JPS6057741B2 - 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 guided wire is shared for 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 guide wires for position detection and the guide wires for data transmission and telephone calls are wired separately to prevent interference with each other, but the drawback is that they are uneconomical and expensive. It was hot. In addition, when data is transmitted between the ground station and the moving object using the separated guiding wire for detecting the position of the moving object as described above, the data signal sent from the ground station may have a phase difference at the division point or junction point of the section. If continuous (in the worst case, the magnetic field phase of both guide wires will be reversed, that is, a difference of 180 o'clock), or if crossed guide wires are used, the magnetic field will become zero due to phase cancellation at the point of intersection, resulting in data transmission. is not performed satisfactorily. The present invention enables data transmission of sufficient quality even in such a case, and the transmission line used for monitoring, controlling, position detection, etc. of a moving object moving on a fixed travel path can also be used for data transmission. This has the effect of economicalization. The present invention will be explained in detail below. FIG. 1 is a diagram illustrating an example of the configuration of a guidance radio device in the case where guide lines for detecting the position of a moving body, which are laid in sections where a traveling route of a moving body is divided into assigned addresses, are shared for data transmission.

A, B, C...... are divided section names, 1 is an electrically independent parallel two-wire induction wire for each section, 2 is its terminating resistor, 3 is a coupler C for each induction wire Various devices a for other purposes are also connected to this. 4, 4b, 4c, and 4d are transmitters (TX) for each guide wire, 5 is a data modulator, and Din is a data signal input terminal.

The above is equipment on the ground station side, but the transmission frequency of the transmitter (TX) is to assign two or more waves of different frequencies alternately or with a certain repetition, but in the case of this figure, 4 , 4c has the frequency Fl, and 4b, 4d have the frequency F2.
is assigned. Also, these transmitters (
TX) has on/off keying (00K) from modulator 5.
), frequency shift (FSK), or phase shift (PSK) modulation input is commonly applied, and thereby the data phases of the plurality of guiding wire currents are synchronized. Next 11-1
Reference numeral 3 designates equipment mounted on a moving object, reference numeral 11 designates a moving receiving antenna All2 connected to the guide wire 1, a receiver (RX), 13 a demodulator (DEM), and DOut a data signal output.
Details of this receiving device will be explained next using FIGS. 2 to 4. FIG. 2 is a block diagram of a configuration example of the demodulator 13 when data is transmitted from the ground station side by FSK modulation, and the output of the receiver 12 is connected to the input.

21 is a bandpass filter (BPF) that passes only the required band of the data signal, 22 is an amplifier, 23 is an amplitude limiter, 24 is a detection or frequency discriminator, and 25 is for band limiting to the fundamental wave of the data signal. low pass filter (LPF)
, 26 are square wave converters using Schmitt circuits or the like.

In this section, the relationship between the waves f1 and F2 transmitted from the ground station will be explained. The optimal frequency difference between f1 and F2 is determined by the modulation method and data transmission speed, but it is important to improve the C/N ratio by bringing the transmission band before the detection L wave on the receiving side closer to the fundamental wave of the data signal. It is necessary to select the difference frequency component of the wave so that it can be sufficiently removed by the filter after detection without damaging the fundamental wave of the data signal. In the case of FSK modulation, if the data transmission rate is, for example, 200 baud, the fundamental wave of the data is 100 Hz, and the cutoff frequency of the LPF after detection is 100 Hz.The value that can sufficiently remove the difference frequency Ifl-F2l is approximately 200 Hz. good. Furthermore, if the deviation frequency Δf of FSK modulation is set to ±200Hz (deviation width is 400Hz), if F2-f1 is selected to 200Hz, f1±
ΔF. f2±Δf are arranged at intervals of 200 Hz. The transmission band before detection is only 200 Hz wider than that obtained by extracting only f1 or F2, and the deterioration of C/N does not cause a large loss in practice. In this way, the ground station maintains the frequency relationship between f1 and F2, and transmits data to each guide line in a phase-synchronized state. FIG. 3 is a characteristic diagram of the frequency discriminator 24 in FIG. 2. When the center frequency is set at the center of f1 and F2 and F2>f1, f1±200Hz is +100H
z and -300Hz1f2±200Hz become +300Hz and -100Hz, and +3 from in-phase data phase
00Hz1+100Hz is output positive (+), -100Hz
and -300Hz output negative (-) outputs, respectively.

Figure 4 shows the mobile receiving antenna 11 from the guide line of each divided section.
In the characteristic diagram of the voltage e induced in
This is the voltage due to the F2 (F2±Δf) wave in the area such as .

These induced voltages are input to a demodulator as shown in FIG.
The detection output corresponding to Δf is input to the next stage LPF 25. However, within a certain range where the mobile antenna approaches or passes through the division point (or junction) of sections A and B, both f1 and F2 are detected, and this difference frequency is 200H.
z is also output from the frequency discriminator 24 according to the input level. Since the fundamental wave of the data signal of 100 Hz or less passes through the LPF 25 and the difference frequency wave is cut off, the Schmitt circuit 26 is driven by an output of only data and restores the square wave data signal to its output. Although the case of FSK modulation has been described above, the same applies to the case where PSK modulation is used. Next, FIG. 5 is a block diagram showing an example of the configuration of the demodulator 13 when data transmission is performed by differential phase shift keying (DPSK).

However, this example is when two-phase DPSK is used, and the frequency difference between the two transmission waves f1 and F2 is n/ when the data transmission rate is 1/T baud, where T is the bit time length of the data signal.
Take T. If n is an integer greater than or equal to 1 and 1/T = 200 baud, the frequency difference is 200Hz when n = 1. ．． 400 for n=2
Hz. In FIG. 5, 41 is a BPF for limiting the band to the required band; 42 is an amplifier; 43 is a limiter; 44 is a circuit for delaying by T time; 45 is a phase discriminator; and 46 is an LP
Fl 47 is a Schmitt circuit, but 46 and 47 may be replaced with integral-discharge filters. Now, the transmitting side (ground station)
Therefore, the data signal is sent out with a 200 Hz difference between Fl and f2, and is input in the order of guide line - antenna -> receiver -> demodulator, and then input to BPF 4l in FIG. Now, if the antenna 11 is located near the center of section A, only the data signal f1 passes through the amplifier 42 and limiter 43, and then passes through the phase discriminator (PD) 45.
input, and at the same time a delay circuit with bit time length T - (D)
The previous bit input after passing through the PD 44 becomes the other input to the PD 45.
The PD discriminates the phase difference between the phase of one bit time before and the current bit phase, and sends the output (for example, an output corresponding to 1 if the phase is in-phase and 0 if the phase is opposite) to the LPF 46.
Then, only the frequency components below the fundamental wave of the data are passed, and a square wave code is output from the square wave converter 47 to restore the data signal on the transmitting side. When the antenna 11 is located near the center of section B, the data signal by F2 is restored in exactly the same manner. In addition, in a state where both f1 and F2 at or near the section dividing point are received, the f1 and F2 waves operate as described above (and the St data are phase-synchronized).
A difference frequency of 200 Hz is output from the PD 45 according to the input level, but it is removed by the LPF 46 and the data signal is correctly restored. As explained above, in the guided wire method shown in Figure 1, by setting the optimum frequency difference for the transmission speed and shift frequency, it is possible to transmit data without reducing the bit error rate even at the section dividing point and its vicinity. It is. 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.

Give the mobile object its unique number in binary code,
The F3 wave is transmitted from a transmitter provided in the mobile body by sharing the antenna 11 or through a separately provided transmitting antenna (the transmitter and transmitting antenna are not shown). The F3 wave has a different frequency from both the f1 and F2 waves that transmit data, and is used as a BPF (bandwidth wave transmitter) 2 of a data reception demodulator mounted on a mobile body.
Modulation with the above unique number outside the bands 1 and 41 (for example, the lower S
K) Leave it. On the other hand, each divided section of the guide line 1 on the ground station side is connected to a receiver F3 (not shown, but included in α in the figure) via a coupler 3.

For example, it includes a demodulator for the above-mentioned 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) that determines the section where the mobile object exists in the ground station and its unique number. Demodulation (detection)
The demodulated output is sent to the mobile body position determiner only when the level exceeds a certain level. This constant level is selected to be less than or equal to 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 object is input only from the receiver in the section where the moving object exists to the mobile object position determiner, and the section where the moving object exists and the unique number of the moving object are detected in this way. can do. 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 crossed 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 is set from bit 1 to There is a configuration method in which the position of the moving body is detected by making intersections at the section division points in accordance with O and utilizing the fact that the phase of the current flowing through the guide wire is reversed before and after the intersection point.

For example, Figure 6 shows an example of the configuration of two of the Gray codes.
The parallel two-wire guide wires 61 and 62 to which the bits are assigned are crossed at the section division points according to the code, and two frequencies F3 and F4 different from the above f1 and F2 are connected to the moving body side.
3 transmitters are installed, and the transmitting antenna 67 coupled to the guide wires 61 and 62 is shared for transmission, or another transmitting antenna is used to transmit the F3 wave and the F4 wave. (F
3. The transmitter and transmitting antenna for f4 are not shown. ) On the other hand, on the ground side, the F3 wave and F4 are taken out from the couplers of the guide wires 61 and 62, thereby making it possible to detect the position of the moving object.

(A mobile object position detection device using such crossed parallel two-wire guide wires is described in Japanese Patent Application No. 52-83 filed by the applicant of the present application.
No. 019 (Japanese Unexamined Patent Publication No. 18569/1983), Patent Application No. 18569/1973
113195 (Japanese Unexamined Patent Application Publication No. 54-47676), etc., it is explained in detail in the specifications, so the outline will be explained below.)
. The F, wave and F4 wave taken out as described above are extracted by a wave generator that separates them.

Among these waves, the F3 wave is multiplied by a doubler and inputted to the next stage phase discriminator as a reference phase wave 2f3. (These combiners, F3 and f4 waveforms, doubler, and phase discriminator are not shown.) If there is a crossover of each guide wire, the F3 wave input will have 180 intersections before and after the intersection point. Although the phase changes, the 2f3 wave obtained by doubling this becomes a continuous phase (this can be easily understood if one considers the case where doubling is performed by, for example, full-wave rectification) and is therefore used as a reference phase. Another phase discriminator
The two inputs are the F4 waves from the wave detector, but since the phase of the F4 waves 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 F4 wave phase discriminator output is obtained for each guide line 61 and 62, a 2-bit code indicating the location of the moving object is obtained. Next, a case will be described in which two guide wires in a plurality of intersecting parallel two-wire guide wire groups used for detecting the position of a moving object are shared for data transmission as described above. FIG. 6 is a configuration diagram of this embodiment, in which the guide wire includes 2n bits of the address code and 2n-1 bits of the address code.
This is a case where two bits, 61 and 62, are used. Although line crossing never occurs at the same position of both bit lines, this can be achieved by using, for example, a Gray code as the address code. 63 and 64 are couplers or guiding wires and f
This is a coupling circuit with each of the 1-wave and F2-wave transmitters 65 and 66, and these transmitters (TX) have a circuit that corresponds to their modulation method.
A data signal Din' is input from a modulator (not shown). 67 and 68 are devices placed on the moving body; 67 is a receiving antenna coupled to the guide wires 61 and 62; and 68 is a receiving device including a receiver and a demodulator.

First, the same data signal (with data phase synchronization) is sent from the ground station transmitter to the guide lines 61 and 62, respectively, using f1 waves and F2 waves that have frequency deviations larger than the data transmission rate (baud). Ru. FIG. 7 is a diagram showing an example of the change characteristics of the voltage e induced in the mobile antenna 67 from each guide wire along the travel path.

As shown in the figure, at the intersection of the guide lines, the coupling loss is 1, and even in the vicinity of 180, the level drops significantly due to the cancellation of the opposite phase, but as mentioned above, the antenna output due to f1 and F2 simultaneously decreases in level. Therefore, the two signals of the f1 wave and F2 wave are simultaneously demodulated in the mobile object and the difference frequency between f1 and F2 (for example, 200Hz
) is removed after detection, the data signal DOut can be restored without interference as in the case of FIG. In the above explanation, the transmitted waves were f1 and F2 for simplicity, but generally it is possible to use multiple waves that have the same difference frequency and are modulated in phase synchronization, and in the case of Fig. 1, each interval Repeat in order 1
In the case of FIG. 6, one frequency is assigned to each guide wire (there are two or more guide wires), and on the receiving side, these multiple waves may be received and demodulated by one receiver.

As explained in detail above, according to the method of the present invention, two or more waves having a frequency difference several times the data transmission rate (baud) and data phase synchronization are used to form a divided form of a mobile object. Data transmission is possible without deterioration in data quality on and near junction points of divided sections of position detection guide wires, and on and near intersections of intersecting position detection guide wires. , a significant economic advantage is obtained in that the guided wire can be shared for position sensing and data transmission.

[Brief explanation of the drawing]

Figure 1 is an example of a circuit configuration in which two guide lines installed in each divided section of a mobile vehicle travel path are used for mobile body position detection and data transmission, and Figure 2 is a diagram of a circuit configuration using FSK (frequency shift) modulation. An example configuration diagram of a mobile (receiving side) demodulator when transmitting data from a ground station. Figure 3 shows an example characteristic of the frequency discriminator in Figure 2. Figure 4 shows the voltage induced in the mobile antenna in Figure 1. 5 is a diagram showing an example of the configuration of a demodulator when data is transmitted using DPSK (differential phase shift) modulation, and FIG. 6 is a diagram showing the number of bits of the address code assigned to each divided section. Figure 7 is an example of a circuit configuration where a circuit is installed in parallel in series and crossed in accordance with the address code, and is used for both mobile object position detection and data transmission. It is a characteristic diagram of ivy change. 1, 61, 62...guiding wire, 3, 63, 64...
...Coupler, 4, 4b, 4c, 4d, 65, 66...
...Transmitter, 5...Modulator, 11,67...
...Receiving antenna, 12...Receiver, 13.
... Demodulator, 21, 41 ... BPFl22
,42...Amplifier, 23,43...Limiter, 24...Frequency discriminator, 25,46...
...LPF126,47...Square wave converter, 44
... Delay circuit, 45 ... Phase discriminator, 6
8...Receiver, demodulator.

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 for transmitting information from the ground side to a moving body by sharing guide line equipment 1 to 3 configured to detect the position of a moving body by extending a wire guide line, the method comprising: Each segment has a data transmission rate of 2 to 3 bauds.
The two frequencies f_1 and f_2, which have twice the frequency difference, are alternately assigned one wave at a time to each adjacent section along the running route, and on the ground side, f_1 or f_2 according to this assignment is applied.
The transmitters 4, 4b, . . . for each section transmit one wave of
The f_1 is modulated by the data signal (Din), and is equipped with a ground-side transmission equipment consisting of a modulator 5 that inputs 4d and a data signal (Din) for information transmission and simultaneously outputs a modulated wave to each of the transmitters. Alternatively, a transmission wave with a frequency of f_2 is simultaneously sent out to each section of the guide wire, and the moving object receives the two frequencies f_1 and f_2 from the receiving antenna 11 mounted on the moving object and inductively coupled to the guide wire and its reception output. A receiver 12 common to the two waves to be extracted and a demodulator 13 common to the two waves to demodulate the modulated wave output from the receiving equipment are provided to receive one wave or two waves from the guide wire to generate the data signal. A data transmission method using guided radio, characterized by obtaining an output (Dout). 2. The parallel two-wire guide wire for detecting the position of a moving object and the ground-side transmission equipment are installed in each divided section of the traveling path of the moving object, and both ends thereof are terminated with a terminating resistor 2 and a coupler 3, respectively. A modulator 5 that modulates a carrier wave by a data signal (Din) to be transmitted from the ground side and a modulator 5 which is provided in each section of the guide line and whose output is inputted, is installed alternately in each adjacent section. The two assigned frequencies f_1 and f_
Transmitters 4, 4 that convert the frequency and amplify the power into one of the two waves and output the modulated transmission wave to the coupler of the guide wire.
4. The data transmission method using guided radio according to claim 1, characterized in that the ground-side transmission equipment consists of the following. 3 When transmitting a data signal by frequency shift keying, the shift frequency Δf is divided into two frequencies f_1 and f_2.
2. The data transmission method using guided radio according to claim 1, wherein the difference frequency is greater than or equal to the difference frequency. 4 When transmitting a data signal by frequency shift keying, the receiving equipment on the receiving side uses the required bandwidth determined by the difference frequency between the two frequencies f_1 and f_2, the shift frequency Δf, and the data transmission rate (Baud). The demodulator includes a filter 21 for extracting the desired band, an amplifier 22 for its output, and an amplitude limiter for limiting the output to a certain level. 23, a frequency discriminator 24 for tuning its modulated wave, a low-pass filter 25 for removing the difference frequency component between the two transmission frequencies in its output, and a square wave converter 26 for its output. A data transmission method using guided radio according to claim 1. 5 When transmitting a data signal by phase shift keying,
The data transmission method using guided radio according to claim 1, characterized in that the difference frequency (Hz) between the two transmission frequencies f_1 and f_2 is twice the data transmission rate (baud). 6 When transmitting a data signal using phase shift keying, the receiving equipment on the receiving side uses a required bandwidth determined by the difference frequency between the two transmission frequencies f_1 and f_2 and the data transmission rate (baud)2. It consists of a frequency sharing antenna 11, a receiver, and demodulators 12 and 13, and the demodulator includes a filter 41 for extracting the required band, an amplifier 42 for its output, and an amplitude limiter 43 for limiting the output of this amplifier to a certain level. , a delay circuit 44 that delays its output by one bit time;
a phase discriminator 45 for discriminating the phase difference between the outputs of the amplitude limiter and the delay circuit; and a low-pass filter 4 for removing the difference frequency component between the two transmission frequencies f_1 and f_2 in the discriminator output.
6. The data transmission method by guided radio according to claim 1, characterized in that the method comprises a square wave converter 47 for the output thereof. 7 Divide a certain travel path of a moving object into arbitrary sections, assign a series of gray codes as address codes to each section in order, and divide the sections into a plurality of parallel two-wire guide lines equal to the number of bits of the address code. Any two guide wires 6 of the guide wire equipment configured to intersect with address codes at points and extend along the travel path to detect the position of a moving object.
1 and 62 and couplers 63 and 64 at their respective ends are shared to transmit information from the ground side to the mobile body. One wave each of two frequencies f_1 and f_2 having a frequency difference of 2 to 3 times the frequency difference of baud) is allocated, and from the ground side, the above-mentioned frequency signal which is simultaneously modulated by the input of the information transmission data signal (Din) is allocated. transmitters 65 and 66 for each of said guide wires transmitting frequency waves of f_1 or f_2;
The two waves f_1 and f_2 modulated by the input data signal (Din) are sent to the two-lead wires 61 and 62, respectively, according to the assignment, and in the moving body, the two waves f_1 and f_2 are placed on the movable body and A receiving antenna 67 that receives the two waves by inductively coupling with the line and the two frequencies f_ in its received output.
1 and f_2 and commonly demodulates the modulated components thereof.
Receive waves and output data signal from ground side (Dout)
A data transmission method using guided radio, characterized by obtaining the following information. 8 The parallel two-wire guide wire and ground-side transmission equipment for detecting the position of a moving object sequentially assign a series of gray codes as address codes to each divided section of the moving path of the moving object, and calculate the number of bits of the address code. A plurality of equal parallel two-wire induction wires were used, and these multiple induction wires were crossed in accordance with the address code at the dividing point of the divided section, and both ends of each induction wire were connected to a terminating resistor and a coupler, respectively. The same data signal (Di
said two frequencies f_1 and f_
8. The data transmission method using guided radio according to claim 7, wherein the ground-side transmission equipment is comprised of a pair of transmitters 65 and 66 that transmit one wave of each wave. 9 When transmitting a data signal using 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 the data signal is transmitted by frequency shift keying, the receiving equipment on the receiving side uses the required bandwidth determined by the difference frequency between the two frequencies f_1 and f_2, the shift frequency Δf, and the data transmission rate (Baud). The demodulator includes a filter 21 for extracting the required bandwidth, an amplifier 22 for its output, and an amplitude limiter for limiting the output to a certain level. 23, a frequency discriminator 24 for demodulating its modulated wave, a low-pass filter 25 for removing the difference frequency component between the two transmission frequencies in its output, and a square wave converter 26 for its output. A data transmission method using guided radio according to claim 7. 11 When transmitting a data signal 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 using phase shift keying, the receiving equipment on the receiving side uses a required bandwidth determined by the difference frequency between the two transmission frequencies f_1 and f_2 and the data transmission rate (baud)2. The demodulator consists of a frequency sharing antenna 67, a receiving section, and a demodulator 68. The demodulator includes a filter 41 for extracting the desired band, an amplifier 42 for the output thereof, an amplitude limiter 43 for limiting the output to a certain level, and an amplitude limiter 43 for limiting the output to a certain level. a delay circuit 44 for delaying by one bit time; a phase discriminator 45 for discriminating the phase difference between the outputs of the amplitude limiter and the delay circuit; and two transmission frequencies f_1 and f_ in the discriminated outputs.
8. The data transmission method using guided radio according to claim 7, characterized in that the method comprises a low-pass filter 46 for removing a difference frequency component between the two and a rectangular converter 47 for its output.