JPS6057740B2 - Data transmission method using guided radio - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data transmission method in which a guiding wire in a guided radio system is shared with communication for other purposes.

A moving object that moves on a fixed travel path (crane, trolley, etc.)
Guided radio systems are used for multi-purpose transmission, such as control of vehicles, information transmission between mobile bodies and fixed ground stations (hereinafter referred to as ground stations), and detection of the position of mobile bodies. .

In order to detect the position of a moving object, it is possible to divide the travel route into multiple sections and use detectors installed in each section, or to detect the position of a moving object using multiple detectors corresponding to the address (binary code, etc.) assigned to each section. A method has been used in which a group of parallel two-wire guide wires is installed at a crossing point, and the phase of the current induced in each guide wire by electromagnetic waves from a moving object is detected. The guiding wire for position detection and the guiding wire for data transmission and telephone calls are wired separately to prevent interference with each other, but the drawback is that it is uneconomical and expensive. be. In addition, when transmitting data between a ground station and a mobile object using a guide wire for detecting the position of a moving object as described above, there is a coupling loss between the antenna or antenna coil of the mobile object and the guide wire at the intersection of the guide wires. 1 in practice, so there is a drawback that data transmission at such a point cannot be performed satisfactorily. The present invention eliminates the above-mentioned drawbacks, and ensures sufficient data transmission quality at all points on the travel path, and also enables monitoring, control, and position detection of moving objects using a common guide line. The features will be explained in detail below. FIG. 1 is a diagram illustrating an example of the configuration of a guided radio device embodying the present invention.

A, B, C... in the figure are the names of divided sections when the traveling route of a moving object is divided into an arbitrary number of sections and an address code is given to each section. The guide wire 1 is laid out and laid along the running route. 2 is the terminating resistor, 3 is the coupler,
4 is a receiving device; 3 and 4 are provided for each section; the output of the receiving device 4 is collected at a ground station 9 through a communication line 10;

5A, 5B, 6, 7, 8 are the equipment on the moving body side, 5A, 5
Both B are antennas.

These antennas move while being coupled to the guide wire 1, and the distance 1 between 5A and 5B is the section length L of the guide wire and the distance between the ends of the guide wire at the dividing point (this is called the dividing point interval)
It is attached to the side surface of the moving body so that the relationship L1×L1 is established with respect to L2. 6 is within the frequency band assigned to the guided radio, and as explained later, the difference in frequency is 2 to 3 times the data transmission rate (Baud) and also different from the frequency F3 for detecting the position of a mobile object. A transmitter (oscillator) with two frequencies f1 and F2, 7 a modulator, and 8 an input terminal for data to be transmitted.

These facilities are also used for detecting the position of a moving object, as described later, and the transmitter 6 is also required to output frequencies other than Fl and f2, but first we will explain its operation only in the case of data transmission. . In the case of data transmission, the mobile transmitter 6
The f1 wave and F2 wave outputs are both modulated in a phase-synchronized state with the input data from the modulator 7 and are supplied to the antenna 5A and the antenna 5B, respectively.

Modulator 7 is a modulator for data transmission, and performs on-off keying (00K), frequency shift keying (FSK), and phase shift keying (00K) according to the input signal from 8.
(PSK), Fl and f2 are modulated using any predetermined method. In addition, a demodulator for these data transmission signals is provided inside the receiver 4 for each section, and the received output is
If this is the case, the signals are combined in parallel and sent to output 11 of another upper station.
Figure 2 is a block diagram of a demodulator configuration example when FSK modulation is used for both Fl and f2 waves, and 21 is a BPF (bandpass filter).
, 22 is an amplifier, 23 is a beam emitter (amplitude limiter), 24 is
is a detector, that is, a frequency discriminator in this case, 25 is an LPF (low pass filter) for removing the difference frequency after detection, and 26 is a frequency discriminator.
is a Schmitt circuit for converting to a square wave. By the way, the two frequency waves Fl and f2 on the data sending side are FSK.
When using , the following relationship exists. If the data transmission speed is now 200 volts, the fundamental wave of data is 100H.
It becomes z. Therefore, the cutoff frequency of LPF25 is set to 100Hz.
If the attenuation characteristics can be selected to give a sufficiently large attenuation at 200Hz, then f1 and F
Since it is sufficient to set the frequency difference of 2 to 200 Hz, if the shift frequency width is set to twice the value of the frequency deviation of 200 Hz, the required bandwidth occupied by f1 and F2 will be minimized. Now, the FSK-modulated f1 wave and F2 wave are received by the receiver 4 in FIG. 1 and input to 21 in FIG. 2. This BPF2l
After being limited to a required band at , it is amplified at 22 , its amplitude is limited at 23 , and then input to a frequency discriminator 24 . FIG. 3 shows the characteristics of this frequency discriminator 24, and the center frequency between Fl and f2 is selected as the center frequency of this discrimination characteristic. At this time, for example, if f1-F2=200Hz, the f1 wave is -100
Hz1+300Hz,. f2 wave is -300Hz1+10
Since 0Hz is a deviation frequency from the above and the data phase is synchronized, the inputs have the same polarity, and the detection outputs of Fl and f2 are combined and the next LPF 25 outputs the fundamental wave of data, but the difference frequency between f1 and F2 components are removed. The data fundamental wave is then converted into a square wave by the Schmitt circuit 26, and restored and output as the same data as on the data transmitting side.
Next, when applying differential phase keying (DPSK) to both the Fl and f2 waves, the frequency difference between fl and F2 is selected to a value of n/T in accordance with the data transmission speed.

In this), T is the reciprocal of the transmission rate (baud), and n is an integer, n/T.
= n x transmission speed (Baud). This is because when an integral-discharge filter is used in the demodulation circuit, the n/T difference frequency output after T time integration becomes zero. ．． Regarding Fig. 1, if a two-phase DPSK modulator is used as the modulator 7, and the transmission rate of the f1 wave and F2 wave modulated from the transmitter 6 is 200 baud, a frequency difference of 200 Hz is selected from the above formula. The same data is sent to antennas 5A and 5B, respectively. This is the area where moving objects exist. (2g)
It is demodulated by an SK demodulator. In Figure 4, 41 is f1
42 is an amplifier, 43 is a beam transmitter, 44 is a delay circuit for delaying 1 bit time, 45
is a phase discriminator (PD), 46 is an LPF (low pass filter),
47 is a square wave converter. The received signal is first BPF4l
After being band-limited at 42 and 43, the signal is amplified and amplitude-limited and input to one input of the PD 45 and the delay circuit 44, respectively, and from 44, the signal delayed by 1 bit time is input to the other side of the PD 45. DPSK in PD45
Since this is a system, the difference in the signal phase of the preceding bit and the signal phase of the succeeding bit is detected bit by bit, and the output is converted into a code corresponding to 0 if the phase is the same, and ml if the phase is reversed, so this output is processed by the LPF 46. The fundamental wave and the difference frequency are separated, and only the fundamental wave is inputted to the rectangular converter 47, and the output thereof is restored with data having the same code as that on the transmitting side. Although the above explanation is for the case where a filter is used, the same effect can be obtained even if the above-mentioned integral-discharge filter is used instead. Now, the receiving side operates as described above, but the transmitting antennas 5A and 5B of the mobile object
Therefore, the interval 1 along the guide line is between the section length L1 of the guide line and the interval L2 between the dividing points! Kur<! Because of this relationship, even if one of the antennas is at the division point, the quality of the restored data will not deteriorate because the other antenna is sufficiently coupled to the guide line.

Furthermore, when both antennas are coupled to the same section of the guide line, the difference frequency between Fl and f2 is removed by a filter after detection, so that the quality of restored data will not deteriorate. Here, one method of detecting the position of a moving object at a ground station using the guide line method shown in FIG. 1 will be explained.

First, give the mobile object its unique number in binary code,
The F3 wave is transmitted from a transmitter provided on the mobile body, either by sharing the antenna 5A or 5B, or through a separately provided transmitting antenna (the transmitter and transmitting antenna are not shown). F3
has a frequency different from the f1 and F2 waves that transmit data, and is modulated with the above-mentioned unique number (for example, FSK ). On the other hand, each divided section of the guide line 1 on the ground station side receives an F3 wave receiver (not shown, but the coupler 3 is shared) via a coupler 3.

For example, it includes a demodulator for the FSK (frequency shift keyed wave) and a reception level detector. ), and the output of each receiver is sent to a mobile object position determiner (not shown) in the ground station that determines the existence zone and unique number of the mobile object, but the reception level detector in each receiver Only when the demodulated (detected) level is above a certain level, the demodulated output is sent to the mobile body position determiner. This constant level is selected to be lower than the lowest value of the receiver detection output in the divided section where the moving object is present. In this way, a signal indicating the unique number of the mobile body is inputted to the mobile body position determiner only from the receiver in the mobile body presence zone, and the mobile body presence zone and unique number can be detected here. As described above, data transmission and position detection of a moving body can be performed by sharing the same guiding wire. Next, a number of sets of intersecting parallel two-wire guide wires equal to the number of bits of the address code assigned to each divided section are continuously laid in parallel along the running route, and each set of guide wires has the number of bits assigned to it. Intersect the interval division points according to the sign of 1 to 0,
There is a configuration method that detects the position of a moving object by utilizing the fact that the phase of the current flowing through the guide wire is reversed before and after the intersection point.

For example, FIG. 5 is a diagram showing an example of its configuration, in which a parallel two-wire guide wire 51 to which one bit of the Gray code is assigned is crossed according to the code at the section division point, and the above-mentioned f1 and F2 are connected to the moving body side. A transmitter with two different frequencies, F3 and F, = 2f3, is provided, and the transmitting antenna 5A or 5B coupled to the guide wire 51 is shared for this transmission, or the F3 wave and F4 wave are transmitted from a separately provided transmitting antenna. do. (F3, f
4 transmitter and transmitting antenna are not shown. ) On the other hand, on the ground side, the F3 wave and the F wave are taken out from the coupler of the guide wire 51, and the position of the moving object is thereby detected by a moving object position detection device parallel to or included in the receiver 53. be able to.

Note that a mobile object position detection device using such intersecting parallel two-wire guide wires is disclosed in Japanese Patent Application Laid-Open No. 54-14 proposed by the present inventor.
Publication No. 766, Japanese Patent Application Laid-open No. 185-1985, Japanese Patent Application Publication No. 1983
Since it has been explained in detail in JP-A No. 4-47676, an outline will be explained below. The F3 wave and F, wave taken out as described above are extracted by a p wave generator which separates them.

Of these, 2f, which is obtained by multiplying the F3 wave by a doubler, is inputted to the next stage phase discriminator as a reference phase wave. These couplers, F3 and f4 waveform generators, doubler, and phase discriminator are not shown. ) If there is a crossover of each guide line, the F3 wave input will have a 180 phase change before and after the intersection, but the 2f3 wave obtained by doubling this will have a continuous phase (doubling is, for example, a full wave). This can be easily understood if we consider the case where rectification is used), so it is used as a reference phase. Another input to the phase discriminator is the F4 wave from the wave detector, but since the phase of the F4 wave also changes by 180 degrees before and after the intersection of the guide lines, the output of the phase discriminator also causes a positive/negative inversion. In this way, since the phase discriminator output of the F4 wave is obtained for each guide line 51, a 1-bit code indicating the location of the moving object is obtained. Next, a case will be described in which one of the plurality of intersecting parallel two-wire guide wires used for detecting the position of a moving body is shared for data transmission as described above. FIG. 5a is a diagram showing the configuration of this embodiment, in which the same symbols as in FIG. 1 have the same functions.

Further, 51 is one of the parallel two-wire intersecting guide wires, 52 is a coupler Cl53 as a receiver (Rx), and 54 is a restored data output terminal (DOut). FIG. 5b shows the change in the coupling between the guide wire 51 and the mobile antenna, that is, the level e of the induced voltage in the guide wire, and the solid line and the broken line are the zero points of the level due to the f1 wave from the antenna 5A and the F2 wave from the antenna 5B, respectively. indicates that there is a distance difference of l. Therefore, in this case as well, the normal interval L of the level or coupling loss
Between ``1 and coupling loss abnormal section L''2 and l, L''2<l<
If I is selected so that L″1 holds true, data transmission will be performed in exactly the same way as in the case of FIG. 1.BRIEF DESCRIPTION OF THE DRAWINGS FIG. The configuration diagram of the frequency shift (FSK) modulated wave demodulator installed in the receiver in Figure 1, Figure 3 is the characteristic diagram of the frequency discriminator in Figure 2, and Figure 4 is the two-phase differential phase keying (DPSK). FIG. 5 is a block diagram of a wave demodulator, and is an explanatory diagram of a data communication method using crossed guiding wires.

A, B, C... Divided sections of the running road, 1, 51.
...Guiding wire, 3,52...Coupler, 4,
53... Receiver, 5A, 5B... Mobile antenna, 6... Transmitter of two frequencies Fl, f2, etc., 7... Data modulator , 9... Ground station equipment, 10... Contact line, 21, 41...
Bandpass filter, 22, 42...Amplifier, 273,
43... Limiter (amplitude limiter), 24... Frequency discriminator, 25, 46... Low pass filter, 26
, 47... Square wave converter, 44... Delay circuit, 45... Phase discriminator.

Claims (1)

[Scope of Claims] 1. A fixed running path of a moving object is divided into a plurality of arbitrary sections, and a parallel 2-way sensor for detecting the moving object position is installed along the running path for each section.
A data transmission method using guided radio in which information is transmitted from a moving body to the ground side by sharing guide wire equipment 1 to 3 configured to detect the position of a moving body by extending a wire guided wire. A pair of antennas (5A and 5B) that are inductively coupled to the guide wire and send out information signal waves are installed on the body so that the mutual antenna spacing 1 along the guide wire is smaller than the section length L_1 of the guide wire equipment. , and is mounted with the dividing point interval set larger than L_2, and the modulator 7 inputs the data signal for information transmission (Din) and outputs a modulated wave, and the output wave is inputted to set the data transmission rate (Baud). It consists of a transmitter 6 that outputs transmission waves of two frequencies (f_1 and f_2) having a frequency difference of 2 to 3 times that of A transmission equipment for allocating and transmitting the information transmission data signal (
The two transmission waves (f_1 and f_2) simultaneously modulated by the antennas (5A and 5B) are sent to the guide wire separately from the two antennas (5A and 5B). The ground side consists of a receiver 4 for each section that commonly receives and demodulates two transmitted waves, and a ground station device 9 that collects the outputs of these receivers and outputs one data signal (Dout). A data transmission method using guided radio, characterized in that receiving equipment is provided to receive and output information from the mobile object. 2 The parallel two-wire guide wire for detecting the position of a moving object is a guide wire 1 that is laid separately for each divided section of the moving object running path, and both ends of the guide wire of each section are connected with a terminating resistor 2 and a coupler 3. 2. The data transmission method using guided radio according to claim 1, wherein a receiver 4 of said ground-side receiving equipment is connected to each of said couplers. 3 When transmitting a data signal by frequency shift keying, the shift frequency Δf is divided into two frequencies (f_1 and f_
2) The data transmission method using guided radio according to claim 1, wherein the difference frequency is higher than or equal to the difference frequency of (2). 4 When transmitting a data signal by frequency shift keying, the receiving equipment on the receiving side uses two transmission frequencies (f_
1 and f_2), a shift frequency Δf, and a data transmission rate (Baud). The demodulator extracts the required bandwidth. Filter 21 and its output amplifier 2
2, and an amplitude limiter 23 that limits its output to a constant level.
, a frequency discriminator 24 that demodulates the modulated wave, a low-pass filter 25 that removes the difference frequency component between two frequencies (f_1 and f_2) in its output, and a square wave converter 2 of its output.
6. A data transmission method using guided radio according to claim 1, characterized in that the method comprises: 5. Claim 1, characterized in that when a data signal is transmitted by phase shift keying, the difference frequency Hz between two transmission frequencies f_1 and f_2 is twice the data transmission rate (Baud). The data transmission method using guided radio described above. 6 When transmitting a data signal by phase shift keying, the receiving equipment on the receiving side uses two transmission frequencies (f_1
and f_2) and a data transmission rate (baud) as the required bandwidth, and the demodulator includes a filter 41 for extracting the required band, and a filter 41 for extracting the required band, and its output. an amplifier 42, an amplitude limiter 43 that limits its output to a constant level, a delay circuit 44 that delays its output by one bit time, and a phase that discriminates the phase difference between the outputs of the amplitude limiter and the delay circuit. a discriminator 45;
Claim 1, characterized in that the device comprises a low-pass filter 46 for removing a difference frequency component between two transmission frequencies (f_1 and f_2) in its output, and a square wave converter 47 for its output. A data transmission method using guided radio. 7. Divide a certain traveling route of a moving object into arbitrary sections, assign a series of gray code address codes to each section consecutively, and divide it into a plurality of parallel two-wire guide lines equal to the number of bits of the address code. Any one guide line of the guide line equipment configured to detect the position of a moving object by extending along the travel route and crossing with address codes according to the section division points is shared. This is a data transmission method using guided radio in which information is transmitted from a moving body to the ground side, and the moving body is equipped with a set of two antennas (5A and 5A and 5B), and the interval 1 between the two antennas along the guide line is defined as a normal section L where the coupling loss between the guide line and the antenna is small and almost constant.
Abnormal section L that is smaller than '_1 and where the coupling loss increases
'_2, and the data signal for information transmission (
The modulator 7 inputs a signal (Din) and outputs a modulated wave, and the modulator 7 inputs the output wave to generate transmission waves of two frequencies (f_1 and f_2) with a frequency difference of 2 to 3 times the data transmission rate (Baud). It consists of a transmitter 6 that outputs, and is equipped with a transmission equipment that allocates and transmits one wave of a different frequency among the transmission waves to each of the two sets of antennas, and transmits the information transmission data signal (Din). The two simultaneously modulated transmission waves (f_1 and f_2) are transmitted to the two antennas (5A and 5A).
A receiver 53 is installed on the ground side to commonly receive and demodulate the two transmitted waves (f_1 and f_2) from the shared guide line. 1. A data transmission method using guided radio, characterized by receiving and outputting a signal (Dout). 8 The parallel two-wire guide wire for detecting the position of a moving object is a system in which a series of gray code address codes are consecutively assigned to each divided section of the moving object's travel path, and a plurality of numbers equal to the number of bits of the address code are assigned to the traveling path. Each of these guide wires is crossed bit by bit according to the address code at the dividing point of the running route, and both ends of each guide wire are terminated with a resistor and a coupler to connect them. 8. A data transmission system using guided radio according to claim 7, characterized in that a ground-side receiver 53 is connected to one of the receivers. 9 When transmitting a data signal by frequency shift keying, the shift frequency Δf is divided into two frequencies f_1 and f_2.
8. The data transmission method using guided radio according to claim 7, wherein the difference frequency is greater than or equal to the difference frequency. 10 When transmitting a data signal by frequency shift keying, the receiver 53 on the receiving side has two transmission frequencies (
f_1 and f_2)), the frequency difference Δf, and the data transmission rate (Baud). The demodulator extracts the required bandwidth. A filter 21, an amplifier 22 for its output, an amplitude limiter 23 for limiting its output to a constant level, a frequency discriminator 24 for demodulating its modulated wave, and a Claim 7, comprising a low-pass filter 25 for removing a difference frequency component and a square wave converter 26 for its output.
The data transmission method using guided radio as described in . 11 When transmitting data signals by phase shift keying, the difference frequency (Hz) between two transmission frequencies f_1 and f_2
8. The method for transmitting data using guided radio according to claim 7, wherein the data transmission rate is twice the data transmission rate (baud). 12 When transmitting a data signal by phase shift keying, the receiver 53 on the receiving side has two transmission frequencies (f
The demodulator includes a receiving section and a demodulator whose required bandwidth is determined by the difference frequency between the frequencies (_1 and f_2) and the data transmission rate (baud), and the demodulator includes a filter 41 for extracting the required band, and a filter 41 for extracting the required band. An output amplifier 42, an amplitude limiter 43 that limits its output to a constant level, a delay circuit 44 that delays its output by 1 bit time, and a phase difference between the outputs of the amplitude limiter and the delay circuit is discriminated. Phase discriminator 45
, a low-pass filter 46 for removing a difference frequency component between two transmission frequencies (f_1 and f_2) in its output, and a square wave converter 47 for its output. The data transmission method using guided radio as described in .