JPS633789B2 - - 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 to set predetermined speed limits 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, in so-called centralized equipment type 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, so a combination of these can be used to 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 signal types 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 an example 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 blocking or opening conditions of the adjacent forward blocking section.
Any of the signal waves fl, fm, or fh that is input to the modulator Ms through 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 , further amplified, and sent to the track circuit power transmission end of block section IT of 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. In addition, the 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
It consists of a BDM, a passband filter BPF ₀ for carrier wave f ₀ , a level detector LD, an output amplifier Ap, a rectifier RF, a train detection relay TR, and the like.

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 how it was done. Therefore, relay TR is slow,
Regardless of the type, such as medium speed or high speed, it operates by receiving an ATC signal.

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 is specially installed, it cannot be said that the ground equipment as a whole has necessarily been simplified, and the economic effect is also insufficient.

The present invention is transmitted as stated in the preface.
This is an ATC track circuit system that detects trains using a predetermined frequency signal obtained by inverting the phase of the receiver input using the ATC signal, and the intermediate circuit of the wayside equipment in Figure 1 is omitted. At the same time, the aim is to reduce by half the number of relay circuits that have mechanical elements that can cause failures due to poor contact.

Next, embodiments of the present invention will be described with reference to FIG. 2 and the following drawings.

FIG. 2 is a circuit diagram of an ATC ground equipment showing one embodiment of the present invention, and the same symbols are used for circuit elements that are similar to those in FIG. 1. Comparing FIG. 2 with FIG. 1, the transmitting circuit is almost the same, but the intermediate circuit M in FIG. 1 is omitted in FIG. fl
The pass filter BPFc, input amplifier Ar, etc. of ~fh) are the same as those shown in FIG _. level detector
Consists of LD, output amplifier Ap, rectifier RF, train detection relay TR, etc. The same signal wave sent from the transmitting circuit to the orbital circuit is then introduced into the phase inverter PHR.

In this way, of the two inputs of the phase inverter PHR, the phase of the modulated carrier wave fc input from the orbit circuit changes every time the polarity of the signal wave locally introduced from the transmitter circuit switches between positive and negative. Invert.
This is a well-known characteristic of the ring modulator.

Therefore, as shown in chart a of Figure 3A,
Assuming that the reception input from the track circuit is, for example, a carrier wave fc modulated by a signal wave fl, and the signal wave locally input from the transmission circuit is the same signal wave fl, as shown in chart b of the same figure, At the time when the polarity of the signal wave fl switches from (+) to (-), the signal of chart a is in a space state and there is no carrier wave fc input, and the carrier wave fc is input only when the polarity of the signal wave fl is (+).
is input, so the output of the phase inverter PHR is a signal with the same waveform as the input, as shown in chart c of the same figure, and the output that passes through filter BPFc also has no sideband waves, as shown in chart d of the same figure. The signal has a waveform of only the carrier wave fc, and after its level is detected, it is amplified and rectified to drive the relay TR. This means that the signal wave
The same applies to fm and fh. That is, when the modulated signal received via the track circuit and the local input signal are the same signal wave, the train detection relay TR operates.

FIG. 3B is a time chart illustrating the circuit operation when the carrier wave fc is mixed into the track side input of the receiving circuit as unmodulated continuous noise. That is, chart a in the same figure is a carrier wave fc as noise in an unmodulated state, and chart b in the same figure is a local input signal waveform diagram of the phase inverter PHR, taking the waveform of the signal fm as an example. In this case, the output waveform of the phase inverter PHR is as shown in chart c in the figure, each time the polarity of the signal wave in chart b switches to (+) or (-).
The phase of continuous carrier wave fc is reversed. In addition, the chart
c' represents the positive/negative time point of the inverted phase.
Therefore, the chart c input to the filter BPFc
The carrier wave fc cancels out each other due to phase inversion, and as shown in chart d of the figure, the carrier wave component disappears and its output does not appear.

In addition, Fig. 3c is a time chart showing a case where the modulation signal of the carrier wave fc and the local signal introduced into the phase inverter PHR are different, and chart a in the same figure shows the modulation wave of the carrier wave fc by the signal wave fl, Chart b in the same figure
is a signal waveform diagram in which the local signal is fh, and chart c in the figure is the output waveform of a phase inverter PHR that inverts the phase of carrier wave fc when the polarity of signal wave fh is switched. In this case as well, the component of the carrier wave fc is canceled due to phase inversion, and as shown in chart d in the same figure, the output from the filter BPFc becomes a small value corresponding to the uncancelled portion of the carrier wave fc, and the output from the level detector LD is Not done.

As mentioned above, the carrier wave received from the orbital circuit
A signal wave with the same waveform as the fc modulation wave is used as a phase inverter.
Train detection relay TR can only be driven when locally supplied to PHR. Therefore, when the input from the track circuit is cut off due to a train short circuit, even if a waveform other than that transmitted as noise is mixed in from the outside, the output will not appear due to the characteristics of the phase inverter, so the relay TR will be restored. , train detection can be performed.

As is clear from the above embodiments, according to the present invention, the intermediate circuit as shown in FIG. 1 can be omitted, so the cost reduction effect is significant.
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: Phase inverter, BPFc: Carrier wave and its sideband passing filter, BPFc ₀ : Passing filter for carrier wave only, TR: Train detection relay, fc: Carrier wave, fl,
fm, fh: signal wave (modulated wave), IT: track circuit (ATC block section).

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, a phase inverter having balanced modulation characteristics is inserted into the receiving circuit, and the phase inverter is connected to the track circuit. A modulated signal received through a circuit is input, a signal wave identical to the modulated wave of the modulated signal is introduced from a transmitting circuit, and a carrier wave of the modulated signal whose phase is inverted by the polarity change of this signal wave is extracted. , an automatic train control track circuit characterized by detecting trains using extracted carrier wave current.