JP2002279463A - On-vehicle testing apparatus for etc - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle testing apparatus for ETC capable of simplifying and shortening the required time for the performance measuring test of an ETC vehicle-mounted device, without having to change the setting of the vehicle-mounted device in the state of actually performing a communication. SOLUTION: This on-vehicle testing apparatus for ETC comprises a communication sequence testing means for monitoring the advancement of the transmitting and receiving sequence of the signals while updating the signals to be transmitted to and received from a vehicle-mounted device side, according to the advancement of the transmission and receiving; an output signal measurement means for measuring the frequency and level of the received signals, by receiving the signals received from the vehicle-mounted device; a level control means for outputting the transmitted signals level-regulated according to level control signals; and a control means for controlling these means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tester for an ETC (Electronic Toll Collection) on-board unit for performing a performance measurement test of an on-board unit of the ETC.

[0002]

2. Description of the Related Art On a toll road, information necessary for toll collection is exchanged between a roadside apparatus and an on-vehicle device mounted on a vehicle by wireless communication means, and a toll road user travels on a non-stop road. An automatic toll collection system (ETC) that collects tolls has been developed and is being deployed.

FIG. 7 shows an outline of an ETC system configuration. A roadside apparatus 70 is composed of a roadside wireless device 71 and a roadside antenna 72 attached to a structure 73. The roadside device 70 is provided at a tollgate on a toll road or the like. On the other hand, the vehicle 80 passing through the toll road includes
The vehicle-mounted device 8 is located at a position where transmission and reception can be performed with the roadside antenna 72.
1 is attached.

[0004] In addition to components necessary for communication with the roadside device 70, such as an antenna, a control unit, and a display unit, an IC card for toll payment is inserted into the vehicle-mounted device 81 (these are not shown). are doing).

[0005] As shown in FIG. 7, the ETC is a short-range communication (D) that performs communication in a very narrow area (several meters to several tens of meters).
SRC: Dedicated Short Range Communication) is used. When the vehicle 80 approaches the roadside device 70, the wireless system of the vehicle-mounted device 81 and the roadside wireless device 71 mutually exchange information necessary for toll collection by wireless communication means. Then, the toll is settled on the IC card, and necessary data accompanying the toll is recorded in both the vehicle-mounted device 81 and the roadside apparatus 71.

In order to operate this ETC system,
It goes without saying that the reliability of the roadside equipment value is guaranteed, but in particular, it is necessary that the normal operation of the vehicle-mounted device mounted on each vehicle is ensured.

[0007] Therefore, as a performance measurement test of the vehicle-mounted device for ETC, a communication sequence operation verification test, a vehicle-mounted device output level verification test, a vehicle-mounted device output frequency verification test, and a vehicle-mounted device reception sensitivity test have been conventionally performed. Has been done.

[0008] Specifically, the test of each of these items is performed by performing communication with the vehicle-mounted device using a communication test device in the communication sequence test and confirming whether or not the communication is performed normally. In the measurement of the output level of the vehicle-mounted device, the vehicle-mounted device is set to the continuous transmission state (modulation degree is equivalent to the normal use state) modulated by the standard coded test signal at the specified transmission rate, and the output terminal is set to the peak power meter. The measurement of the output frequency of the on-vehicle device is performed by setting the on-vehicle device to the continuous transmission state of the unmodulated carrier and connecting a frequency counter to the output terminal for measurement. In addition, the sensitivity measurement of the vehicle-mounted device is performed by providing a test terminal for measuring an error rate in the vehicle-mounted device and performing measurement using an error rate measurement device.

[0009]

As described above, in the performance measurement test of the conventional vehicle-mounted device, since different performance measurement tests are individually performed, the setting of the vehicle-mounted device is changed according to the test item. It is necessary to create four types of measurement systems and to prepare various types of measuring instruments. Therefore, these performance measurement tests take a long time, and the place where each measurement test is performed,
Preparation of measuring instruments was necessary.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and makes it possible to easily perform a performance measurement test of an ETC vehicle-mounted device without changing settings in a state where the vehicle-mounted device is actually communicating. , The required time can be shortened, E
An object of the present invention is to provide a tester for a vehicle-mounted TC.

[0011]

According to a first aspect of the present invention, there is provided a tester for an ETC vehicle-mounted device, which transmits a signal to be transmitted to and received from an ETC vehicle-mounted device (hereinafter referred to as a vehicle-mounted device).
Communication sequence test means for monitoring the progress of the transmission / reception sequence while updating as the transmission / reception sequence progresses, output signal measurement means for receiving a signal received from the vehicle-mounted device and measuring the frequency and level of the received signal; A level control means for receiving a transmission signal output from the communication sequence test means and outputting a transmission signal whose level has been adjusted in accordance with a level control signal; A transmitting / receiving separating unit that outputs a signal from the outside to a receiving terminal and supplies the signal to the communication sequence testing unit and the output signal measuring unit, the communication sequence testing unit, the output signal measuring unit, and the level. Main control means for controlling the control means.

According to the tester for an on-board ETC device according to the first aspect, the performance measurement test of the on-board ETC device does not need to change the setting of the on-board ETC device according to the test content, and the communication between the on-board device and the on-board device is actually performed. The operation can be easily performed while the operation is being performed, and the required time can be reduced.

According to a second aspect of the present invention, there is provided a tester for an on-board ETC device according to the first aspect of the present invention, wherein the communication sequence test means includes a frame from the side of the tester for the on-board ETC device (hereinafter referred to as the tester side). Transmission of a control message channel (hereinafter, FCMC) signal, reception of an activation channel (hereinafter, ACTC) signal from the vehicle-mounted device, and reception of a beacon service table (hereinafter, BST) from the tester side.
Transmission of a signal, reception of a vehicle service table (hereinafter, VST) signal from the vehicle-mounted device, transmission of a set primitive (hereinafter, SET) signal from the tester, and reception of the signal from the vehicle-mounted device A primitive (hereinafter, GET) signal is received, a release signal is transmitted from the tester, and a wireless call number channel (hereinafter, WCN) is transmitted from the vehicle-mounted device.
C) While monitoring the progress of a series of communication sequences for signal reception, it is determined whether or not each of the signals transmitted from the tester has been correctly received by the vehicle-mounted device. ) A judgment is made based on a signal, and the quality of each of the signals transmitted from the vehicle-mounted device is judged by inspecting the signal. If any of the communication sequences is judged as “No”, the sequence is determined to be abnormally terminated. The sequence is normally terminated when it is determined to be "good" at any stage.

According to the second aspect of the present invention, the signal transmission from the tester side to the vehicle-mounted device side and the signal transmission from the vehicle-mounted device side to the tester side are individually determined for each stage. Thus, the communication sequence test can be reliably performed, and when the sequence ends abnormally, it is possible to confirm at which stage of the on-vehicle device or the tester the result is "No". Therefore, it is easy to deal with the abnormal termination of the sequence.

According to a third aspect of the present invention, there is provided a tester for an on-board ETC unit according to the first and second aspects, wherein the output level of the level control means is controlled by the main control means. The communication sequence test is performed by setting the upper limit level of the reception sensitivity, the lower limit of the reception sensitivity, and the non-response level of the reception sensitivity, respectively.
Is determined, and when the reception sensitivity is at the non-response level, it is determined to be “good” when the sequence is abnormally terminated.

According to the third aspect of the present invention, the level of a transmission signal from the tester side to the on-vehicle device is determined by:
The upper limit of the receiving sensitivity of the ETC on-board unit by the level control means,
By setting the lower limit and the no-response level, the reception sensitivity of the on-board ETC device can be tested by the same communication sequence test.

According to a fourth aspect of the present invention, there is provided a tester for an on-board ETC device according to the first aspect of the present invention, which is encoded by a Manchester method from the on-board device side.
The output signal measuring means for receiving the signal modulated by the SK (amplitude shift keying) method and measuring the frequency and level of the received signal mixes the signal frequency from the vehicle-mounted device with the local oscillation signal by the mixer. Converting to a low frequency, converting to a digital signal of a predetermined sampling frequency, and converting the frequency of the received signal to FFT (fast Fourier transform) of the digital signal for a predetermined period to obtain a frequency having the largest amplitude value,
From this frequency and the local oscillation signal frequency, the level of the received signal is determined by the average value of the peak value of the logical value “1” of the absolute value of the absolute value of the digital data or the digital data obtained by oversampling the digital data.
It is characterized by seeking.

According to the tester for an on-board ETC device according to the fourth aspect, since the signal frequency from the on-board ETC device is converted into a low frequency and then the digital signal processing is performed, the signal processing is easy. In addition, since the transmission / reception signal of the ETC is modulated by the ASK method, it is possible to easily and accurately receive the reception signal by using the fact that the frequency having the largest amplitude value among the frequency data subjected to the FFT processing becomes the carrier frequency. Can be obtained. Also, since the transmission and reception signals of ETC are encoded by the Manchester method,
By using the fact that the logical value "1" is included in each symbol, the level of the received signal can be easily and accurately obtained.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an ETC according to an embodiment of the present invention.
FIG. 2 is a block diagram showing the overall configuration of the vehicle-mounted device tester 10, in which the tester 10 and an ETC vehicle-mounted device 20 to be tested are connected by an RF cable.

The system controller 11 works together with the main control circuit 12 as main control means for controlling the tester 10. The onboard unit 2 is operated by the operation of the system controller 11.
When the test of “0” is started, transmission data is generated by the protocol control circuit 13 and the transmission data is supplied to the high frequency unit 14. The high-frequency section 14 encodes the transmission data by the Manchester method, modulates the transmission data by the ASK (amplitude shift keying) method, puts it on a carrier of 5.8 GHz band, and transmits the transmission signal T.
x is transmitted to the vehicle-mounted device 20 from the output terminal via the level control unit 15 and the transmission / reception switch 16.

The level control unit 15 controls the level of the input transmission signal in accordance with the control signal from the main control circuit 12 and transmits the signal. In addition, the carrier in the 5.8 GHz band is actually an A mode of 5795 MHz and a B mode of 5805 MHz.
Mode, and any one of the modes is used.

When the vehicle-mounted device 20 receives the transmission signal from the tester 10, it generates response data corresponding to the received data, encodes the response data in the same Manchester system, and executes ASK.
The signal is modulated by a method and transmitted to the tester 10 on a carrier wave of 5.8 GHz band.

The signal transmitted from the vehicle-mounted device 20 is supplied to the divider 17 via the transmission / reception switch 16, divided by the divider at a predetermined ratio, and supplied to the high-frequency unit 14 and the output signal measuring circuit 18. Is done.

The signal from the vehicle-mounted device 20 sent to the high frequency unit 14 is detected, and the data is transmitted to the protocol control circuit 13.
To be analyzed and a pass / fail judgment is made. The determination result is sent to the main control circuit 12 and the system controller 11 to be displayed and generate the next transmission data.
Similarly, it is sent to the vehicle-mounted device 20 side. In this way, the transmission and reception of data between the tester 10 and the vehicle-mounted device 20 are repeated, and the communication sequence operation of the vehicle-mounted device is tested.

On the other hand, the signal from the vehicle-mounted device 20 sent to the output signal measuring circuit 18 is converted into a digital signal, and the data is transferred to the system controller 11 via the main control circuit 12 and is transmitted from the vehicle-mounted device 20. The output level and frequency of the carrier are analyzed and determined.

The sequence operation of the vehicle-mounted device for repeatedly transmitting and receiving data between the tester 10 and the vehicle-mounted device 20 is performed by transmitting the transmission output level from the level control section 15 to the ETC.
It is performed by changing the reception upper limit level, the reception lower limit level, and the reception non-response level specified in ARIB-STD-T55 (the item number of the standard association for toll road automatic toll collection system of the Radio Industry Association) By determining the transmission / reception status in those cases, a reception sensitivity test of the vehicle-mounted device 20 is performed.

The test / measurement using the tester 10 confirms whether the communication sequence operation of the vehicle-mounted device 20 is performed normally, and measures the output level and frequency of the transmission signal from the vehicle-mounted device 20; Since the reception sensitivity of the vehicle-mounted device 20 with respect to the transmission signal of the reception upper limit level, the reception lower limit level, and the reception non-response level from the tester 10 can be tested, simplification of the test / measurement, time reduction, and space saving can be achieved.

Prior to the description of each test measurement using the tester 10, the configuration of an ETC communication frame and the function and role of each signal will be described.

As shown in FIG. 2, the communication frame of ETC has a standard frame configuration of a 5-slot TDMA system. The size of each slot is 800 bits, and the number of slots is not limited to 5 but may be other.

A frame control message channel (hereinafter, FCMC) is always arranged in the first slot. This FCMC is composed of slot allocation, frame control information, and the like.
It is transmitted from the 0 side (the roadside apparatus in the normal use state).

An activation channel (hereinafter referred to as ACT)
C) is mainly arranged in the fifth slot which is the last slot. This ACTC is dedicated to the uplink, and is
From the 0 side, data is transmitted only once at first in this slot.

Data transmission / reception between the tester side and the on-vehicle device is performed in the second to fourth slots other than the slots in which FCMC and ACTC are transmitted, but is often performed in the fourth slot. When the fourth slot is used as a message data slot (hereinafter, MDS), a message data channel (hereinafter, MDC) and an ACK channel (hereinafter, ACKC) are arranged. As the MDC, for the downlink, a beacon service table (hereinafter, BST), a set primitive (hereinafter, SE)
T), a release signal, and a vehicle service table (hereinafter, VST) and a get primitive (hereinafter, GET) for uplink. Also, the fourth slot is
A wireless call number channel (hereinafter, WCNC) is arranged for uplink.

FIG. 3 is a diagram showing the format of each channel. FIG. 2A is a diagram showing the format of FCMC. In this figure, a preamble (PR) indicates that subsequent data is valid data, and a unique word (UW1) indicates data for establishing synchronization. It is. In the roadside device attribute information section, attribute information (for example, the number of slots, etc.) of the roadside device is set. By setting the LID transmitted from the vehicle-mounted device side by ACTC in the link address subfields 1 (LID1) to LID8, the vehicle-mounted device side is notified of which slot to communicate with. Error check code CR
C is generated based on a specific generator polynomial for data other than PR and UW1. This FCMC is received and the C calculated based on data other than PR and UW1.
When the RC does not match the transmitted CRC, the FCMC contains an error and is discarded.

FIG. 3B shows the format of the MDC, where PR, UW2 and CRC are the same as in the case of FCMC. The data section includes communication data from the tester (in the case of a BST signal, a SET signal, and a release signal) or communication data from the vehicle-mounted device (VST signal, GET signal).
Signal)) is set.

FIG. 3C is a diagram showing the format of ACKC, where PR, UW2 and CRC are the same as in the case of FCMC. The ACKC has a function of notifying the source of the MDC data whether or not the data of the MDC arranged in the first half of the same slot has been correctly received.
ACK (Ack) if the data is received correctly
A signal is arranged or, if MDC data is not correctly received, a Nack signal is arranged and transmitted. When the MDC data itself is not received, a Nack signal is not transmitted.

FIG. 3D is a diagram showing the format of ACTC, where PR, UW2 and CRC are the same as in FCMC. The data part of this ACKC contains FCMC
And a link address field LID for performing point-to-point communication between the roadside device and the vehicle-mounted device.

FIG. 3E is a diagram showing a format of the WCNC. PR and UW3 are the same as those of the FCMC, but a CRC is not prepared. The WCNC is a number channel as a wireless terminal unique to the on-vehicle device at the time of manufacture, and is transmitted using an uplink slot allocated from the roadside device.

FIG. 4 is a diagram showing a communication frame of the ETC configured as described above and the timing of each channel. FIG. 4A shows the signal timing on the tester 10 side, and FIG. The signal timing on the side of the vehicle-mounted device 20 is shown.

The signal timing of the tester 10 is shown in FIG.
With reference to (a), code a is the first pulse of the communication frame, and code b is the first pulse of the slot. The pulses A and B are generated by, for example, a programmable logic device provided in the main control circuit 12 or the like of the tester 10. The FCMC signal is transmitted and received at the frame first pulse of the code A, the MDC signal, the ACKC signal, and the WCNC signal are transmitted and received at the slot first pulse of the code B, and the ACTC signal is transmitted and received at the last slot first pulse of the code B. Set the hardware.

The vehicle-mounted device 10 generates a UW1 detection pulse of code c when detecting UW1 of FCMC, and generates a slot head pulse indicated by code d in a communication slot specified by the LID of FCMC based on the pulse. This figure 4
(B) shows an example in which ACTC is transmitted at the first pulse of the fifth slot of the first frame, and MDC and ACKC are transmitted and received at the first pulse of the fourth slot of the next frame.

Now, a description will be given of a test of a communication sequence by the ETC vehicle-mounted device tester of the present invention.

This communication sequence test is based on the test conditions of ARIB-TR-T8 (test item for confirming the connectivity of a land mobile station toll road automatic toll collection system) which is an ETC standard. , Onboard equipment 20
The purpose of this is to check whether the product is manufactured correctly. Therefore, if the data transmitted by the tester 10 is received and analyzed, and it can be confirmed that the corresponding data is transmitted to the tester 10, it can be confirmed that the vehicle-mounted device is normally manufactured. Although a function of encrypting data is incorporated in the roadside apparatus for ensuring communication security, the encryption is not checked in the tester 10 of the present invention.

Referring to FIG. 5, the communication sequence is as follows:
It is shown as a flow diagram on the system controller 11, and the progress of the sequence and the judgment result at each stage are
It is configured to be displayed in a form such as color-coded or blinking.

When the communication sequence starts (step S
1) The tester 10 transmits an FCMC signal to the vehicle-mounted device 20 (step S2), and waits for reception of an ACTC signal from the vehicle-mounted device (step S3).

In step S4, it is determined whether an ACTC signal has been received. In this determination, first, UW2 in the ACTC signal is inspected, and if UW2 has been transmitted normally, the ACTC signal is taken as valid. If the data part of the ACTC signal has a specified size (6 bytes) and the CRC determination is OK, the ACTC signal
The reception of the signal is YES, and otherwise the answer is NO. Here, the CRC determination is OK when the CRC calculated based on the received data and the received CRC match.

Waiting for reception of ACTC signal (step S3)
When it is determined that the ACTC signal has been received (step S4), if the determination is NO, the FCMC signal transmission, the ACTC signal reception wait, and the ACTC signal Judgment Steps S1 to S
By repeating Step 3 a plurality of times (for example, about 10 times), YES and NO are finally determined.

If NO is finally determined, the communication sequence does not proceed, so that the sequence is abnormally terminated (step S17), and steps S2 and S3 of the ACTC signal that caused the abnormal termination are displayed. .

Next, if the ACTC reception is YES, the tester 10 transmits a BST signal (step S).
5) It is determined whether an ACKC signal is received (step S6). It is determined whether the ACKC signal has been received. If the BST data arranged in the first half of the same slot is correctly received in the ACKC, the ACK (Ack) signal is arranged and the BST data is correctly received. If not, a Nack signal is arranged, so that the reception of the ACKC signal is determined to be YES with the detection of the Ack signal,
When the Nack signal is detected, A
The reception of the CKC signal is determined as NO. If the BST signal or the ACKC signal itself is not received, it is naturally determined that the answer is NO because no acknowledgment (Ack) signal is detected.

If it is determined that the ACKC signal has been received (step S6), the determination is NO.
Steps S5 and S5 of transmitting the T signal and determining the ACKC signal
By repeating Step 6 a plurality of times (for example, about 10 times), finally, YES and NO are determined.

If it is finally determined that the answer is NO, the sequence is abnormally terminated (step S17), and step S6 of ACKC reception which caused the abnormal termination is displayed.

Next, ACKC reception in step S6 is YE
If it becomes S, the vehicle-mounted device 20 in the next frame
It waits for the reception of a VST signal from (step S7), and determines in step S8 whether a VST signal has been received.

This judgment is almost the same as the ACTC reception in step S4. First, UW2 in the VST signal is checked, and if UW2 is transmitted normally, the VST
Capture the signal as valid. If the data portion of the VST signal has a specified size (67 bytes) and the CRC determination is OK, the reception of the VST signal is YE
S, otherwise NO. Where CRC
The determination is OK if the CRC calculated based on the received data matches the received CRC.

Waiting for reception of a VST signal (step S7) and determination of whether or not a VST signal has been received (step S7)
8), if NO is determined, V
The transmission of the ST signal is instructed to wait for the reception of the VST signal (step S7), and the reception of the VST signal is determined (step S7).
8) or BST transmission (step S5) through V
By repeatedly performing the determination of receiving the ST signal (step S8) a plurality of times (for example, about 10 times), finally,
YES, NO is determined.

If NO is finally determined, the communication sequence does not proceed, so that the sequence is abnormally terminated (step S17), and steps S7 and S8 of the VST signal that caused the abnormal termination are displayed. .

The above processing is applied to the transmission of the SET signal, the reception of the ACKC signal, the waiting for the reception of the GET signal, the determination of the reception of the GET signal in steps S9 to S12, and the processing in steps S13 to S16. The transmission of the release signal, the reception of the ACKC signal, the reception of the WCNC signal, and the determination of the reception of the WCNC signal are sequentially performed in the same manner.

If NO is determined at any stage, the sequence is terminated abnormally (step S17), and the step that caused the abnormal termination is displayed.

When YES is determined in all the steps,
Since the communication sequence has progressed as planned,
The sequence ends normally (step S18).

In the test of the communication sequence, the result of each step of the sequence is displayed on, for example, a block correspondence display screen on the system controller, and the determination result is displayed as “Y
It is displayed as “ES”, “NO”, “OK”, or “NG”.
Accordingly, when there is an abnormality in the communication sequence, it is possible to know at which stage of the sequence the abnormality has occurred, and it is easy to deal with the abnormal termination of the sequence.

Next, a description will be given of a reception sensitivity measurement test using the ETC vehicle-mounted device tester of the present invention.

In ARIB-STD-T55, ET
The receiving sensitivity of the on-board device C is -60.5 dBm to -39.6.
a bit error rate of ^10-5 or less between dBm;
It is defined that there is no response at an incident power of 70.5 dBm or less.

The tester 10 of the present invention has an attenuator 1 as a level control section between the high-frequency section 14 and the output terminal.
5 is provided, and the control of the attenuation is performed by the main control unit 12.
It is performed according to the instruction from. If this attenuator 15 is 0
At the time of dB, the tester 10 outputs a signal of −10 dBm. This attenuator 15 has a maximum of 70 dB.
Since the setting can be made in 1 dB steps, a signal from -10 dBm to -80 dBm can be output from the tester 10 according to the command.

Since the terminal of the tester 10 and the terminal of the vehicle-mounted device 20 are connected by an RF cable, the loss of the RF cable is measured in advance, and the incident power to be input to the vehicle-mounted device 20 can be corrected.

More specifically, in the tester 10 of the present invention, a setting screen is provided in the system controller 11 which is a man-machine interface, and the reception sensitivity upper limit level (-
39.6 dBm) and a predetermined range (−50 dBm to −50 dBm).
10 dBm) can be set, and the receiving sensitivity lower limit level (-
60.5 dBm) and a predetermined range (−65 dBm to −65 dBm).
51 dBm) can be set, and the reception non-response level (−70.5 dBm) is set as a predetermined range (−80 dBm).
~ -66 dBm) can be set. Therefore,
At the time of the receiving sensitivity test of the vehicle-mounted device 20 at each level,
On the setting screen of the system controller 11, the loss due to the RF cable is set as a power correction item,
The level obtained by adding the loss due to the RF cable to the level to be incident on the vehicle-mounted device 20 is set as the output level of the tester 10. As a result, a predetermined level of test power is incident on the vehicle-mounted device 20.

By setting the power levels of various transmission signals from the tester 10 to the upper limit level of the receiving sensitivity, the lower level of the receiving sensitivity, and the no-response level on the setting screen of the system controller 11, the communication sequence test described above is performed. I do.

The description of the communication sequence test itself is omitted since it is as already described. In this reception sensitivity test, when the upper limit of the reception sensitivity is set,
When the lower limit of the receiving sensitivity is set, the communication sequence test determines “good” when the sequence ends normally, and determines “no” when the sequence ends abnormally.
Conversely, when the non-response level of the receiving sensitivity is set, "No" is determined when the sequence ends normally, and "Good" is determined when the sequence ends abnormally.

As described above, by setting the level of the transmission signal from the tester 10 to the vehicle-mounted device 20 to the upper limit, the lower limit, and the no-response level of the reception sensitivity of the vehicle-mounted device by the attenuator 15 as the level control means, the same communication can be performed. The reception sensitivity of the vehicle-mounted device 20 can be tested by the sequence test.

Next, a description will be given of a measurement test of the output level and frequency of the carrier wave transmitted from the vehicle-mounted device 20 by the ETC vehicle-mounted device tester of the present invention. FIG. 6 shows an output signal measurement circuit 18, a main control circuit 12, and a system controller 11 which are directly related to an output level and frequency measurement test for the tester 10 of the present invention.

The output signal measuring circuit 18 includes a mixer 61,
It has a gate 62, an A / D converter 63, and a memory 64. The 5.8 GHz band transmitted from the vehicle-mounted device 20 (accurately: A mode: 5835 MHz, B mode: 584
The signal Rx of 5 MHz) is input to the output signal measuring circuit 18, mixed with the local oscillation signal Lf by the mixer 61, and frequency-converted. The frequency of the local oscillation signal Lf is the signal R
When x is a specified value, 10 MHz from the mixer 61
Is accurately set so that the frequency conversion signal of The gate 62 determines whether or not the signal from the vehicle-mounted device 20 obtained by the main control circuit 12 through, for example, a communication sequence test is normal. When the signal is a normal signal, the gate 62 is turned on by the control signal. In the case of a defective signal, the gate 62 is turned off.

The signal passing through the gate 62 is converted into a digital signal by a sampling signal of a predetermined frequency (for example, 40 MHz) by the A / D converter 63, and the digital sampling data is stored in the memory 64.

The digital sampling data stored in the memory 64 is supplied to the system controller 11 via the main control circuit 12, and calculates an output level and a frequency.

In the frequency calculation, first, after multiplying the sampling data by the Hamming function, FFT (Fast Fourier Transform) is performed to convert the data into frequency data. From the converted frequency data, a frequency having the largest amplitude value is obtained. This is because ASK (amplitude shift keying) is used as an ETC modulation method, and the frequency at which the amplitude value of the converted frequency data is the peak matches the carrier frequency. Use the frequency of

Then, this amplitude value is the peak frequency,
The output frequency Rx of the vehicle-mounted device 20 is accurately obtained based on the frequency of the local oscillation signal Lf used for the frequency conversion.

In the output level calculation, first, an interpolator process is performed on the sampling data to increase the sampling magnification to, for example, eight times. That is, the sampling interval is set to 1/8. Next, the absolute value of the increased sampling data is taken, and only the sampling data corresponding to the logical value 1 is extracted. Where ET
Since the Manchester system is adopted as the C encoding system, a logical value 1 always exists in each symbol. Therefore, sampling data is necessarily extracted for each symbol.

Then, the peak value is extracted from the sampling data of the logical value 1, and the average is taken. This average value is divided by a predetermined value (known power), and its common logarithm is calculated to determine the transmission output level of the vehicle-mounted device 20.

As described above, the test using the tester 10
Based on the measurement, the communication sequence test of the vehicle-mounted device 20, the measurement and test of the output level and frequency of the transmission signal from the vehicle-mounted device 20, the vehicle-mounted device with respect to the transmission upper limit level, the reception lower limit level, and the reception non-response level from the tester 10 20 can be tested without having to change the settings when the OBE is actually communicating.
Measurement can be simplified, time can be reduced, and space can be saved.

[0077]

According to the tester for an on-board ETC device according to the first aspect, it is not necessary to change the setting of the on-board ETC device in the performance measurement test of the on-board ETC device according to the test content, and the on-board device can be actually used. The communication can be easily performed in the communication state, and the required time can be reduced.

According to the second aspect of the present invention, the signal transmission from the tester side to the vehicle-mounted device side and the signal transmission from the vehicle-mounted device side to the tester side are individually determined for each stage. In addition, the communication sequence test can be reliably performed, and when the sequence is abnormally terminated, it can be confirmed at which stage of the vehicle-mounted device or the tester the determination is “No”. Therefore, it is easy to deal with the abnormal termination of the sequence.

According to the third aspect of the present invention, the level of a transmission signal from the tester side to the on-vehicle device is determined by:
The upper limit of the receiving sensitivity of the ETC on-board unit by the level control means,
By setting the lower limit and the no-response level, the reception sensitivity of the on-board ETC device can be tested by the same communication sequence test.

According to the tester for an on-board ETC device according to the fourth aspect, since the signal frequency from the on-board ETC device is converted into a low frequency and then the digital signal processing is performed, the signal processing is easy. In addition, since the transmission / reception signal of the ETC is modulated by the ASK method, it is possible to easily and accurately receive the reception signal by using the fact that the frequency having the largest amplitude value among the frequency data subjected to the FFT processing becomes the carrier frequency. Can be obtained. Also, since the transmission and reception signals of ETC are encoded by the Manchester method,
By using the fact that the logical value "1" is included in each symbol, the level of the received signal can be easily and accurately obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the overall configuration of an on-board ETC tester 10 according to an embodiment of the present invention.

FIG. 2 is a diagram showing a communication frame configuration of ETC.

FIG. 3 is a diagram showing a format of each channel.

FIG. 4 is a diagram showing a communication frame of ETC and timing of each channel.

FIG. 5 is a flowchart of a communication sequence test by the ETC vehicle-mounted device tester of the present invention.

FIG. 6 is a configuration diagram directly related to an output level and frequency measurement test of the tester 10 of the present invention.

FIG. 7 is a schematic diagram of an ETC system configuration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ETC onboard equipment tester 11 System controller 12 Main control circuit 13 Protocol control circuit 14 High frequency part 15 Level control part 16 Transmission / reception switch 17 Divider 18 Output signal measuring circuit 20 ETC onboard equipment 61 Mixer 62 Gate 63 A / D converter 64 Memory

Continuation of the front page (72) Inventor Futa Michishima 5-1-1 Shimorenjaku, Mitaka-shi, Tokyo Inside Japan Radio Co., Ltd. (72) Inventor Kenji 5-1-1 Shimorenjaku, Mitaka-shi, Tokyo Japan Radio Co., Ltd. F term (reference) 3E027 EA01 EC10 5K042 AA06 CA02 CA13 CA23 DA16 EA03 JA05

Claims (4)

[Claims] 1. A communication sequence test for monitoring a progress of a transmission / reception sequence while updating a signal to be transmitted and a signal to be received with an ETC vehicle-mounted device (hereinafter referred to as a vehicle-mounted device) as the transmission / reception sequence progresses. Means, an output signal measuring means for receiving a signal received from the vehicle-mounted device, and measuring a frequency and a level of the received signal; receiving a transmission signal output from the communication sequence test means, and receiving a level according to a level control signal. Level control means for outputting the adjusted transmission signal; receiving the transmission signal from the level control means at the transmission terminal and outputting the signal to the outside; outputting the signal from the outside to the reception terminal; Means and transmission / reception separating means for supplying the output signal measuring means, the communication sequence testing means, the output signal measuring means,
And a main control means for controlling the level control means. 2. The communication sequence test means according to claim 1, wherein
Transmission of a frame control message channel (FCMC) signal from the TC OBE tester side (hereinafter, tester side), reception of an activation channel (ACTC) signal from the OBE side, and corresponding beacon service table from the tester side (BST) signal transmission, receiving a vehicle service table (VST) signal from the vehicle-mounted device side, transmitting a set primitive (SET) signal from the tester side, and a get primitive from the vehicle-mounted device side (GET) signal reception, transmission of a release signal from the tester side to it,
On the other hand, while monitoring the progress of a series of communication sequences of the reception of the wireless call number channel (WCNC) signal from the vehicle-mounted device, whether or not each of the signals transmitted from the tester was correctly received by the vehicle-mounted device. The ACK channel (A
CKC) signal, and the quality of each signal transmitted from the vehicle-mounted device is determined by inspecting the signal. If any of the communication sequences is determined to be "No", the sequence is abnormally terminated. 2. The tester for an on-board ETC device according to claim 1, wherein the sequence is normally terminated when it is judged "good" at any stage. 3. An output level of said level control means is set by said main control means to an upper limit level of reception sensitivity, a lower limit level of reception sensitivity and a non-response level of reception sensitivity of the vehicle-mounted ETC device, and each of said communication sequences Test,
In the case of the upper limit and the lower limit of the receiving sensitivity, "good" is determined when the sequence ends normally, and in the case of the no response level of the receiving sensitivity, "good" is determined when the sequence ends abnormally. 3. A tester for an on-board ETC device according to claim 1. 4. The output signal measuring means receives a signal coded by the Manchester method and modulated by an ASK (amplitude shift keying) method from the vehicle-mounted device, and measures the frequency and level of the received signal. In order to achieve this, the signal frequency from the vehicle-mounted device is mixed with a local oscillation signal by a mixer, converted to a low frequency, converted to a digital signal of a predetermined sampling frequency, and the frequency of the received signal is converted to the digital signal for a predetermined period. An FFT (Fast Fourier Transform) is performed to obtain a frequency having the largest amplitude value. The frequency is obtained from this frequency and the local oscillation signal frequency, and the level of a received signal is converted to the digital data or the digital data obtained by oversampling the digital data. The ETC vehicle according to claim 1, wherein the ETC vehicle is obtained by an average value of peak values of a logical value "1" of an absolute value. Dexterity tester.