digital radio is turned on so that the user can listen to the digital radio (antenna connection target device 27b).
Then, the power supply circuit of the antenna connection target device 27b supplies power to each unit in the device.

The connected device switching circuit 45 monitors the rising of the output power supply voltage of the power supply circuit. When the output power supply voltage of the power supply circuit rises, the antenna connection target device in which the output power supply voltage of the power supply circuit rises 27b
Outputs a control signal (high-level signal) so that the antenna signal is output to the (digital radio) switch group 2
4 (output switch 24b).

At this time, the output switch 44 is turned off.
In addition, the output terminal 22e of the selection switch 22 is connected to the input terminal 22a (antenna 6a), and the output terminal 32e of the selection switch 32 is the input terminal 3
2b (antenna 6b) is connected.

The antenna connection target device 27b inputs the antenna signal from the antenna 6a at the start-up, but when the reception intensity of this antenna signal becomes a predetermined value or less, a 2-bit signal ( For example, "01") is transmitted.

When the decoder driver 43 receives the 2-bit signal from the antenna connection target device 27b, the decoder driver 43 outputs a control signal (from the output terminal 43b ₁ or the output terminal 43c ₂ ) based on the received signal. High level signal) is transmitted.

The selection switch 22 is the decoder driver 4
When receiving the control signal from 3, the output terminal 22e and the input terminal 22b (antenna 6b) are connected. As a result, the antenna signal output to the antenna connection target device 27b is changed from the antenna signal of the antenna 6a to the antenna 6
Switch to the antenna signal of b. When the selection switch 32 receives the control signal from the decoder driver 43, the selection switch 32 outputs the output terminal 32e and the input terminal 32c (antenna 6).
c) and are connected.

Next, when the power switch of the analog television is turned on for the user to watch the analog television (antenna connection target device 27a), the power supply circuit of the antenna connection target device 27a supplies power to each part in the device. Supplied.

The connected device switching circuit 45 monitors the rising of the output power supply voltage of the power supply circuit, and when the output power supply voltage of the power supply circuit rises, the antenna connection target device in which the output power supply voltage of the power supply circuit rises. 27a
Outputs a control signal (high-level signal) so that the antenna signal is output to (analog TV) switch group 2
4 (output switch 24a) and the output switch 44.

At this time, the output terminal 22e of the selection switch 22 is connected to the input terminal 22b (antenna 6b), and the output terminal 32e of the selection switch 32 is the input terminal 3
2c (antenna 6c).

Thus, the antenna connection target device 27a
A composite of the antenna signal from the antenna 6b and the antenna signal from the antenna 6c, which has been phase-converted by the phase shift 42, is input to the.

According to the antenna switching device of the above embodiment (3), since the phase of the antenna signal selected by the selection switch 32 can be converted, the phase of the antenna signal selected by the selection switch 32 can be changed. , The phase of the antenna signal selected by the selection switch 22 can be made the same. Therefore, it is possible to combine antenna signals from different antennas, and it is possible to output a highly reliable antenna signal to the antenna connection target device 27a.

FIG. 4 is a block diagram schematically showing a main part of a receiving system that employs the antenna switching device according to the embodiment (4). However, the same components as those of the antenna switching device shown in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted here.

In the figure, reference numeral 51 denotes an antenna switching device. The antenna switching device 51 includes selection switches 22 and 32 for selecting one of the antenna signals from the antennas 6a to 6d, and a selection switch 22 ,. The decoder drivers 53 and 63 for switching 32 and the antenna signal selected by the selection switch 22 are supplied to either the main input terminal M / sub input terminal S of the antenna connection target device 27a and the antenna connection target device 57. Output switch group 54 for outputting to the selection switch 32
The output switch group 64 for outputting the antenna signal selected by the above to any one of the main input terminal M / sub input terminal S of the antenna connection target device 57, and each output switch 54a forming the output switch group 54. ~ 54
c, each output switch 64b of the output switch group 64,
And a connected device switching device 55 (having a connected device switching circuit 55a) for switching 64c.

Each of the antennas 6a to 6d is installed in a predetermined location of the vehicle in a predetermined direction, and the antenna 6a
a to 6d are input terminals 2 of the selection switches 22 and 32, respectively.
2a to 22d and 32a to 32d, the output terminal 22e of the selection switch 22 is connected to the input side of the output switch group 54, and the output terminal 32e of the selection switch 32.
Are connected to the input side of the output switch group 64.

The output side of the output switch group 54 is 30 MH
The antenna connection target devices 27a and 57 are passed through HPFs (high-pass filters) 56a to 56c through which an antenna signal having a high frequency equal to or higher than z (that is, an antenna signal transmitted from a broadcasting station of FM radio or television) can pass. Connected with. The output side of the output switch group 64 is also connected to the antenna connection target device 57 via HPFs 66b and 66c through which antenna signals having a high frequency of 30 MHz or higher can pass. In addition, HPF56a ~ 56
Examples of c, 66b, and 66c include small-capacity capacitors.

The connected device switching circuit 55a which constitutes the connected device switching device 55 includes the devices 27a, 5a connected to the respective antennas.
The output power supply voltage of the power supply circuit (not shown) equipped in 7 is input and the change of the rising edge is monitored. When the rising edge of the output power supply voltage of the power supply circuit is detected, the output power supply voltage of the power supply circuit changes. The control signal is output to the output switch group 54 group and the output switch 64 group so that the antenna signal is output to the antenna connection target devices 27a and 57 that have risen.

For example, when the output power supply voltage of the power supply circuit of the antenna connection target device 27a rises, the connection device switching circuit 55a causes the output switch group 54 (output switch) to output an antenna signal to the antenna connection target device 27a. 54a) and outputs a control signal (High level signal) to the decoder drivers 53 and 63.
Outputs gh-level signal), while rises the output power supply voltage of the power supply circuit of the antenna connected device 57, connected device switching circuit 55a is, the AND circuit 55b ₁ ~55b ₄
A control signal (high-level signal) is output to all of them. Note that the decoder drivers 53 and 6
The sending of the control signal to the 3 will be described in detail later,
The decoder drivers 53 and 63 have selection switches 22 and 32.
This is for permitting the switching of.

At this time, the antenna switching device 51
When only the main input terminal of the antenna connection target device 57 is connected, the connection device switching circuit 55a operates as AN.
When the control signal is output only to the D circuits 55b ₁ and 55b ₂ and conversely, only the sub-input terminal is connected, the connected device switching circuit 55a is the AND circuit 55b.
_The control signal is output only to ₃ , 55b ₄ .

Further, when the output power supply voltage of the power supply circuit of another antenna connection target device rises while the power supply circuit of one antenna connection target device has already risen, to the antenna connection target device that started up later. The control signal is output to the output switch group 54 and the output switch group 64 so that the antenna signal is output.

The AND circuits 55b ₁ to 55b ₄ receive not only the control signal from the connection device switching circuit 55a but also the control signal (high level / low level) output from the antenna connection target device 57. The AND circuits 55b ₂ and 55b ₃ among them receive the control signal through the NOT circuit 55c.

Thus, for example, when the output power supply voltage of the power supply circuit of the antenna connection target device 57 rises (that is, a high level signal is input to one input side of the AND circuits 55b _{1 to} 55b ₄ ). When you are)
In addition, when the high level signal is output from the antenna connection target device 57 using the main / sub switching line 58 (that is, the high level signal is input to the other input side of the AND circuits 55b ₁ and 55b ₄ ). AND circuit 55
AND circuits 55b ₁ and 55b are connected to the other input side of b ₂ and 55b ₃ when a low level signal is input).
A high level signal is output from b ₄ .

Therefore, since the control signal (high level) is output to the output switch 54b on the output switch group 54 side, the antenna signal selected by the selection switch 22 is output to the main input terminal via the output switch 54b. On the other hand, on the other hand, on the output switch group 64 side, the output switch 64
Since the control signal (High level) is output to c, the antenna signal selected by the selection switch 32 is output to the sub input terminal via the output switch 64c.

In other words, the antenna signal input to the main input terminal M becomes the antenna signal selected by the selection switch 22, and the antenna signal input to the sub input terminal S is the antenna signal selected by the selection switch 32. Become a signal.

When the output power supply voltage of the power supply circuit of the antenna connection target device 57 rises (that is,
High on one input side of the AND circuits 55b _{1 to} 55b _4.
Level signal is being input) this time, conversely,
From the device 57 to which the antenna is connected to the main / sub switching line 58
When a low level signal is output using the AND circuit (that is, the low level signal is input to the other input side of the AND circuits 55b ₁ and 55b ₄ ).
₂ and 55b _{3 to} the other input side, when a high level signal is input), AND circuits 55b ₂ and 55b
_A high level signal will be output from ₃ .

Therefore, since the control signal (High level) is output to the output switch 54c on the output switch group 54 side, the antenna signal selected by the selection switch 22 is sent to the sub input terminal S via the output switch 54c. On the other hand, the output switch group 64 side outputs the output switch 64.
Since the control signal (high level) is output to b, the antenna signal selected by the selection switch 32 is output to the main input terminal M via the output switch 64b.

In other words, the antenna signal input to the main input terminal M is the antenna signal selected by the selection switch 32, and the antenna signal input to the sub input terminal S is the same as the antenna signal selected by the selection switch 22. Become. Accordingly, the antenna signal output to the sub input terminal S can be output to the main input terminal M based on the instruction from the antenna connection target device 57.

When the decoder driver 53 receives the 2-bit signal (00, 01, 10, 11) sent from the antenna connection target devices 27a, 57, it receives 2 signals.
One output terminal 5 corresponding to the combination of bit signals
3a to 53d (each input terminal 22a to the selection switch 22)
The signal is transmitted from the output terminal corresponding to 22d).

On the other hand, when the decoder driver 63 receives the signal in which the numerical value 1 is added to the 2-bit signal (00, 01, 10, 11) sent from the antenna connection target devices 27a, 57, the received 2 A signal is transmitted from one output terminal 63a to 63d (an output terminal corresponding to each input terminal 32a to 32d of the selection switch 32) corresponding to a combination of bit signals. As a result, the antenna selected by the selection switch 22 and the antenna selected by the selection switch 32 are exclusive.

For example, when a signal "00" is transmitted from the antenna connection target device 27a, the decoder driver 53
Receives a signal of "00", and transmits a control signal (High level signal) from the output terminal 53a corresponding to the input terminal 22a of the selection switch 22, while the decoder driver 63 sends a signal of "01". As a result, the output terminal 6 corresponding to the input terminal 32b of the selection switch 32 is received.
A control signal (high level signal) is transmitted from 3b. As a result, the antenna connection target device 27
The antennas can be freely switched based on the instructions from a and 57.

The signals output from the AND circuits 55b ₁ and 55b ₃ are input to the decoder drivers 63 and 53, respectively.
Reference numerals ₃ and 53 output control signals to the selection switches 32 and 22 only when a high level signal is input from the AND circuits 55b ₁ and 55b ₃ or the connected device switching circuit 55a.

The state in which the high level signal is output from the AND circuit 55b ₁ (that is, the state in which it is permitted to output the control signal from the decoder driver 63 to the selection switch 32) means the output switch. 5
4b is in the ON state (the output switch 54c is in the OFF state), and at the same time, the output switch 64c is in the ON state (the output switch 64b is in the OFF state).

The state in which the high level signal is output from the AND circuit 55b ₃ (that is, the state in which the control signal is permitted to be output from the decoder driver 53 to the selection switch 22) means the output switch. 6
4b is in the ON state (the output switch 64c is in the OFF state), and at the same time, the output switch 54c is in the ON state (the output switch 54b is in the OFF state).

Therefore, the state in which the decoder driver 63 is allowed to output the control signal to the selection switch 32 means that the antenna signal selected by the selection switch 32 is input to the sub input terminal S. Yes,
The state in which the decoder driver 53 is permitted to output the control signal to the selection switch 22 is a case where the antenna signal selected by the selection switch 22 is input to the sub input terminal S. In other words, the antenna switching in the antenna switching device 51 is limited to the antenna on the side connected to the sub input terminal S.

The antenna connection target device 57 here is used.
Has the following two functions (a) and (b). (B) When the reception intensity of the antenna signal input to the main input terminal M exceeds the reception intensity of the antenna signal input to the sub input terminal S, the signal output via the main / sub switching line 58 is inverted. . For example, when outputting a high level signal, output a low level signal,
Conversely, if a low level signal was output, a high level signal is output.

(B) When the reception intensity of the antenna signal input to the sub input terminal S becomes equal to or lower than a predetermined value, a 2-bit signal is transmitted to the decoder drivers 53 and 63. However, at this time, a value obtained by adding (or subtracting) the numerical value 1 to the previously transmitted one is transmitted. For example, last time it was "10"
If you send the signal of, send "11" this time,
Next time, send "00" (for addition).

It should be noted that addition and subtraction are switched when there is an inversion of the signal output through the main / sub switching line 58 and when addition or subtraction is performed twice in succession. . For example, when the signal of "00" was transmitted last time, "01" is transmitted this time and "10" is transmitted next time, but for the next, "11" is added instead of "1" which is the numerical value 1 added. , "01" which is obtained by subtracting the numerical value 1 is transmitted. This is to prevent the antenna connected to the main input terminal M and the antenna connected to the sub input terminal S from being the same.

Next, an example of the operation of the antenna switching device according to the embodiment (4) will be described. When the power switch of the digital television is turned on for the user to watch the digital television (antenna connection target device 57), the power supply circuit of the antenna connection target device 57 supplies power to each unit in the device.

The connected device switching circuit 55a monitors the rise of the output power supply voltage of the power supply circuit, and when the output power supply voltage of the power supply circuit rises, the antenna connection target device in which the output power supply voltage of the power supply circuit rises. 57
The AND circuit 55b outputs the control signal (high-level signal) so that the antenna signal is output to the (digital television).
Output for all _{1 to} 55b ₄ .

At this time, the output terminal 22e of the selection switch 22 is connected to the input terminal 22a (antenna 6a), and the output terminal 32e of the selection switch 32 is the input terminal 3
2b (antenna 6b), and a high-level signal is output from the antenna connection target device 57 via the main / sub switching line 58.

The main input terminal M of the antenna connection target device 57 receives the antenna signal from the antenna 6a at the start-up, and the sub input terminal S has the antenna 6a.
The antenna signal from b will be input.

The subsequent operation will be described separately for cases (i) and (ii). (I) The sub-input terminal S is more than the reception intensity of the antenna signal (from the antenna 6a) input at the main input terminal M.
When the reception strength of the antenna signal (from the antenna 6b) input at (3) exceeds, the signal transmitted from the antenna connection target device 57 through the main / sub switching line 58 is inverted. For example, it is inverted from High level to Low level.

The signal transmitted through the main / sub switching line 58 is Lo
When it becomes a w level signal, AND circuits 55b ₂ and 55b
_A high level signal is output from ₃ and the AND circuit 55b
_Since Low level signals are output from ₁ and 55b ₄ ,
Selected by the selection switch 22 (from the antenna 6a)
The antenna signal is output to the sub input terminal S via the output switch 54c, while the antenna signal (from the antenna 6b) selected by the selection switch 32 is output to the main input terminal M via the output switch 64b. It

(Ii) When the reception intensity of the antenna signal (from the antenna 6b) input to the sub-input terminal S becomes equal to or lower than a predetermined value, the antenna connection target device 57 sends a 2-bit signal (for example, to the decoder drivers 53 and 63). , "01") is transmitted.

Even if the decoder driver 53 receives a 2-bit signal from the antenna connection target device 57, the A
Since the low level signal is received from the ND circuit 55b ₃ , the selection switch 22 is not controlled at all.
On the other hand, when the decoder driver 63 receives a 2-bit signal (for example, “10”) output from the antenna connection target device 37 and added with the numerical value 1, a predetermined output terminal (for example, “10”) is received based on the received signal. , A control signal (high-level signal) is transmitted from the output terminal 63c).

The selection switch 32 is the decoder driver 6
When receiving the control signal from 3, the output terminal 32e and the input terminal 32c (antenna 6c) are connected. Thereby, the antenna signal output to the sub input terminal of the antenna connection target device 57 is transmitted from the antenna 6b to the antenna 6c.
It switches to the antenna signal of.

According to the antenna switching device of the above embodiment (4), the antenna signal selected by the selection switch 22 is supplied to either the main input terminal M or the sub input terminal S of the antenna connection target device 57. Output switch group 54 for outputting to the output switch group, and an output switch group for outputting the antenna signal selected by the selection switch 32 to any one of the main input terminal M / sub input terminal S of the antenna connection target device 57. 64 and further,
The output destination of the antenna signal output from the output switch group 54 and the output destination of the antenna signal output from the output switch group 64 are configured to be exclusive.

That is, when the antenna signal selected by the selection switch 22 is being output to the main input terminal M of the antenna connection target device 57, the antenna signal selected by the selection switch 32 is the sub input terminal S.
When the antenna signal selected by the selection switch 22 is output to the sub input terminal S, conversely, the antenna signal selected by the selection switch 32 is output to the main input terminal M. .

Further, since the antenna signal selected by the selection switch 22 and the antenna signal selected by the selection switch 32 are configured to be exclusive, the main input terminal M / of the antenna connection target device 57 is set. Antenna signals from different antennas can be output to the sub input terminal S.

Further, the output destination of each antenna signal selected by the selection switches 22 and 32 is switched based on the instruction from the antenna connection target device 57, so that the convenience of the antenna connection target device 57 ( For example, the antenna can be freely switched by decreasing the reception intensity of the main input terminal M).

For example, when the reception intensity of the antenna signal input from the sub input terminal S exceeds the reception intensity of the antenna signal input from the main input terminal M, the antenna connection target device 57 switches the antenna. When instructed, the antenna signal output to the main input terminal M and the antenna signal output to the sub input terminal S can be switched.

Further, as described above, since the antenna signal selected by the selection switch 22 and the antenna signal selected by the selection switch 32 are configured to be exclusive, a distributor is provided. There is no need to distribute the antenna signal.

Therefore, since no distribution loss occurs, it is not necessary to provide an amplifier, and the noise figure is not deteriorated and the reception sensitivity can be prevented from lowering. Therefore, the antenna is inexpensive and excellent in performance. A switching device can be realized.

Further, since the antenna signals selected by the selection switches 22 and 32 can be switched based on the instruction from the antenna connection target device 57, the convenience of the antenna connection target device 57 (for example, reduction in reception strength).
The antennas can be freely switched by.

Therefore, for example, without switching the antenna connected to the main input terminal M, the sub input terminal S
By performing only the switching of the antennas connected with, it is possible to realize a diversity system combining the scanning type and the selection type.

In the antenna switching device according to the above embodiments (1) to (4), the antenna connection target device 27a is used.
27c, 37, and 57, a signal line dedicated to the antenna signal switching instruction selected by the selection switches 22 and 32 is provided, but in the antenna switching device 21A according to another embodiment. As shown in FIG. 5, L that prevents passage of the antenna signal is provided between the HPF provided on the antenna signal line and the device to be connected to the antenna.
PFs (low pass filters) 71a to 71c, etc. are connected in series, and signals passed through the LPFs 71a to 71c are FSK.
It may be configured to output to the decoder driver 23 via the decoder 72.

As a result, if the signal is transmitted using the low frequency carrier, the antenna connection target device 27
The signals can be transmitted from a to 27c to the decoder driver 23 using the antenna signal line as a medium. Therefore, the antenna connection target devices 27a to 27
Since it is not necessary to provide another signal line only for inputting the signal from c, the device can be simplified.

FIG. 6 is a block diagram schematically showing a main part of a receiving system adopting the antenna switching device according to the embodiment (5). The case where the receiving system is adopted in a vehicle will be described here.

Reference numeral 81 in the drawing denotes an antenna switching device, and the antenna switching device 81 includes antennas 82a and 82b.
From the antenna signals from the antennas 92a and 92b, and a selection switch 93 for selecting any of the antenna signals from the antennas 92a and 92b.

Antennas 82a, 82b, 92a, 92b
The antennas 82a and 82b are connected to the input terminals 83a and 83b of the selection switch 83, respectively, and the output terminal 83c of the selection switch 83 has a frequency of 30 MHz or higher. HPF through which high frequency antenna signals (that is, antenna signals transmitted from FM radio and television broadcasting stations) can pass
It is connected to one input terminal 87a of the antenna connection target device 87 via a (wide band pass filter) 84, and
2a and 92b are input terminals 93 of the selection switch 93, respectively.
a, 93b, and the output terminal 9 of the selection switch 93.
3c is connected to the other input terminal 87b of the antenna connection target device 87 via the HPF 94.

Further, the selection switch 83 (93) is connected between the HPF 84 (94) and the antenna connection target device 87 (97) via the LPF 85 (95), and L
A resistor R1 (R2) and a capacitor C1 (C1) are connected in parallel between the PF 85 (95) and the selection switch 83 (93), and these resistors R1 (R2) and C1 (C1) are connected.
2) Each is connected to GND at the other end. Note that these resistors R1 (R2) and capacitors C1 (C2)
This prevents the signal output from the antenna connection target device 87 from leaking to GND. Thereby, the signal output from the antenna connection target device 87 can be transmitted to the selection switches 83 and 93 using the antenna signal line. The LPF may be a λ / 2 choke coil or the like.

When the selection switch 83 receives a high level signal, it connects the output terminal 83c and the input terminal 83b (antenna 82a), and when it receives a low level signal, the output terminal 83c and the input terminal 83a ( Antenna 82
b) and is connected.

When the selection switch 93 receives a high level signal, it connects the output terminal 93c and the input terminal 93a (antenna 92b), and when it receives a low level signal, the output terminal 93c and the input terminal 93c. 93b (antenna 92b) is connected.

As a result, a high level signal (for example, 12V) is input from the input terminal 87a of the antenna connection target device 87.
Signal voltage) is output, while a low level signal (for example, from the input terminal 87b of the antenna connection target device 87) is output.
When the signal voltage of 0 V) is output, the antenna signal from the antenna 82a is output to the input terminal 87a, and the input terminal 8a
The antenna signal from the antenna 92a can be output to 7b.

On the contrary, the antenna connection target device 8
A low level signal (for example, 0
V signal voltage) while the input terminal 87b of the antenna connection target device 87 outputs a high level signal (for example, 12 V signal voltage), the input terminal 87
The antenna signal from the antenna 82b can be output to a and the antenna signal from the antenna 92b can be output to the input terminal 87b.

The input terminal 87a of the antenna connection target device 87 is connected to the anode of the diode D1 via the LPF 85, and the input terminal 87b of the antenna connection target device 87 is connected to the anode of the diode D2 via the LPF 95. Since it is connected, it is High from the input terminal 87a.
When the level signal (12V signal voltage) was output, the signal voltage of 12V was output from the cathode side of the diode D1, and the high level signal was not output from the input terminal 87a. Also, when a high level signal is output from the input terminal 87b, a signal voltage of 12V is output from the cathode side of the diode D2.

Therefore, the signal voltage output from the cathode side of these diodes D1 and D2 is applied to the antenna switching device 8
Since the power supply voltage can be set to 1, the device can be simplified.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing a main part of a reception system that employs an antenna switching device according to an embodiment (1) of the present invention.

FIG. 2 is a block diagram schematically showing a main part of a reception system that employs an antenna switching device according to an embodiment (2).

FIG. 3 is a block diagram schematically showing a main part of a reception system that employs an antenna switching device according to an embodiment (3).

FIG. 4 is a block diagram schematically showing a main part of a reception system that employs an antenna switching device according to an embodiment (4).

FIG. 5 is a block diagram schematically showing a main part of a reception system that employs an antenna switching device according to another embodiment.

FIG. 6 is a block diagram schematically showing a main part of a reception system that employs an antenna switching device according to an embodiment (5).

FIG. 7 is a block diagram schematically showing a main part of a receiving system adopting a conventional antenna switching device.

[Explanation of symbols]

21, 21A, 31, 41, 51, 81 Antenna switching device 22, 32 Selection switch 23, 33, 43, 53, 63 Decoder driver 24, 54, 64 Output switch group 25, 35, 45, 55a Connected device switching circuit 26a ~ 26c, 36, 46, 56a to 56c, 66
b, 66c HPF 34, 44 Output switch 42 Phase shift

Claims (10)

[Claims] 1. An antenna switching device comprising a plurality of antennas and a plurality of antenna connection target devices and used in a reception system adopting a diversity system, wherein any one of antenna signals from the plurality of antennas is used. And a first input selecting means for selecting and inputting the antenna signal, and a first inputting means for outputting the antenna signal selected by the first input selecting means to any one of the plurality of antenna connection target devices. Output means, first device determining means for determining an antenna connection target device that should output the antenna signal, and the first device determining means based on the determination by the first device determining means.
A first output control unit for controlling the output unit to output the antenna signal to the antenna connection target device determined by the device determination unit; and, based on an instruction from the antenna connection target device, An antenna switching device comprising: first input control means for switching the antenna signal selected by the first input selection means by controlling the first input selection means. 2. A second input selection means for selecting and inputting any one of the antenna signals from the plurality of antennas, and an antenna signal selected by the second input selection means. The predetermined antenna connection target device outputs the antenna signal by the second output means for outputting to the predetermined antenna connection target device among the plurality of antenna connection target devices, and the first device determination means. When it is determined that the device is to be used, the second output control unit controls the second output unit to output the antenna signal to the predetermined antenna connection target device, and the antenna connection target device A second input for switching the antenna signal selected by the second input selecting means by controlling the second input selecting means based on the instruction And an antenna signal selected by the first input selection means and an antenna signal selected by the second input selection means are exclusive. The antenna switching device according to claim 1. 3. A second input selecting means for selecting and inputting any one of the antenna signals from the plurality of antennas, and an antenna signal selected by the second input selecting means, And a third output unit for outputting to any one of the two or more antenna connection target devices, and the first device determination unit allows any one of the predetermined two or more antenna connection target devices. When it is determined that the device should output the antenna signal, the third output unit controls the third output unit to output the antenna signal to the antenna connection target device determined by the device determining unit. An antenna selected by the second input selecting means by controlling the second input selecting means based on an instruction from the control means and the device to be connected to the antenna. A second input control means for switching the input / output signal, and the antenna signal selected by the first input selection means and the antenna signal selected by the second input selection means are exclusive. The antenna switching device according to claim 1, wherein the antenna switching device is configured as follows. 4. The antenna switching device according to claim 2 or 3, further comprising phase conversion means for converting the phase of the antenna signal selected by the second input selection means. 5. An antenna switching device used in a receiving system adopting a diversity system, comprising: a plurality of antennas; and an antenna connection target device having a main input terminal / sub input terminal for inputting an antenna signal. And a third input selecting means for selecting and inputting any of the antenna signals from the plurality of antennas, and an antenna signal selected by the third input selecting means, A fourth output unit for outputting to any one of a main input terminal / sub input terminal of the device, and controlling the third input selecting unit based on an instruction from the antenna connection target device. A third input control means for switching the antenna signal selected by the third input selection means, and a finger from the antenna connection target device. A fourth output control means for controlling the fourth output means to output the antenna signal selected by the third input selection means to any one of the main input terminal / the sub input terminal. A fourth input selecting means for selecting and inputting any one of the antenna signals from the plurality of antennas, and the antenna signal selected by the fourth input selecting means, Fifth output means for outputting to any one of the main input terminal / sub input terminal, and controlling the fourth input selection means based on an instruction from the antenna connection target device, Fourth input control means for switching the antenna signal selected by the fourth input selection means, and the fifth input control means based on an instruction from the antenna connection target device. A fifth output control means for controlling the output means to output the antenna signal selected by the fourth input selection means to any one of the main input terminal / sub input terminal, and the third output control means. The antenna signal selected by the input selection means and the antenna signal selected by the fourth input selection means are configured to be exclusive, and further, the antenna signal output from the fourth output means. And the output destination of the antenna signal output from the fifth output means are exclusive. 6. The antenna of the third input selecting means and the fourth input selecting means, which is connected to the main input terminal of the antenna connection target device, is switched. On the other hand, on the other hand, the antenna switching device according to claim 5, wherein the input selection means connected to the sub-input terminal of the antenna connection target device is configured to switch the antenna. 7. The fourth output means outputs the antenna signal selected by the third input selection means to the antenna connection target device and one or more antenna connection targets other than the antenna connection target device. A second device determining means for determining an antenna connection target device to output the antenna signal, and the second device determining means based on the determination by the second device determining means. Four
6. Output control means for controlling the output means to output the antenna signal to the antenna connection target device determined by the second device determination means. The antenna switching device according to claim 5 or claim 6. 8. An antenna signal line connecting the plurality of antennas to an antenna connection target device is provided with a first passage means through which an antenna signal can pass, and the first passage means and the antenna connection target device are provided. A first blocking means for blocking the passage of the antenna signal and a passage of the signal transmitted from the antenna connection target device are connected in series between and. The antenna switching device according to any one of 1. 9. A first antenna group including a first antenna and a second antenna, a second antenna group including a third antenna and a fourth antenna, and an antenna. A receiving system adopting a diversity system, which has a first input terminal and a second input terminal for inputting a signal, and is provided with an antenna connection target device for transmitting a signal showing two different significant states An antenna switching device to be used, which is a fifth input selection for selecting and inputting an antenna signal from the first antenna or an antenna signal from the second antenna that configures the first antenna group. Means and a sixth input for selecting and inputting an antenna signal from the third antenna or the antenna signal from the fourth antenna, which constitutes the second antenna group. Together and a-option unit, the first antenna signal line connecting the first input terminal of the antenna connected device to the first antenna group,
A second passage means capable of passing the antenna signal is provided, and while the passage of the antenna signal is blocked between the second passage means and the antenna connection target device, transmission from the antenna connection target device is performed. Second to pass the signal
Blocking means are connected in series, and the fifth input selecting means switches the antennas based on a signal transmitted from the antenna connection target device. The second antenna signal line connecting the second input terminal of the device to be connected to the antenna is also provided with a third passage means through which the antenna signal can pass, and the third passage means and the antenna connection. A third device for blocking the passage of the antenna signal between the target device and a device for transmitting the signal transmitted from the antenna connection target device
Is connected in series, and the sixth input selecting means switches the antenna based on a signal transmitted from the antenna connection target device. 10. The first antenna signal line and the first antenna signal line.
Via the first blocking means, the first rectifying means for flowing the signal passing through the first blocking means in only one direction, the second antenna signal line and the second blocking means. 10. The antenna switching device according to claim 9, further comprising a second rectifying unit that is connected and that allows a signal that has passed through the second blocking unit to flow a current in only one direction.