JP2001016032A - On-vehicle transmitter receiver for etc - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the on-vehicle transmitter receiver for ETC which is inexpensive and does not make the interior appearance of a cabin worse, when fitted to the vehicle by decreasing the number of cables connecting an antenna module and a main body part. SOLUTION: This antenna module 1 is provided with a 1st signal separating circuit 12 which separates signals by filters 23, 24, 25, and 26, the main body part 2 is provided with a 2nd signal separating circuit 32 which separates signals by filters 40, 41, 42, and 43, and the 1st signal separating circuit 12 and 2nd signal separating circuit 32 are connected with a cable 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a non-stop automatic toll collection system (Electronic Toll).
The present invention relates to a vehicle-mounted transceiver for an ETC used in a collection system (hereinafter, referred to as an ETC system).

[0002]

2. Description of the Related Art In an ETC system for a toll road such as an expressway, an ETC transmission / reception terminal installed at a tollgate and an ET mounted on a car by time-division two-way communication.
5.8G ASK-modulated with the on-board transceiver for C
Transmission and reception are performed using the ASK modulated wave in the Hz band, and a predetermined fee is separately collected by transmitting and receiving the signal. An on-vehicle ETC transceiver mounted on a vehicle has a transmitting / receiving antenna mounted on a rearview mirror or the like, a transmitter / receiver main body mounted inside a console box or the like, and the antenna and the transmitter / receiver main body connected by a cable. . Since the cable is attached along the ceiling, the side frame, or the like, it has a length of about 5 m.

FIG. 2 is a block diagram showing one example of a conventional ETC on-board transceiver used in such an ETC system.

This on-vehicle transceiver for ETC is designed to switch between transmission and reception of a signal, and includes an antenna module 51, a main body 52, and a five-wire connecting the antenna module 51 and the main body 52. Cables 53,5
4, 55, 56, and 57. Since these cables 53, 54, 55, 56, 57 are attached along a ceiling, side frames, or the like, they have a length of about 5 m.

The antenna module 51 includes an antenna 58 for both transmission and reception, a band-pass type dielectric filter 59,
Changeover switch 60, receiving circuit section 61 and transmitting circuit section 62
And a voltage adjusting circuit 63, and the receiving circuit unit 61 or the transmitting circuit unit 62 is alternatively connected to the antenna 58 by the changeover switch 60, and is attached to, for example, a rearview mirror or the like.

The receiving circuit section 61 has a low noise amplifier 64 and a mixer 65. The transmission circuit section 62 includes a power amplifier 66, an ASK modulator 67, and a preamplifier 68.
And

A power supply voltage is supplied by a voltage adjusting circuit 63 and a cable 54, and outputs a predetermined voltage (for example, 2.4 V).

The main body 52 has a detection circuit 69, an oscillation circuit 70, a microcomputer 71, and a constant voltage source 72, and is mounted in, for example, a console box in a vehicle.

The detection circuit section 69 has an intermediate frequency amplifier 73, a detector 74, and a demodulation signal amplifier 75, and the oscillation circuit section 70 has a power amplifier 76, an oscillator 77, a phase control loop (PLL) 78, have. The microcomputer 71 includes a signal processing circuit 79 and a signal source circuit 8.
0.

The oscillator 77 is controlled by a signal source circuit 80 in the microcomputer 71 via a phase control loop 78, and its oscillation frequency is 5.835G.
Stabilizes at Hz. The oscillator 77 is connected to the receiving circuit section 61 and the transmitting circuit section 62 via the power amplifier 76 and the cable 57. Since the oscillation signal has a high frequency, the amount of attenuation in the cable 57 is large, and the power amplifier 7
6 is required.

[0013] One end of the cable 53 is connected to the receiving circuit section 61, and the other end is connected to the detection circuit section 69. One end of the cable 54 is connected to the voltage adjustment circuit 63, and the other end is connected to the constant voltage source 72. Also,
One end of the cable 55 is connected to the changeover switch 60,
The other end is connected to the signal source circuit 80. In addition, cable 5
One end of 6 is connected to the ASK modulator 67, and the other end is connected to the signal source circuit 80. Further, one end of the cable 57 is connected to the reception circuit section 61 and the transmission circuit section 62, and the other end is connected to the oscillation circuit section 70.

When the ASK modulated wave is received, the signal source circuit 8
0 controls the changeover switch 60 so that the antenna 5
8 and the mixer 65 are connected, and the 5.835 GHz oscillation signal output from the oscillator 77 is input to the mixer 65 of the receiving circuit unit 61 as a local oscillation signal.

When an ASK modulated wave is transmitted from an antenna (not shown) of an ETC transmission / reception terminal station installed at a tollgate to a car entering the tollgate, the ASK modulated wave is received by an antenna 58, and is received by a dielectric filter. Unnecessary frequency components are removed at 59,
After being amplified by the low noise amplifier 64, the mixer 65
Is input to The mixer 65 converts the ASK modulated wave into an oscillation signal (frequency is 5.835 GHz) output from the oscillator 77.
z) and frequency-converted to an intermediate frequency signal (frequency is 40 MHz).

The intermediate frequency signal is supplied to the coaxial cable 5
3 and is input to the detection circuit section 69. The intermediate frequency signal input to the detection circuit section 69 is converted into an intermediate frequency amplifier 73
, And is subjected to envelope detection by a detector 74 to become a demodulated signal, which is input to a demodulated signal amplifier 75.
The demodulated signal amplifier 75 inputs the amplified demodulated signal to the signal processing circuit 79 and also inputs a CD (Carrier Detect) signal indicating that the ASK modulated wave has been received to the signal processing circuit 79.

On the other hand, when transmitting an ASK modulated wave, the signal source circuit 80 controls the changeover switch 60 to connect the antenna 58 and the transmission circuit section 62,
The 5.835 GHz oscillation signal output from the oscillator 77 is input to the preamplifier 68 of the transmission circuit section 62 as a carrier.

The carrier amplified by the preamplifier 68 and a modulated signal (digital signal) output from the signal source circuit 80
Are input to the ASK modulator 67, and an ASK modulated wave is output. The ASK modulated wave is amplified by the power amplifier 66, passes through the dielectric filter 59, and is transmitted from the antenna 58 to the antenna of the ETC transmitting / receiving terminal station installed at the tollgate.

[0017]

However, since the number of cables connecting the antenna module to the main body is as large as five, the cost of the product has been increased. In addition, when mounting the on-board transceiver for ETC on a vehicle, there are cases where cables need to be mounted along the side frame in the vehicle room without as many as five cables being able to enter the side frame, and the appearance of the vehicle room is improved. Sometimes it got worse.

Therefore, an object of the present invention is to reduce the number of cables for connecting the antenna module and the main body, thereby reducing the cost and improving the appearance of the ET when attached to a vehicle.
An object of the present invention is to provide an on-vehicle transceiver for C.

[0019]

In order to solve the above-mentioned problems, a vehicle-mounted transceiver for ETC of the present invention comprises an antenna module, a main body, and a cable connecting the antenna module and the main body. The antenna module further includes a transmitting / receiving antenna, a mixer that converts a received signal received by the antenna into an intermediate frequency signal having a lower frequency than the received signal, and modulates a carrier with transmission data and outputs the modulated carrier to the antenna. Modulator, a switch for selectively connecting the antenna to the mixer or the ASK modulator by a transmission / reception switching signal, and at least the intermediate frequency signal, the carrier, the transmission data, and the transmission / reception switching signal. A first signal separation circuit that separates the intermediate frequency signal from each other, and a detector that detects the intermediate frequency signal, An oscillator that outputs an oscillation signal, a signal source circuit that outputs the transmission data and the transmission / reception switching signal, and a second circuit that separates at least the intermediate frequency signal, the oscillation signal, the transmission data, and the transmission / reception switching signal from each other. A signal separation circuit was provided, and the first signal separation circuit and the second signal separation circuit were connected by the cable.

Further, the on-vehicle transceiver for ETC of the present invention comprises:
A multiplier is provided in the antenna module, and the oscillating signal is converted into the carrier by the multiplier and ASK is performed.
Input to the modulator.

Further, in the vehicle-mounted transceiver for ETC according to the present invention, the main unit includes a power supply source, and a superimposing circuit for superimposing the transmission / reception switching signal on a voltage supplied from the power supply source. A module that receives the transmission / reception switching signal on which the power supply voltage is superimposed and outputs a predetermined voltage, and a switching switch driving circuit that receives the transmission / reception switching signal on which the power supply voltage is superimposed and switches the switch And

Further, in the vehicle-mounted transceiver for ETC of the present invention, the superimposing circuit is configured by connecting a switch transistor and a voltage dividing circuit in series, and the changeover switch driving circuit superimposes the power supply voltage. And a comparator for comparing the transmitted / received switching signal with a predetermined voltage.

Also, in the on-board ETC transceiver for ETC according to the present invention, the first signal separating circuit includes a first intermediate frequency filter for passing the intermediate frequency signal, and a first transmitting filter for transmitting the transmission original signal. An original signal filter, a first oscillation signal filter for passing the oscillation signal, and a first antenna switching signal filter for passing the antenna switching signal, wherein the mixer has the first intermediate frequency Connected to a filter, the ASK modulator is connected to the first transmission original signal filter and the first oscillation signal filter, the antenna switch is connected to the first antenna switching signal filter, The second signal separation circuit includes a second intermediate frequency filter that passes the intermediate frequency, a second transmission source signal filter that passes the transmission original signal, and an oscillator. A second oscillating signal filter for passing the signal, and a second antenna switching signal filter for passing the antenna switching signal, wherein the detector is connected to the second intermediate frequency filter, the oscillator Is connected to the second oscillation signal filter, and the integrated circuit is connected to the second transmission source signal filter and the second antenna switching signal filter, respectively.

Further, in the vehicle-mounted transceiver for ETC according to the present invention, the first intermediate frequency filter and the second intermediate frequency filter have a pass band of at least 40 MHz. The second transmission source signal filter has a passband of at least 2 MHz, and the first oscillation signal filter and the second oscillation signal filter have a passband of a predetermined frequency of at least 1 GHz or more, The first antenna switching signal filter and the second antenna switching signal filter have at least a predetermined frequency of 1 MHz or less as a pass band.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An on-vehicle transceiver for ETC according to the present invention will be described with reference to FIG.

The on-board ETC transceiver for ETC is designed to switch between transmission and reception of a signal. The coaxial type transceiver for connecting the antenna module 1, the main body 2, and the antenna module 1 to the main body 2 is provided. Cable 3.

The antenna module 1 includes a transmitting / receiving antenna 4, a band-pass dielectric filter 5, a changeover switch 6, a receiving circuit section 7, a transmitting circuit section 8, a multiplying circuit section 9, a voltage adjusting circuit 10, It has a changeover switch driving circuit 11 and a first signal separation circuit 12, and the changeover switch 6 selectively connects the reception circuit section 7 or the transmission circuit section 8 to the antenna 4 and is attached to, for example, a rearview mirror or the like. .

The receiving circuit section 7 has a low noise amplifier 13 and a mixer 14. The transmission circuit section 8 has a power amplifier 15, an ASK modulator 16, and a preamplifier 17. Further, the multiplier circuit section 8 has a trap circuit 18 and a multiplier 19. The changeover switch driving circuit 11 has an operational amplifier 20 and voltage dividing circuits 21 and 22. Further, the first signal separation circuit 12 includes a first intermediate frequency filter 23 and a first transmission data filter 24.
And a first transmission / reception switching signal filter 25 and a first oscillation signal filter 26. These circuits are supplied with a voltage of 2.4 V from the voltage adjustment circuit 10.

The main body 2 has a detection circuit 27, an oscillation circuit 28, a microcomputer 29, a constant voltage source 30, a superimposition circuit 31, and a second signal separation circuit 32, for example, in a console box in a car. It is attached.

The detection circuit section 27 includes an intermediate frequency amplifier 33, a detector 34, and a demodulation signal amplifier 35. The oscillation circuit section 28 includes an oscillator 36 and a phase control loop (PLL).
37. The superimposing circuit 31 has a switch transistor 38 and a voltage dividing circuit 39. The second signal separation circuit 32 includes a second intermediate frequency filter 40, a first transmission data filter 41, a first transmission / reception switching signal filter 42, and a first oscillation signal filter 4.
And 3. Further, the microcomputer 29 has a signal processing circuit 44 and a signal source circuit 45.

Then, one end of the cable 3 is connected to the first signal separation circuit 12 in the antenna module 1, and the other end is connected to the second signal separation circuit 32 in the main body 2. Since the cable 3 is attached along a ceiling, a side frame, or the like, it has a length of about 5 m.

The oscillator 36 is controlled by a signal source circuit 45 in the microcomputer 29 via a phase control loop 37, and its oscillation frequency is 2.9175
Stabilizes at GHz. The 2.9175 GHz oscillation signal output from the oscillator 36 is input to the multiplier 19 via the cable 3 and is doubled by the multiplier 19 to be a 5.835 GHz carrier wave or a local oscillation signal. After the oscillation signal is attenuated by the trap circuit 18, the oscillation signal is output to the reception circuit unit 7 and the transmission circuit unit 8.

The 2.9175 GHz oscillating signal passes through the second oscillating signal filter 43 and the first oscillating signal filter 26 composed of a high-pass filter (cutoff frequency is 2.5 GHz), but the other filters Cannot pass through, so that the oscillation signal does not leak to other circuits.

When receiving the ASK modulated wave, the signal source circuit 4
5, the switching transistor 38 of the superimposing circuit 31 is turned on, and the power supply voltage of 3.0 V output from the constant voltage source 30 is changed to 2.4 V by the voltage dividing circuit 39, so that the second signal separating circuit 32, The signal is input to the voltage adjusting circuit 10 and the changeover switch driving circuit 11 through the cable 3 and the first signal separating circuit 12. In the changeover switch driving circuit 11, the voltage of 2.4V output from the voltage adjusting circuit 10 is divided by the voltage dividing circuit 21 to apply the voltage of 1.8V to the non-inverting input terminal of the operational amplifier 20, and the first signal The voltage of 2.4 V transmitted from the separation circuit 12 is divided by the voltage dividing circuit 22 and a voltage of 1.6 V is applied to the inverting input terminal of the operational amplifier 20. Then, the voltage of the output terminal of the operational amplifier 20 increases, and the antenna 4 and the receiving circuit unit 7 are connected.
Further, the transmission switching signal passes through the first transmission / reception switching signal filter 25 and the second transmission / reception switching signal filter 42, which are constituted by low-pass filters (cutoff frequency 1 MHz), but cannot pass through other filters. The signal does not leak to other circuits.

At this time, 4.
The 835 GHz oscillation signal is input to the mixer 14 of the receiving circuit unit 7 as a local oscillation signal.

When an ASK modulated wave is transmitted from an antenna (not shown) of an ETC transmission / reception terminal station installed at a tollgate to a car entering the tollgate, the ASK modulated wave is received by the antenna 4 and is subjected to a dielectric filter. At 5, unnecessary frequency components are removed, amplified by the low noise amplifier 13, and then input to the mixer 14. In the mixer 14, a local oscillation signal (frequency is 5.835) output from the multiplication circuit unit 9 with the ASK modulated wave
GHz and mixed with an intermediate frequency signal (frequency is 40 MHz)
z).

The intermediate frequency signal is supplied to the first intermediate frequency filter 23 of the first signal separation circuit 12, the cable 3,
The second intermediate frequency filter 40 of the second signal separation circuit 32
And is input to the detection circuit unit 27. The intermediate frequency signal input to the detection circuit unit 27 is
, And is subjected to envelope detection by a detector 34 to become a demodulated signal, which is input to a demodulated signal amplifier 35.
The demodulated signal amplifier 35 inputs the amplified demodulated signal to the signal processing circuit 44 and also inputs a CD (Carrier Detect) signal indicating that the ASK modulated wave has been received to the signal processing circuit 44.

The 40 MHz intermediate frequency signal passes through the first intermediate frequency filter 23 and the second intermediate frequency filter 42, which are band pass filters (pass band 40 MHz), but cannot pass through other filters. The frequency signal does not leak to other circuits.

On the other hand, at the time of transmitting the ASK modulated wave, the switch transistor 38 of the superimposing circuit 31 is turned off by the signal source circuit 45, and the constant voltage source 30 outputs the signal.
The power supply voltage of 0 V is used as it is in the second signal separation circuit 3.
2, through the cable 3 and the first signal separation circuit 12, and is input to the voltage adjustment circuit 10 and the changeover switch drive circuit 11. In the changeover switch drive circuit 11, the voltage adjustment circuit 1
The voltage of 2.4 V output from the first signal separation circuit 12 is applied to the non-inverting input terminal of the operational amplifier 20 by applying a voltage of 1.8 V to the non-inverting input terminal of the operational amplifier 20. The voltage is divided by the voltage dividing circuit 22 and the operational amplifier 2
A voltage of 2.0 V is applied to the 0 inverting input terminal. Then, the voltage of the output terminal of the operational amplifier 20 decreases, the antenna 4 and the transmission circuit unit 8 are connected, and the 5.835 GHz oscillation signal output from the multiplication circuit unit 9 is used as a carrier before the transmission circuit unit 8. Input to the operational amplifier 17.

The carrier amplified by the preamplifier 17 is AS
A modulated signal (digital signal) that is input to the K modulator 16 and output from the signal source circuit 45 passes through the second signal separation circuit 32, the cable 3, and the first signal separation circuit 12, and receives the ASK signal. The signal is input to the modulator 16 and an ASK modulated wave is output. The ASK modulated wave is amplified by the power amplifier 15, passes through the dielectric filter 5, and is transmitted from the antenna 4 to the antenna of the ETC transmitting / receiving terminal station installed at the tollgate. The modulated signal is transmitted to a first transmission data filter 24 composed of a band pass filter (pass band is 2 MHz band).
And the second transmission data filter 41 but not the other filters, so that the modulated signal does not leak to other circuits.

[0041]

As described above, the on-vehicle transceiver for ETC of the present invention has the antenna module provided with the first signal separation circuit, the main body provided with the second signal separation circuit, and the first signal separation circuit. And the second signal separation circuit are connected by a cable, the number of cables connecting the antenna module and the main body can be reduced, and the cost of the product can be reduced. Also, when mounted on the vehicle, the cables can be accommodated in the side frames, so that the appearance in the vehicle interior is improved.

The on-vehicle transceiver for ETC according to the present invention comprises:
A multiplier is provided in the antenna module, and the oscillation signal is converted into a carrier wave by the multiplier, and is output.Therefore, the frequency of the oscillation signal passing through the cable can be reduced, and the loss in the cable is reduced. Is unnecessary, and the size of the device can be reduced.

Also, since the transmission / reception switching signal is superimposed on the power supply voltage and sent to the antenna module from the main body of the vehicle-mounted ETC transceiver of the present invention, the power supply voltage is transmitted to the antenna module via a cable for transmitting and receiving signals. Can be supplied.

Further, the superposition circuit of the vehicle-mounted ETC transceiver for ETC according to the present invention is configured by connecting a switch transistor and a voltage dividing circuit in series, and the changeover switch driving circuit performs a transmission / reception switching signal on which the power supply voltage is superimposed. Is compared with a predetermined voltage, the transmission / reception switching signal can be superimposed on the power supply voltage with a simple configuration, and the device can be downsized.

Further, the first signal separating circuit of the on-board ETC transceiver for ETC according to the present invention comprises a first intermediate frequency filter for passing an intermediate frequency, a first transmission data filter for transmitting transmission data, and an oscillation signal. And a first transmission / reception switching signal filter for passing a transmission / reception switching signal. The mixer is connected to the first intermediate frequency filter, and the ASK modulator is One transmission data signal filter and a first oscillation signal filter, a switch is connected to the first transmission / reception switching signal filter, and a second signal separation circuit is configured to pass an intermediate frequency of the second intermediate frequency. A filter, a second transmission data filter that passes transmission data, a second oscillation signal filter that passes an oscillation signal, and a second transmission / reception switching signal that passes an antenna switching signal A detector connected to the second intermediate frequency filter, an oscillator connected to the second oscillation signal filter, and a signal source circuit connected to the second transmission data filter and the second transmission / reception filter. Since they are respectively connected to the switching signal filter, each signal can be separated with a simple configuration, and the size of the device can be reduced.

The on-vehicle transceiver for ETC according to the present invention comprises:
The pass bands of the first intermediate frequency filter and the second intermediate frequency filter are 40 MHz, and the pass bands of the first transmission data filter and the second transmission data filter are 2 MHz.
z, the pass band of the first oscillation signal filter and the second oscillation signal filter is a predetermined frequency of 1 GHz or more,
Since the pass band of the first transmission / reception switching signal filter and the second transmission / reception switching signal filter is a predetermined frequency of at least 1 MHz or less, the frequency bands of the respective signals are significantly different, and the signals can be accurately separated.

[Brief description of the drawings]

FIG. 1 is a block diagram of an on-vehicle transceiver for ETC of the present invention.

FIG. 2 is a block diagram of a conventional ETC in-vehicle transceiver.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna module 2 Body part 3 Cable 4 Antenna 5 Dielectric filter 6 Changeover switch 7 Receiving circuit part 8 Transmitting circuit part 9 Multiplier circuit part 10 Voltage adjustment circuit 11 Changeover switch drive circuit 12 First signal separation circuit 13 Low noise amplifier 14 Mixer 15 Power amplifier 16 ASK modulator 17 Preamplifier 18 Trap circuit 19 Multiplier 20 Operational amplifier 21 Voltage divider 22 Voltage divider 23 First intermediate frequency filter 24 First transmission data filter 25 First transmission / reception switching signal Filter 26 first oscillation signal filter 27 detection circuit section 28 oscillation circuit section 29 microcomputer 30 constant voltage source 31 superposition circuit 32 second signal separation circuit 33 intermediate frequency amplifier 34 detector 35 demodulation signal amplifier 36 oscillator 37 phase control loop 38 switch transistor 39 voltage dividing circuit 40 second intermediate frequency filter 41 second transmission data filter 42 second transmission / reception switching signal filter 43 second oscillation signal filter 44 signal processing circuit 45 signal source circuit 51 antenna module 52 main body 53 cable 54 Cable 55 Cable 56 Cable 57 Cable 58 Antenna 59 Dielectric filter 60 Changeover switch 61 Reception circuit unit 62 Transmission circuit unit 63 Voltage adjustment circuit 64 Low noise amplifier 65 Mixer 66 Power amplifier 67 ASK modulator 68 Preamplifier 69 Detection circuit unit Reference Signs List 70 oscillation circuit section 71 microcomputer 72 constant voltage source 73 intermediate frequency amplifier 74 detector 75 demodulation signal amplifier 76 power amplifier 77 oscillator 78 phase control loop 79 signal processing circuit 80 signal source circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) AB12 AC08 AC10 BA02

Claims (6)

[Claims] An antenna module, a main body, and a cable connecting the antenna module and the main body. The antenna module has an antenna for both transmission and reception, and a reception signal received by the antenna. A mixer that converts the received signal into an intermediate frequency signal having a lower frequency, an ASK modulator that modulates a carrier wave with transmission data and outputs the same to the antenna, and transmits the antenna to the mixer or the ASK modulator by a transmission / reception switching signal. A first switch for selectively separating the intermediate frequency signal, the carrier, the transmission data, and the transmission / reception switching signal from each other; and A detector for detecting a frequency signal, an oscillator for outputting an oscillation signal, and a signal for outputting the transmission data and the transmission / reception switching signal. Signal circuit, and a second signal separation circuit that separates at least the intermediate frequency signal, the oscillation signal, the transmission data, and the transmission / reception switching signal from each other, the first signal separation circuit and the second signal separation circuit. An ETC on-vehicle transmitter / receiver, wherein a signal separation circuit is connected with the cable. 2. The ET according to claim 1, wherein a multiplier is provided in the antenna module, and the oscillation signal is converted into the carrier by the multiplier and output.
On-board transceiver for C. 3. The main body unit has a power supply source and a superimposing circuit that superimposes the transmission / reception switching signal on a voltage supplied from the power supply source, wherein the antenna module has the power supply voltage superimposed thereon. A voltage adjusting circuit that receives a transmission / reception switching signal and outputs a predetermined voltage, and a switching switch driving circuit that receives the transmission / reception switching signal on which the power supply voltage is superimposed and switches the switching switch. 3. The in-vehicle transceiver for ETC according to 1 or 2. 4. The superimposing circuit is configured by connecting a switch transistor and a voltage dividing circuit in series, and the changeover switch driving circuit compares a transmission / reception switching signal on which the power supply voltage is superimposed with a predetermined voltage. The vehicle-mounted transceiver for ETC according to claim 3, comprising a comparator. 5. The first signal separation circuit includes a first intermediate frequency filter that passes the intermediate frequency signal, a first transmission data filter that passes the transmission data, and a second signal that passes the oscillation signal. One oscillation signal filter, and a first transmission / reception switching signal filter for passing the transmission / reception switching signal, wherein the mixer is connected to the first intermediate frequency filter, and the ASK modulator is the One transmission data filter and the first oscillation signal filter, the switch is connected to the first transmission / reception switching signal filter, and the second signal separation circuit passes the intermediate frequency. A second intermediate frequency filter, a second transmission data filter that passes the transmission data,
A second oscillation signal filter for passing the oscillation signal,
A second transmission / reception switching signal filter that passes the transmission / reception switching signal, the detector is connected to the second intermediate frequency filter, and the oscillator is connected to the second oscillation signal filter, 5. The ETC on-board transceiver according to claim 1, wherein the signal source circuit is connected to the second transmission data filter and the second transmission / reception switching signal filter, respectively. 6. The first intermediate frequency filter and the second intermediate frequency filter have a pass band of at least 40 MHz, and the first transmission data filter and the second transmission data filter have at least 2 MHz. Is a pass band, and the first oscillation signal filter and the second oscillation signal filter have a predetermined frequency of at least 1 GHz or more as a pass band, and the first transmission / reception switching signal filter and the second 6. The in-vehicle ETC transmitter / receiver according to claim 5, wherein the transmission / reception switching signal filter has a predetermined frequency of at least 1 MHz or less as a pass band.