JPS633790B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an equipment-intensive ground transceiver for amplitude modulated automatic train control (abbreviated as ATC) signals transmitted and received via a track circuit.
This invention relates to an ATC track circuit that uses a signal to invert the phase of a receiver input, and detects a train using the resulting predetermined frequency signal.

transmitted and received via the train track's track circuit
The ATC signal ground equipment detects the presence or absence of an ATC signal due to an axle track short circuit to ensure train detection, and also sets speed limits that are predetermined according to the blockage or opening conditions of the ATC block section.
Its role is to transmit ATC information to the vehicle. Conventional terrestrial receivers select ATC signals corresponding to the set speed limit and transmit them to the rear section. However, with so-called equipment centralized ground equipment where ground equipment for multiple block sections is housed in one equipment room, the block or open status of the multiple sections can be easily known in the same equipment room. ATC information can be changed and transmitted, and the ground receiver only needs to be able to reliably detect trains, eliminating the need for ATC signal selection.
Therefore, in recent years, an ATC track circuit system has been provided that omit the conventional receiving circuit for each ATC signal that selects the signal type and provides a receiving circuit exclusively for train detection using a circuit configuration as shown in Fig. 1. ing.

That is, Fig. 1 is a schematic diagram of the ground equipment in the above ATC track circuit system, showing as an example the case where the speed information type of the ATC signal is set to three stages: low speed LS, medium speed ms, and high speed HS. It consists of a transmitting circuit S shown by , a receiving circuit R dedicated to train detection, and an intermediate circuit M for creating a frequency group, which is a feature of this system. The transmitting circuit S includes an oscillator Fc of a signal carrier wave fc, a low speed signal fl, a medium speed signal fm, and a high speed signal.
respective generators Fl, Fm, Fh and modulators of fh
Ms, amplifier As, etc., and the carrier wave fc is a low-speed relay lR and a medium-speed relay that switch according to the conditions of blocking or opening of the adjacent forward blocking section.
Any of the signal waves fl, fm, fh that is input to the modulator Ms via an operating contact (hereinafter, contacts are indicated by the same symbol as the relay to which they belong) of either mR or high-speed relay hR (none of which are shown). The signal is modulated by the signal, further amplified, and sent to the track circuit power transmission end of the block section IT of the line L.

The intermediate circuit M is a special carrier wave in this method.
The oscillator F ₀ that generates f ₀ , this carrier wave f ₀ , and each of the signal waves fl, fm, and fh of the transmitting circuit S generate (f ₀ +
balanced modulators Ml, Mm, Mh, which generate balanced modulation frequencies of fl), (f ₀ + fm), and (f ₀ + fh), respectively;
a passband filter for each of said modulation frequencies;
It consists of BPl, BPm, BPh, and amplifiers connected to them. This receiving circuit R is a carrier wave
Passband filter for fc and its sideband fc±(fl~fh)
BPFc, input amplifier Ar, detector Dr, balanced demodulator
BDM, carrier f ₀ only passband filter BPF ₀ ,
It consists of a level detector LD, an output amplifier Ap, a rectifier RF, a train detection relay TR, etc.

In short, the ATC track circuit system shown in Fig. 1 has a balanced modulation frequency (f ₀ + fl) obtained by balanced modulating the special carrier wave f ₀ with signal waves fl, fm, and fh, respectively.
Set either (f ₀ + fm) or (f ₀ + fh) to the ATC speed limit condition, i.e., low speed relay lR or medium speed relay.
The ATC signal is introduced into the balanced demodulator BDM of the receiving circuit R through the operating contact of either mR or high-speed relay hR, and is received by the receiving circuit R via the track circuit of the block section IT, and the ATC signal is detected and demodulated. waves,
The modulated wave of the same signal introduced from the intermediate circuit M is suppressed and removed by the balanced demodulator BDM, and only the carrier wave f ₀ is taken out and passed through the filter BPF _0. After the level is detected, it is amplified and rectified to operate the relay TR. This is what I did. Therefore, the relay TR operates by receiving the ATC signal regardless of the type, such as low speed, medium speed, high speed, etc.

However, in the above-mentioned ATC track circuit type ground equipment, although the receiving circuit is simplified, the intermediate circuit M
Because the ground equipment was specially installed, it cannot be said that the ground equipment as a whole was necessarily simplified, and the economic effect was also insufficient.

Therefore, with the aim of omitting the intermediate circuit in the ground equipment shown in Figure 1 and halving the number of relay circuits that have mechanical elements that can cause failures due to poor contact, etc., the receiver The invention of the ATC track circuit, which inverts the phase of the input and detects trains using the resulting frequency signal,
This patent application was filed on the same day under the name of the same inventor as the present invention. The patented invention uses a phase inverter in the receiving circuit and locally introduces the ATC signal into it to extract the carrier wave of the ATC signal received from the orbital circuit.
The system uses the carrier wave current to drive the train detection relay.

Therefore, when a ring modulator/demodulator is used as a phase inverter, and the frequency ratio between the carrier wave and the modulated signal wave is large, the bandwidth between the carrier wave and its sideband frequency becomes narrow, and the sideband frequency is It may be difficult to attenuate the

As a countermeasure to the above-mentioned case, the present invention inverts the phase of a locally specially provided carrier wave using a demodulated wave of the modulated wave signal inputted from the track circuit side to the receiving circuit, and further introduces this waveform from the transmitting circuit. The signal wave is phase-inverted again, and the train detection relay is driven using the current that has passed through a special carrier waveband filter. Therefore, the object of the present invention is the same as the object of the invention of the above-mentioned separate patent application.

Next, embodiments of the present invention will be described with reference to FIG. 2 and the following drawings. FIG. 2 shows one embodiment of the invention.
In the circuit diagram of the ATC ground equipment, the same symbols are used for circuit elements that are considered to be similar to the circuit elements in Figure 1. Comparing FIG. 2 with FIG. 1, the transmitting circuit is substantially the same, but the intermediate circuit M in FIG. 1 is omitted in FIG. Further, the track circuit side input filter BPFc, amplifier Ar, detector Dr, etc. of the receiving circuit are the same as those shown in FIG. 1, but a level detector LD is further provided. On the other hand, an oscillator F ₀ that generates a special carrier wave f ₀ , a first phase inverter PHR ₁ , a second phase inverter PHR ₂ , and a passband filter for the carrier wave f ₀ are separately installed.
A BPF ₀ etc. is provided, and the carrier wave f ₀ is inputted from the track circuit side to the first phase inverter PHR ₁ , which is detected and demodulated, and the level detected ATC signal wave is supplied to the carrier wave.
Perform phase inversion of f ₀ . After the phase of the carrier wave f ₀ which has been inverted and inputted to the second phase inverter PHR ₂ is inverted again by the phase wave introduced from the transmission circuit to the second phase inverter PHR ₂ , the filter BPF ₀ is inverted. Through,
Train detection relay TR with level detection, width increase, and rectification
It drives the. Note that the phase inverter PHR ₁ ,
For example, when a ring modem is used in PHR ₂ , it is a well-known characteristic of the ring modem that the phase of the carrier wave is inverted each time the polarity of the introduced signal wave switches between positive and negative.

Therefore, as shown in chart a of Figure 3A,
The received input from the orbital circuit is, for example, a carrier wave fc modulated by a signal wave fm, and the modulated wave is demodulated, and further passes through a level detector LD, and the signal wave input to the first phase inverter PHR ₁ is synchronized. diagram chart b
The waveform is shown in . Furthermore, if chart c in the same figure is the waveform of the special continuous carrier wave _F0 generated from the oscillator _F0 and input to the first phase inverter _PHR1 , then the waveform of the carrier wave _f0 output from the first phase inverter _PHR1 . As shown in chart d of the figure, each time the polarity of the signal wave of chart b switches to (+) or (-), its phase is inverted and input to the second phase inverter PHR ₂ . Note that the chart d′ is the positive (+) of the inverted phase,
It represents a negative (-) time point. Therefore, if the signal wave introduced from the transmission circuit to the second phase inverter PHR ₂ is the same signal wave fm as the signal wave of chart b, as shown in e of the same figure, each time the polarity of this signal wave is switched, , the phase of the carrier wave f ₀ is inverted again, and the carrier wave f ₀ output from the second phase inverter PHR ₂ returns to the same waveform as the original carrier wave f ₀ as shown in chart f in the same figure, and the filter BPF ₀ is and drives relay TR. This also applies to the other signal waves fl and fh.

FIG. 3B is a time chart illustrating the circuit operation when the carrier wave fc is mixed into the orbit side of the receiving circuit as unmodulated continuous noise. In other words, chart a in Figure B is a carrier wave as unmodulated noise.
fc, therefore there is no signal wave input from the track circuit to be detected and demodulated, and as shown in chart b in Figure B,
The output of the level detector LD does not appear. Also, figure B
The chart c is input to the first phase inverter PHR ₁ as a continuous wave of the same carrier wave f ₀ as the chart c in FIG. 3A.
Chart d in Figure 3B shows that there is no output from the level detector LD and there is no change in the polarity applied to the signal input terminal of the first phase inverter PHR ₁ , in which case the input carrier f ₀ is chart e in figure B
As shown in the figure, the wave of chart c in figure B passes through as it is and is input to the second phase inverter _PHR2 . However, as _shown in chart f in _FIG . The output waveform is as shown in chart g in Figure B, and the positive (+) and negative (-) phase inversion points are as shown in chart d', which are canceled out in the filter BPF ₀ . The output of the level detector LD is attenuated, and the output of the level detector LD does not appear as shown in chart h of the same figure, and the relay TR
to be restored.

Figure 3c is a time chart showing the operating state when the modulated wave signal of the carrier wave fc input from the track circuit and the signal wave introduced from the transmission circuit to the second phase inverter PHR ₂ are different. Chart a of C is the input waveform when the modulated wave of carrier wave fc is used as signal wave fh, chart b is the detected demodulated signal waveform of the waveform of chart a, and chart c is the series of carrier waves f ₀ input to the first phase inverter. The waveform, chart d is the output waveform of the first phase inverter PHR ₁ of the carrier wave f ₀ whose phase is inverted by the signal wave of chart b, chart d' is the positive and negative phase inversion point, and chart e is the output waveform of the carrier wave f 0 whose phase is inverted by the signal wave of chart b. The waveform of the signal wave fl introduced into the phase inverter PHR ₂ , chart f, is the second wave representing the state in which the phase of the wave of chart d is further inverted at the time when the polarity of the signal wave fl is switched.
The output waveform of the phase inverter PHR ₂ , chart f', indicates the point at which its positive and negative phases are inverted. From the cancellation phenomenon of filter BPF ₀ due to repeated phase inversion,
The output attenuates and becomes small as shown in chart g, becoming below the detection level of the level detector LD, and the output disappears, so that the relay TR is restored.

Note that the first phase inverter PHR ₁ described above inverts the phase of the detected demodulated signal input from the orbit circuit, and the second phase inverter PHR ₂ inverts the phase of the signal wave introduced from the transmission circuit. On the contrary, even if the inversion is performed, the operation will be exactly the same.

As mentioned above, only when the same signal wave as the signal wave received from the orbital circuit is supplied from the transmitting circuit to the second phase inverter PHR ₂ of the receiving circuit, the special carrier wave f ₀
The train detection relay TR can be driven by the current. Therefore, in the case of the present invention, the magnitude of the frequency ratio between the carrier wave of the ATC signal and the modulated signal wave, and the width of the bandwidth between the carrier wave and its sideband frequency are irrelevant.

As is clear from the above embodiments, according to the present invention, the intermediate circuit as shown in FIG. 1 can be omitted, so there is a large effect of reducing costs.
Furthermore, since the number of mechanical circuits such as relay contacts can be reduced by half, reliability is improved.

[Brief explanation of the drawing]

Fig. 1 is an example of a conventional equipment-intensive ground equipment for ATC, Fig. 2 is an example of equipment-intensive ground equipment showing an embodiment of the present invention, and Fig. 3 explains the operation of the same equipment. It is a time chart. PHR ₁ : 1st phase inverter, PHR ₂ : 2nd phase inverter, F ₀ : Special carrier wave oscillator, BPF ₀ : Special carrier wave passing filter, TR: Train detection relay, f ₀ : Special carrier wave, fc: Signal carrier wave, fl, fm, fh: Signal wave (modulated wave).

Claims (1)

[Claims] 1. In an equipment-intensive ground transceiver for rectangular amplitude modulated automatic train control signals transmitted and received via a track circuit, two first and second phase inverters having balanced modulation characteristics are connected to the receiving circuit. and a special carrier wave oscillator different from the signal carrier wave,
The phase of the special carrier wave input to the phase inverter is
The polarity of the signal wave received via the orbital circuit and detected and demodulated is inverted, and the phase of the inverted special carrier wave input to the second phase inverter is changed to a signal having the same waveform as the detected and demodulated signal wave. Either the wave is introduced from the transmitting circuit into the second phase inverter and re-inverted, or the order of the first and second phase inverters is reversed and the wave is re-inverted, and the resulting special carrier wave current is used to drive the train. An automatic train control track circuit characterized by detecting.