RU2533447C1 - Radio frequency safety "not" logic element - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: invention refers to high frequency measurement equipment and may be used for creation of special purpose computational structures and creation of critical systems of railway transport control based on them. Device contains a mixer, band pass filters, computers of signal envelope, analogue keys, adders, threshold elements, half adder, "AND" elements.

EFFECT: improving safety of operation due to ensuring element transition to safe state in case of its occurrence on input of signals mixture during short circuit in device.

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Description

The invention relates to high-frequency measuring equipment and can be used to create specialized computing structures and build controllers based on them to create critical railway control systems.

Known devices that perform logical functions when receiving radio frequency signals (RU 2465645 C1 10.27.2012, SU 1251320 A1 08.15.1986, SU 1615878 A1 12.23.1990, US 20070150794 A1 28.06.2007). The disadvantage of these devices is the low security against false alarms.

The element closest to the one proposed in terms of functional features is the one presented in the well-known solution (V. Kichak, Radio frequency and pulse-frequency elements of digital technology / V. M. Kichak, O. O. Semenova. - Monograph Vinnitsya: UNIVERSUM-Vinnitsya, 2008 - 163 s.) The radio frequency logic element “NOT”, which contains a frequency mixer having two inputs, one of which is supplied with a frequency f0 or A1, with f1> f0, and the second with a shift frequency Δt = f1-f0 connected to band pass filters, which in turn are connected to the adder, which allows perform inverse frequency f0 or f1, applied to the device input.

The disadvantage of this device is that as a result of the input of an element of the mixture of frequencies f0 and f1 (when the tracks in the hardware device are short-circuited), the element passes the total signal of these frequencies to the output, which is unacceptable for critical systems such as railway control systems.

The technical result consists in increasing the reliability of the work by ensuring the transition of the element to a safe state in the event of a signal mixture entering the input during a short circuit in the hardware device.

For this, a radio frequency safe logical element NOT containing a mixer is proposed, the output of which is connected to the inputs of the first and second bandpass filters, the outputs of which are connected respectively to the inputs of the first and second signal envelope calculators and information inputs of the first and second analog keys, the outputs of which are connected to the inputs of the second the adder, while the outputs of the first and second calculators of the envelope of the signal are connected respectively to the inputs of the first adder and the inputs of the first and second threshold output elements, the outputs of which are connected respectively to the inputs of the adder modulo two and the first inputs of the first and second elements And, the second inputs of which are connected to the output of the adder modulo two, and the output of the first adder through the third threshold element is connected to the first control inputs of the first and second analog keys, the second control inputs of which are connected respectively with the outputs of the first and second elements I.

Figure 1 presents the structural electrical circuit of a radio frequency safe logical element NOT.

The RF safe logic element does NOT contain mixer 1, first and second bandpass filters 2 and 3, respectively, first and second signal envelope calculators 4 and 5, first and second analog switches 13 and 14, second adder 15, first adder 6, first and second threshold elements 7 and 8, the adder modulo two 10 the first and second elements And 11 and 12, the third threshold element 9.

The order of the logical element is as follows:

Under normal operating conditions, the input information signal with a frequency f0 and amplitude A is fed to the input of mixer 1 together with a shift frequency Δf equal to the difference in frequencies f1 and f0. The resulting signal f0 + Δf and f0-Δf is supplied to the first and second bandpass filters 2 and 3, the transmission frequencies f0 and f1, respectively.

Since a signal with a frequency f0 was applied to the input, the first band-pass filter 2 connected to the first analog key 13 filters out the signal f0-Δf received at the input after mixer 1, and the second band-pass filter 3 selects the frequency f1 and transfers it to the input of the second analog key 14. From the outputs of the first and second bandpass filters 2 and 3, the signal goes to the inputs of the first and second analog switches 13 and 14, respectively, as well as to the first and second signal envelope calculators 4 and 5, respectively, where the envelope of the signals is calculated using pre Fourier.

Next, from the outputs of the first and second signal envelope calculators 4 and 5, the converted signals (the output of the first signal envelope calculator 4 is a zero signal, and the output of the second signal envelope calculator 5 is a signal envelope with amplitude A), the first adder 6 is received, where the signals are added in amplitude , and on the first and second threshold elements 7 and 8, respectively. From the output of the first adder 6, the signal is supplied to the third threshold element 9.

The first, and second, and third threshold elements 7, 8, and 9 function as follows: if a signal with an amplitude greater than the threshold value is input to the element, then a signal corresponding to a logical unit appears at the output, otherwise, to a logical zero. Thus, the output of the second threshold element 8 will be a logical unit, the output of the first threshold element 7 will be a logical zero, and the output of the third logic element 9 will be a logical unit.

The output of the third logic element 9 is connected to the inputs of the first and second analog keys 13 and 14, which have two control inputs, the operation of which is to translate the analog signal if two logical units are present on the control inputs. The outputs of the first and second threshold elements 7 and 8 are connected with an adder modulo two 10, and with the first and second elements And 11 and 12, respectively.

Thus, at the output of the adder modulo two 10, there will be a logical unit, at the output of the first element And 11 - a logical unit, at the output of the second element And 12 - a logical zero. As a result, at the control inputs of the first analog key 13 there will be a logical zero and one, respectively, which will not lead to the transmission of a signal from the first bandpass filter 2 in accordance with the principle of operation of the analog key.

On the contrary, both logical units will be present at the control inputs of the second analog switch 14, and accordingly, a signal with a frequency f1 will be passed on to the second adder 15. As a result of the entire circuit, when a signal with a frequency f0 is applied to the input, we obtain a signal with a frequency f1 at the output. The principle of operation of the circuit when applying a signal with a frequency f1 to the input is similar, but at the output we get a signal with a frequency f0.

In the event of a malfunction: a case of a short circuit in which both frequencies enter the input, the logic element will work as follows: the first and second bandpass filters 2 and 3 will select the frequencies f0 and f1, respectively, and pass them to the input of the first and second analog keys 13 and 14, respectively . From the outputs of the first and second signal envelope calculators 4 and 5, the calculated signal envelopes will be transmitted to the inputs of the first and second threshold elements 7 and 8, respectively, as well as to the input of the first adder 6.

As a result, the logical units are received from the outputs of the first and second threshold elements 7 and 8 to the input of the adder modulo two 10, which, in accordance with the operating conditions of the adder modulo two 10, will yield a logical zero on the output. As a result, the outputs of the first and second elements And 11 and 12 to the inputs of the first and second analog keys 13 and 14, respectively, will receive logical zeros, which will lead to the fact that the signals received at the input of the first and second analog keys 13 and 14 from the first and second bandpass filters 2 and 3, respectively, will not be skipped. As a result, the output of the circuit will be a zero signal, which satisfies the requirements for the elements used in the construction of functional nodes of critical railway systems.

In the event of a break or a zero signal at the input, there will be no signals at the input, and accordingly, there will also be a zero signal at the output.

Claims (1)

An RF safe logic element NOT containing a mixer, the output of which is connected to the inputs of the first and second bandpass filters, the outputs of which are connected respectively to the inputs of the first and second signal envelope calculators and the information inputs of the first and second analog keys, the outputs of which are connected to the inputs of the second adder, the outputs of the first and second signal envelope calculators are connected respectively to the inputs of the first adder and the inputs of the first and second threshold elements, the outputs to which are connected respectively to the inputs of the adder modulo two and the first inputs of the first and second elements And, the second inputs of which are connected to the output of the adder modulo two, and the output of the first adder through the third threshold element is connected to the first control inputs of the first and second analog keys, the second control the inputs of which are connected respectively with the outputs of the first and second elements I.