JPH0351145B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an information transmission method and an apparatus for implementing the method, and more specifically, on the transmitting side, a carrier wave is amplitude-modulated with a code signal (a rectangular modulated wave). By using an existing transmission system in which the modulated carrier wave is received and demodulated to detect the code signal on the receiving side, it is possible to transmit information independent of the information transmitted by the existing method. The present invention relates to an information transmission method and apparatus.

In the transmission system of an ATC (automatic train control) device or an ATS (automatic train stop) device, it is desired that the type and amount of information transmitted from the ground to the train can be increased. For example, for ATC, it is desirable to increase the types of speed limit information,
Furthermore, it is desired that various types of information independent of ATC (or ATS, hereinafter the same) information can be transmitted.

In ATC, as a method for transmitting other types of information, the carrier wave is modulated with other types of modulated waves, transmitted from the ground, and received and demodulated onboard the vehicle, thereby transmitting the same number of information as the types of modulated waves. kind of
A method of transmitting ATC information is used, but
In this transmission method, the frequency band of the modulated wave used is limited to a relatively narrow range, for example, 10 to 100 Hz, so there are restrictions due to the performance of filters and amplifiers, and the need to avoid noise and safety. To ensure security, there are limits to the types of ATC information that can be transmitted.

There is a case where information independent of ATC information is transmitted from the ground to a vehicle or from the ground to the ground in order to improve the reliability of ATC information. For example, in connection with level crossing control, the type of approaching train is selected, and if the train in question is a train that stops at a station in front of the level crossing, the level crossing is opened, but the train is informed of the stoppage from the ground. It is conceivable to transmit ATC information to stop the train, set the station departure signal to the proceeding position, and send ATC information to the track circuit that includes the level crossing to allow other trains to continue moving. In this case, the ATC information needs to be constantly transmitted for other trains passing through the track circuit, so the train stop information must be independent of the ATC information.

In addition, as information independent from ATC information,
The information includes door opening/closing command information, departure time control information, and in-vehicle guidance broadcast start command information.

In view of the above points, the present invention utilizes an existing transmission system to transmit information independent of the information originally transmitted by the transmission system, thereby making it possible to transmit information that is independent of the information originally transmitted by the transmission system. The purpose is to enable an increase in the type and amount of information that can be transmitted.

In order to achieve the above object, the present invention provides an information transmission apparatus in which a transmitting side modulates the amplitude of a carrier wave with a code signal and transmits the signal, and a receiving side receives and demodulates the modulated carrier wave to detect the code signal. , on the transmitting side, a plurality of pulses of the waveform pulses constituting the carrier wave are specified so that the number or time of pulses inserted between them corresponds to the information to be transmitted, and the positive or negative polarity of the pulses is specified. On the receiving side, among the pulses that make up the received carrier wave, the pulses whose positive or negative polarity output is null are detected, and the number or time of pulses inserted between them is detected. It is designed to extract information based on.

Next, this invention is implemented using a ground vehicle onboard information transmission device that transmits ATC information from the ground to the vehicle by using two pulses for information transmission and using the track circuit as part of the transmission system. , an embodiment in which information independent from ATC information is transmitted will be described based on the drawings.

FIG. 1 schematically shows the configuration of an information transmission device embodying the present invention, in which parts A and B surrounded by dashed lines are newly added configurations according to the present invention, and the remaining parts are ATC. This is an existing configuration for transmitting information from the ground to the vehicle.

Then, in the part excluding A and B, the carrier wave a from the carrier wave oscillator 1 is modulated by the modulating wave b in the form of a square wave from the modulating wave oscillator 2 in the modulator 3,
After the signal is amplified by the amplifier 4, the power is amplified by the first transformer 5, the power amplifier 6, and the second transformer 7, and the signal wave is transmitted to the track circuit 9 through the impedance bond 8. The signal wave is received and demodulated by the ATC receiving circuit 12 after passing through the bandpass filter 11 via the filter 10, and the modulated wave b is detected.
Transmits ATC information to the vehicle. The waveform of the signal wave sent to the track circuit in this case is as shown in FIG. 2c.

Now, according to the present invention, A is a modulation device added to transmit information independent of ATC information using the above-mentioned ATC information transmission system, and a carrier wave a, a modulated wave b, and independent information I are input. An encoder 13 outputs a pair of pulses in the first half of the period of the modulated wave, in which the time width between the pulses is set corresponding to the content of the information I using the pulses constituting the carrier wave. and a switching element 24 which is operated by the output pulse and sets the base voltage of the transistor on one side of the power amplifier 6 to OV.

The main functions of this modulator A are as follows.

(A) As shown in Fig. 3, the first pulse generator is used to nullify the positive or negative output of the carrier wave pulse included in the signal wave c at the guard time t ₁ from the rise of the modulated wave b. outputs a pulse of

(b) Count the number of carrier wave pulses from the time of outputting the first pulse, and when the counted value matches the data converted from input information I, output the positive or negative polarity of the carrier wave pulse included in signal wave c. outputs a second pulse to nullify again.

(c) The switching element 24 is operated by the first and second pulses to set the base voltage of the transistor of the power amplifier 6 to OV.

Note that before the first pulse with no output and after the second pulse, guard times t ₁ and t ₂ are set in consideration of the transient characteristics accompanying the rise and fall of the modulated wave.
will be provided. In this way, the modulator A selects the two pulses before and after the pulses constituting the carrier wave a according to a predetermined principle, makes the output of the positive or negative pole of the pulse null, and sets the pulse between the two pulses. The number of pulses of the carrier wave to be inserted is changed according to the content of the independent information I.

Further, B is a demodulator added to receive information independent from the ATC information from the signal wave c' received from the transmission system using the track circuit, and the carrier wave a received via the band filter 11.
It has the function of detecting the pulses that have no positive or negative output among the pulses that make up the system, measuring the number of pulses inserted between the no-output pulses, and outputting the measured value data. .

Next, an example of a specific configuration of the modulation device A will be described in detail with reference to FIGS. 3 and 4.

The modulated wave b of the transmitter is sent to the guard time creation circuit 1.
4 and is applied to the fall detection circuit 15. The guard time creation circuit 14 includes a one-shot multi-vibrator 14a, an inverter 14b to which its output d is input, and a two-input AND gate 14 to which the output of the inverter and the modulated wave are input.
After inputting the modulated wave b, this guard time creation circuit 14 outputs after a predetermined guard time (guard time) of a predetermined length _t1 determined by the one-shot multi-vibrator 14a has elapsed.
The output e is inputted to the rising edge detection circuit 16 and also inputted to the counter 17 as a count enable signal.

The rising edge detection circuit 16 detects and outputs the rising edge of the output e of the guard time generation circuit after the guard time _t1 has elapsed, and provides the output f to the flip-flop 18 as a set input.

On the other hand, the counter 17 is supplied with pulses constituting the carrier wave a from the transmitting section as clock pulses. Further, the fall detection circuit 15
is output every time the falling edge of modulated wave b is detected,
The output is input to the counter 17 as a clear signal. Therefore, the counter 17 is for counting the constituent pulses of the carrier wave in the first half of each period of the modulated wave b, but since the operation of the counter is unstable at the beginning of the rise of the modulated wave, its operation is stopped. The stable time is removed by the guard time _t1 generated by the guard time creation circuit 14.

The contents C _{1 to} C o of the counter 17 are always fed to a comparator 19, and the comparator compares them with numerical data D ₁ , D ₂ . . . D _o inputted from the outside via the interface circuit 20. be compared.
This data is converted into a counter 17 in the comparator 19 by a known conversion device, which converts information independent of the information transmitted by the existing information transmission device.
It is a format that can be compared with the contents of the file, for example, converted into a binary coded decimal number.

Then, in one period of the modulated wave b, as described above, the flip-flop 18 is set and outputs b immediately after the guard time _t1 has elapsed, and at the same time,
The counter 17 starts counting carrier wave pulses based on the enable signal e, and the counted values are sequentially applied to the comparator 19 and compared with the data D. When the count value matches the data, the comparator 19 outputs and its output g is applied to the flip-flop 18 as a reset input.

The output h of the flip-flop 18 is input to a rise detection circuit 21 and a fall detection circuit 22, respectively. Further, the detection outputs of the rise detection circuit and the fall detection circuit are inputted as operating signals to a grounded switching element 24 via an OR gate 23. This switching element 24 is connected to a power amplifying section (class B push-pull amplifier) 6 that constitutes the transmitting section of the existing transmission device.
is connected to the base side of one of the transistors _Tr1 .

Therefore, when an operating signal is input from the OR gate 23 to the switching element 24, the transistor _Tr1 of the power amplifying section to which this switching element is connected becomes inactive, and the carrier wave included in the signal wave c from the amplifier 5 is inactivated. The positive or negative output of one pulse becomes null.

The polarity of the output of the carrier wave pulse to be "absent" may be either positive or negative, the same polarity, or different polarity. 2 times before and after within half period of modulated wave
Since only one carrier wave pulse is outputted as "no", envelope detection is not affected in ATC information transmission.

Note that in order to eliminate outputs of different polarities for the two pulses, switching elements each operated by the output i of the falling detection circuit 21 and the output j of the falling detection circuit 22 shown in FIG. Depending on the element, the base side voltage of each transistor Tr ₁ and Tr ₂ of the power amplifier 6 may be set to OV.

Thus, in the modulation device 13, in each half period of the modulated wave b input from the modulated wave transmitter 2 to the modulation device A, the flip-flop 18 is set immediately after the guard time _t1 has elapsed, and the counter 17 is set. The flip-flop 18 is reset by the coincidence of the count value of the pulses constituting the carrier wave with the input information I, so that the pulses constituting the carrier wave are Among them, two pulses are selected such that the number of pulses inserted between them corresponds to the information to be transmitted, and modulation is performed in which the positive or negative output of the two pulses is nullified. (The waveform of the signal wave c' in FIG. 2 shows this case.) The signal wave c or c' sent to the receiving side via the track circuit 9 passes only the carrier wave in the demodulator 25. bandpass filter 26 and amplifier 2
The signal is subjected to noise removal and amplification by 7, and then input to the detector 28. The detected output m is input to a guard time generation circuit 29 consisting of a level detector 29a and a delay timer 29b. The guard time t ₂ created in this way has the same purpose as the guard time t ₁ on the transmitting side, and it takes into account that the input level at the beginning of reception may be unstable and that the rise delay of the detector 28 The uncertainty of pulse counting at that time, which will be described later, is avoided by taking transient phenomena such as The guard time generation circuit 29 outputs the signal up to the end of the first half of the period of the modulated wave after the guard time _t2 has elapsed.

Then, the detection output m passes through the resistance attenuator 30,
The signal is input to the comparator 31 and is compared with the carrier wave c' that has passed through the filter. It is not determined whether the non-output component included in the pulse of the input signal that has passed through the filter appears on the positive or negative pole. Therefore, in order to be able to detect any non-output component contained in either the positive or negative pole, the carrier wave c' after passing through the filter is passed through the phase inverter 33, and its output and the detection output m are combined. A comparison is made by another comparator 33, and the outputs p and p' of the two comparators are inputted to a two-input AND gate 35 via an OR gate 34.

The output of the guard time creation circuit 29 is applied to the other input terminal of the AND gate 35. In other words, this AND gate 35 allows only reliable pulses of the carrier wave inputted from the OR gate 34 to pass through after the guard time t ₂ has elapsed and until the end of the half cycle of the modulated wave. The combined output of the OR gate, as shown in FIG. A pulse width verification circuit 36 is provided at a subsequent stage to enable detection of no output based on modulation without being affected by minute periods of no output.

The output g of the pulse width verification circuit is output from the inverter 37.
The signal is then input to a two-input AND gate 38. The output of the guard time generation circuit is delayed by a delay circuit 39 relative to the output from the pulse width verification circuit, and is supplied to the AND gate 38 as another input. The output of the AND gate is then input to the trigger flip-flop 40 as a trigger. In this manner, the trigger flip-flop 40 alternately inverts and outputs logical values of "1" and "0" each time the pulse width verification circuit detects a non-output pulse among the carrier wave component pulses. The output of this flip-flop 40 is connected to another two-input AND gate 41.
is input as a gate signal.

The output pulses p and p' of the comparator are input to this AND gate 41, and the trigger signal is input to the AND gate 41.
While the gate signal is being input from the flip-flop 40, the carrier wave constituent pulse from the comparator is applied to the counter 42.

Therefore, the counter 42 measures the number of pulses inserted between the two pulses before and after the one in which no output was detected, among the pulses of the received carrier wave.

On the other hand, the output o of the guard time creation circuit is
It is input as an enable signal to a number check circuit 43 for detecting the number of non-output pulses, and the trigger of the trigger flip-flop 40 is input as a pulse to be counted. As a result, only when two predetermined non-output pulses are detected in the first half of each period of the modulated wave, the number check circuit 43 outputs the pulses and feeds them into the register 44, giving the enable signal t to the counter. The contents of 42 are taken into register 44.

The output of the guard time generation circuit is also given to the falling edge detection circuit 45, and when the falling edge of the output is detected, that is, at the end of the first half of the period of the modulated wave c, the output of the guard time generation circuit causes the counter 42 to and clears register 44.

The contents of register 44 are transferred to memory 46, and the contents of this memory are restored by decoder 47 to the transmitted information I.

Although the above embodiment describes the case where information is transmitted from the ground to the train via the track circuit, it can also be used for transmitting information from the ground to the ground, or by using a transmission path other than the track circuit. It can also be applied when transmitting data.

In addition, in the above explanation, as a method of carrying information between two pulses before and after among pulses that make up a carrier wave, carrier wave pulses used in existing transmission systems are used to carry information according to the information to be transmitted. This is done by changing the number of pulses, but
This is also possible by changing the time length between the two pulses before and after the pulse in accordance with the information. However, in practice, most of the time settings use pulses with a constant period, so the method of carrying information by changing the time length also does not require the positive or negative output as described in the claims of this specification. It should be understood that this includes cases where the number of pulses varies between pulses.

As described above, according to the information transmission method of the first invention, among the waveform pulses that constitute the carrier wave according to the current transmission method, the output of the positive or negative polarity of two pulses is nullified, and the output between the two pulses is time span or 2
Since information is carried by changing the number of pulses inserted between pulses, information independent of that information can be superimposed and transmitted without affecting the current information transmission. Then, different information can be included in each cycle of the modulated wave. Therefore, it is possible to increase the types and amounts of information that can be transmitted by one transmission system.

Further, according to the second invention, it is possible to easily carry various information by changing the number of pulses inserted between non-output pulses using the pulses constituting the carrier wave, and the rise and rise of the modulated wave can be easily carried. Highly reliable information transmission can be performed by eliminating the influence of transient characteristics associated with the drop.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a schematic configuration of the present invention, FIG. 2 is a time chart showing the waveforms of a carrier wave, a modulated wave, and a signal wave, and FIG. Time chart for explaining the basic concept of carrying information, Part 4
The figure is a block diagram showing an example of a modulation device, FIG. 5 is a time chart showing the waveform of each output in the portion indicated by alphanumeric characters in FIG. Figure 7 is
FIG. 6 is a time chart showing the waveform of each output in the portion indicated by alphanumeric characters. DESCRIPTION OF SYMBOLS 1... Carrier wave oscillator, 2... Modulated wave oscillator, 3... Modulator, 6... Power amplifier, 9... Orbit circuit, 12... Receiving circuit, A... Modulation device, 13... Encoder, 24... Switching element, B... Demodulator, 14, 29... Guard time creation circuit.

Claims (1)

[Claims] 1 (a) On the transmitting side, a carrier wave is amplitude-modulated with a code signal (a rectangular modulated wave) and transmitted, and on the receiving side, the modulated carrier wave is received and demodulated, and the In an existing information transmission device that detects code signals, (b) the transmitting side transmits a plurality of waveform pulses among the waveform pulses that constitute the carrier wave, depending on the number of pulses inserted between them or the time (c) On the receiving side, among the waveform pulses that make up the received carrier wave, By detecting the absence of positive or negative output, measuring the number or time of carrier wave pulses inserted between them, and restoring the above information based on the measured value, (d) Existing An information transmission method, characterized in that, using the transmission system, it is possible to also transmit information independent of the information transmitted by the existing transmission method. 2. The transmitting side is equipped with (a) a transmitter that amplitude-modulates a carrier wave with a modulated wave and transmits it using an amplifier, and (b) after a predetermined guard time has elapsed from the rise of the modulated wave, A guard time creation circuit to output, and the output of the guard time creation circuit are inputted as an enable signal, and the pulse of the carrier wave is inputted to perform an addition operation,
and an encoder comprising a counter that receives the falling edge detection signal of the modulated wave as a clear signal, and a comparator that compares the data of the information to be transmitted with the contents of the counter and outputs an output when they match. and a modulation device including a switching element that is operated based on a rising detection signal of the output of the guard time creation circuit and a rising detection signal of the output of the comparator, and sets the base voltage of a transistor on one side of the amplifier to OV. The receiving side includes (c) a receiver that receives and envelope-detects the amplitude-modulated carrier wave and demodulates it, and (d) a detector that detects the carrier wave and an output of the detector. After inputting and passing the specified guard time,
A guard time creation circuit that outputs based on an input of a predetermined level or higher from the detector, a detection circuit that detects a non-output pulse among the received pulses forming the carrier wave, and a detection output before and after the detection circuit. 1. An information transmission device comprising: a demodulator having a counter that performs an adding operation between the two and counts pulses or time intervals constituting the carrier wave.