JPH033036Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a frequency detection device that detects a control signal of a frequency corresponding to control information by digital arithmetic processing.

A specific example of such a frequency detection device is a receiving device for ATC (Automatic Train Control.) signals in railways.
A carrier wave is used that is modulated with a control signal of a frequency corresponding to the control information, which is demodulated in the receiving device, and the control signal is detected according to the frequency, and the vehicle is controlled according to this detection power. The operation status is controlled.

That is, for example, the frequency of the control signal is determined to be 10Hz when the traveling speed is 100km/H, 15Hz when the traveling speed is 30km/H, and 35Hz when the vehicle is stopped.
ATC with carrier modulated by any of these
While the signal is transmitted via the rail, it is received by a loop coil antenna installed on the vehicle.
After demodulating this, the different frequencies are detected using a wave device or the like, and the vehicle's progress is automatically controlled according to the detected power.

However, since the detection frequency is low and a large inductance and large capacity capacitor are required to configure a wave transmitter, in recent years, a processing section that performs digital arithmetic processing such as a small computer has been used to perform this processing. A detection device has been proposed that detects a frequency by performing a Fourier analysis calculation using the following method.

However, in such a processing section, analog
A digital converter converts the control signal into a digital signal, and then performs arithmetic processing based on a predetermined program.If a failure occurs in the processing section, the failure situation is unspecified, and the failure may occur. This has the disadvantage that it is not possible to obtain a fail-safe property such as stopping the vehicle whenever the vehicle is stopped.

The purpose of the present invention is to eliminate such drawbacks of the conventional technology at once, by mixing a control signal and a control signal with a different frequency to the control signal and then feeding it to the processing section, so that the processing section can always detect the reference signal. shall occur,
The object of the present invention is to provide an extremely effective frequency detection device that detects a failure in a processing section by the disappearance of this frequency.

Hereinafter, details of the present invention will be explained with reference to figures showing embodiments.

Figure 1 is a block diagram when the present invention is applied to an ATC signal receiving device, and the antenna ANT
The ATC signal received by is demodulated by the demodulator DEM and becomes a control signal of a specific frequency.
It is applied to an analog-to-digital converter (hereinafter referred to as ADC) A/D via a mixer MIX, where it is converted into a digital signal, and then applied to a processing unit PRS using a small computer, where it is converted into a Fourier signal. The analysis is performed by digital arithmetic processing, and outputs are generated according to frequency, and each output is given to registers RG ₁ to _{RG 4} and held there.

The held output of each register RG ₁ to _{RG 4} is output from a digital-to-analog converter (hereinafter referred to as DAC) D/A ₁ to
Amplified detector AD ₁ ~ which is converted to an analog signal by D/A ₄ and has a threshold level set
By AD ₄ , it becomes a direct current, which drives the relays 10R, 15R, 35R and RR provided correspondingly to these, and closes these contacts 10R ₁ , 15R ₁ , 35R ₁ , thereby increasing the detection force D ₁ ~ D ₃ is sent out, and the contact is activated depending on the recovery of relay RR.
It closes RR ₁ and sends out the detection force _DR .

However, since there is a signal generator RSG that generates a reference signal with a frequency different from each frequency of the control signal, and the output of this is given to the mixer MIX, the control signal and reference signal are mixed here. In addition, it is given to the processing unit PRS, and as long as the processing unit PRS is normal, the output corresponding to the reference signal is given to the register RG ₄ .
The detection power D _R is sent only when a failure occurs in the processing unit PRS.

In other words, since the reference signal is simultaneously processed in the processing unit PRS along with the received control signal, the processing unit PRS
It can be determined whether or not it is normal.

Therefore, by monitoring the detection force D _R , it is possible to determine whether there is an abnormality in the processing unit PRS, and if the vehicle is controlled to stop, etc. in response to the output of the detection force D _R , it is possible to completely It is possible to obtain a fail-safe property.

FIG. 2 is a diagram showing the spectral distribution of the control signals f ₁ to f ₃ and the reference signal f _R. As shown in _FIG .
The reference signal f _R may be set to a frequency different from that of the control signals f ₁ to _{f 3} corresponding to D ₃ , but the noise components N ₁ , N ₂
etc. are also mixed in, so even when these influence the frequencies of the control signals f ₁ to f ₃ and the reference signal f _R ,
For the purpose of making it possible to discriminate between the signals f ₁ - f ₃ and f _R , the level L of each signal f ₁ - f ₃ and f _R is set higher than the level L of the noise components N ₁ and N ₂ , etc. Amplified detector AD ₁ ~
The determination may be made based on the AD ₄ threshold level. In other words, by adding a verification signal to the software and hardware in the processing unit PRS, the same processing unit PRS is verified from both the control signal and the verification signal, and the operation of the processing unit PRS is ensured. It will be inspected.

FIG. 3 is a block diagram showing another embodiment, in which the configuration of the antenna ANT to the amplification detectors AD ₁ to _{AD 4} is the same as that in FIG. In addition to the CT, there is also an verification unit AUT configured with a relay circuit. In this case, the control unit CT controls a signal generator RSG using a voltage controlled oscillator etc. in response to clock pulses from the processing unit PRS. death,
Processing unit A processing unit that changes the frequency of the reference signal in synchronization with the operation of the PRS and follows each frequency condition.
It is designed to dynamically check the operation of the PRS.

In this case, the frequency of the reference signal is determined in advance, and the output corresponding to this is output to the register.
The operating status of the processing unit PRS is set as being sent to RG ₄ .

In addition, in the test unit AUT, control signals f ₁ to _{f 3}
and the relays 10R, 15 corresponding to the reference signal f _R
R, 35R, RR contacts 10R ₁ to 10R ₃ , 15
R ₁ to 15R ₃ , 35R ₁ to 35R ₃ , RR ₁ to RR ₃ indicate that relay RR is in operation and relays 10R and 1
It forms an alternative circuit in which only one of the detection forces D ₁ to _{D 3} is sent out only when only one of 5R and 35R is in operation, and contacts 10R ₄ to 10R ₆ , 15R ₄ ~ 15R ₆ , 35R ₄ ~ 3
From 5R ₆ and RR ₄ , when relay RR is operating and only one of relays 10R, 15R, and 35R is operating, it constitutes a circuit that operates relay SR, and when relay SR is restored, this contact point
When SR ₁ is closed, a detection force D _R indicating the occurrence of an abnormality is sent out.

Therefore, according to the configuration shown in FIG.
Analysis operations over the entire range of input frequencies in the PRS can be checked cyclically, and the detection powers D ₁ to D ₃ and _DR can be obtained only under accurate conditions.

However, as long as the frequency of the reference signal is different from the frequency of the control signal, a direct current or modulated signal may be used, and a mixer MIX may be provided on the input side of the demodulator DEM, or a mixer MIX may be used. The same effect can be obtained by converting the reference signal into a digital signal using a digital adder, etc., and mixing it on the output side of the ADC/A/D. Alternatively, the present invention can be modified in various ways, such as providing a multiplexer between the outputs of the registers RG ₁ to _{RG 4} and the input sides of the amplified detectors AD ₁ to _{AD 4} to share the DAC.

As is clear from the above explanation, according to the present invention, it is possible to always reliably monitor whether the frequency detection device is normal or not using digital arithmetic processing, so it is possible to provide fail-safe properties to the frequency detection device and to receive ATC signals. It can be applied not only to devices but also to frequency detection devices for various purposes, and great effects can be obtained.

[Brief explanation of drawings]

Figure 1 is a block diagram showing an embodiment of the present invention, Figure 2 is a diagram showing the spectrum distribution of each signal, and Figure 3 is a diagram showing the spectral distribution of each signal.
The figure is a block diagram showing another embodiment. PRS...processing section, MIX...mixer, RSG...
Signal generator, RG ₁ ~ RG ₄ ...Register, AD ₁ ~
AD ₄ ...Amplified detector, 10R, 15R, 35R,
RR, SR...Relay, _D1 to _D3 , D _R ...Detection power.

Claims (1)

[Scope of utility model registration request] A frequency detection device including a processing unit that detects a control signal with a frequency corresponding to control information by digital arithmetic processing, comprising: a signal generator that generates a reference signal with a frequency different from that of the control signal; and a mixer for mixing and supplying the mixture to the processing section, and means for processing the control signal and the control signal by the processing section and checking the processing section based on the detection result of the control signal. Characteristic frequency detection device.