RU2103742C1 - Guarding radio system which uses noise-like signals - Google Patents

Abstract

FIELD: radio engineering. SUBSTANCE: device has unit which uses surface-acoustic waves for optimal processing of noise-like signals which have some remarkable characteristics which facilitates their processing. EFFECT: increased effective range, increased stability to noise, decreased level of interference and parasitic emission, decreased vulnerability of system. 5 dwg

Description

 The invention relates to radio engineering and can be used to protect various national economic objects.

 In domestic and foreign practice, various radio engineering devices and security systems are known [1-5].

However, they have disadvantages:
easily vulnerable and accessible to the intruder due to the simplicity of the algorithm for their functioning;
have low noise immunity and a high level of intrinsic interference and spurious emissions;
they do not have tonal-selective properties, allowing to exclude false response of the system;
many of these systems do not meet the requirements of international standardization and certification services.

 The closest in technical essence to the proposed device is selected as a prototype radio security system for pulse-manipulated cipher signals C1], the structural diagram of which is shown in FIG. 3. The transmitting part of this system contains a watchdog unit (SU), which includes an electrophysical transducer (EFP) and a low-noise amplifier (MU), an encoder (W), a pulse-manipulated cipher signal shaper (FIMU) and an RF power amplifier (UM). The receiving part of the system includes a filtering and matching circuit (CC), a strip amplifier (UP), a decoder (DS) and an alarm block (BPS).

 The principle of operation of the prototype is illustrated by the timing diagrams shown in FIG. 4. When the watchdog node SU (Fig. 4a) is activated, the signal from the AFP through the MU includes an encoder (Ш). The latter forms a sequence of rectangular pulses (Fig. 4b), alternating in accordance with the encryption combination set in the encoder. Each protected object has its own encryption combination. The sequence of pulses on the output of W goes to the FIMSHS. FIMPS includes a high-frequency quartz carrier oscillator. At the output of the FIMSS, a pulse-manipulated cipher-radio signal is formed (IMSHS in Fig. 4c), which, after amplification of the amplifier, is radiated into the air.

 The principle of constructing a cipher-radio signal is that the time allotted for transmission is divided into equal intervals of familiarity, each of which corresponds to either "0" or "1".

 If for “1” we take the presence of high-frequency radiation in the antenna of the transmitter, and for “0” for its absence, such an encryption signal will look like a short radio telegraph message.

 On the receiving side, the cipher-radio signal from the ether through the CC, acting as a band-pass filter and a matching device with the antenna, is fed to the input of the unitary enterprise.

 The amplified UE signal is then fed to the DS input, where if its structure coincides with the cryptographic combination structure set in the DS in accordance with the number of the protected object, the trigger signal of the corresponding BPS is generated.

The prototype has disadvantages:
1. Has a limited (up to 1 km) range, associated with the need to comply with the requirements of electromagnetic compatibility of radio systems.

 2. It has a high level of intrinsic interference and spurious emissions due to the relatively high signal power emitted by the air relative to the claimed embodiment and the presence of switching circuits in the system.

 3. It has low noise immunity due to the absence of matched filtering devices in its composition.

4. The working radio signal (IMSHS) is obviously not endowed with the properties
facilitating its processing and isolation from interference. The aim of the invention is:
increase the radius of the system;
increase e noise immunity;
reduction of the level of intrinsic interference and spurious emissions, as well as the degree of vulnerability of the security radio system.

 This goal is achieved by the fact that in the proposed security system as working (useful) signals, instead of the pulse-manipulated cipher signals used in the prototype, cipher-like signals (SHPS) are used, and with me part of the system is a device based on surface acoustic waves (SAWs) for their optimal processing.

Comparison with the prototype analysis shows that the proposed system is characterized by the presence of two essentially new features:
1. The use of ShPS as workers.

 2. The use of surfactant devices as part of the receiving part of the system for optimal processing of SHPS.

The use of SHPS is mainly due to such properties of these signals as [6-8]:
Broadband
high energy secrecy due to the dispersal of energy in a wide frequency band;
high structural secrecy due to the variety of code combinations and types of modulation (manipulation);
the possibility of their selection by shape (signal structure);
the possibility of convolution (compression) of the signal extended in time and frequency into a very narrow pulse in the receiving device due to the good correlation properties of these signals.

 The listed properties make it possible to reduce the degree of vulnerability of the security system at the ShPS.

 The dispersion of energy in a wide frequency band (i.e., low spectral density), as well as the possibility of selecting the SHPS in shape, makes it easy to solve the issue of electromagnetic compatibility of the claimed system with other traditional radio systems.

 For the processing of SHPS in the receiving part of the system, a device based on surface acoustic waves (SAWs) is used for optimal processing (matched filtering).

 The potential capabilities of SAW devices in the implementation of the required functional operations of processing radio signals were manifested due to such remarkable properties of SAWs as their unique “low-speed” (surfactant propagation velocity is about five orders of magnitude lower than the speed of electromagnetic waves), relatively low energy losses when they propagate along the surface of the working sound duct ( crystal), non-dispersion, easy excitability in a wide frequency range (0.01-1 GHz), the ability to control surfactants at any point on the way e propagation and exact correspondence of a temporal signal to a spatial one.

 Surfactant devices have significantly smaller dimensions and weight compared to electromagnetic ones. In addition, they are located on the surface of the crystal - the substrate, which makes them more durable and reliable. The technology of their production is compatible with the technology of manufacturing integrated circuits. This allows you to ensure the identity of the characteristics of devices on surfactants during replication, which eliminates the need for their settings in the manufacturing process.

 In FIG. 1 is a structural diagram of a radio alarm system for noise-like signals (RSO on ShPS). It consists of radio transmitting and receiving parts.

 The radio transmitting part contains a watchdog unit SU, which includes an electrophysical transducer (EFP) - mechanical (MD), acoustic (AD) or photosensors (PD) - and a low-noise selective amplifier (MIU), an encoder (Ш), a noise-like signal conditioner (PShS) ), as well as a power amplifier (PA).

 The receiving part includes a filtering and matching circuit (CC), a band amplifier (UP), a SAW device for optimal processing of a noise-like signal (UEP on a SAW), and an alarm block (BPS).

 Timing diagrams illustrating the principle of operation of the SIR on the ShPS are shown in FIG. 2.

 The system operates as follows. An EFP, for example, a microphone-type acoustic sensor converts an audio signal (penetration noise into an object) into an electric signal. The converted signal (Fig. 2a) is input to the MIU, which simultaneously performs the functions of a spectrum analyzer and a signal amplifier in an audible frequency range. If the spectrum of the input signal contains harmonics corresponding to sound signals characteristic of unauthorized persons entering the protected area or objects, the MIU amplifies them (Fig. 2b) and transfers it to the input of the encoder (III), which uses a pseudo-random sequence generator ( GPSP) [6].

 The sequence of pulses from the output of W is fed to FSPS. The "mechanism" of the formation of the NPS is explained by the timing diagrams shown in FIG. 5 [6 and 7].

 Among the known SHPS, the widest distribution due to the large ensemble, simplicity of formation, and good correlation properties is found in the randomly-phase-manipulated signals (PSFMnS) obtained as a result of phase manipulation of harmonic oscillations of the carrier frequency (Hz) according to the law of pseudorandom sequence (PSP) [6-8] .

The spectral correlation characteristics of such signals have the following features:
a) the peak of the normalized autocorrelation function (ACF) (Fig. 2e) exceeds the lateral emissions (petals) N times, where N is the signal base or the length of the SRP code;
b) the width (duration) of the peak of the ACF T _p > = 2 _c (Fig. 2e), where _c is the duration of the element (symbol) of the SRP;
c) the envelope of the energy spectrum depends little on the SRP code. 90% of the signal energy is concentrated in the main "lobe" of the spectrum.

Owing to such properties, the PSFMnS extended in time (t = N • A _c ) and frequency and “recessed” in noise can be isolated on the receiving side by time compression into a narrow radio pulse T _u = 2 _c (Fig. 2e), concentrating in it about 90% of the total useful signal energy.

Therefore, here we consider the case of the formation of a pseudo-random-phase-manipulated noise-like radio signal using a binary ("0" -) phase manipulator [6], the phase of the carrier wave changing by 180 ^o in which occurs at the time of changing the symbol "1" or "0" (Fig. 5 , 6) in the pseudo-random sequence to the opposite “0” or “1”, respectively (Fig. 5c).

Formed SHPS is amplified by a power amplifier of the PA and is transmitted into the air for 3-5 s (B _p in Fig. 2c).

 At the receiving side of the ШПС through the input filtering and matching circuit (CC) and a band amplifier (UP), it is fed to the SAE on the SAW.

The UEP on the SAW performs optimal processing (time compression) of the NPS, as a result, at the end of the action of the NPS on the air, the correlation peak (Fig. 2e) with a duration of T _p equal to the duration of two characters of the pseudo-random sequence (T _p = 2 B _c ), which contains 90% of the input useful signal energy.

 When the response at the UEP output to the SAW reaches its peak value, a BTS is triggered, reproducing short disturbing tonal sounds alternating with pauses of the same duration (Fig. 2e).

The operation of the proposed security system on noise-like signals showed:
1. The radius of the system when the output power of the transmitter P _o = 1 W is 20-25 km (versus 1 km for the prototype) and can be increased by choosing the parameters of a noise-like radio signal and improving the environmental characteristics of the SAE.

2. The system works without interruptions when the noise at the input of the receiver is in the form of white noise R _w = 250 MW and emissions of various radio stations in the working frequency band with an average power of 40-45 watts. At the same time, the distances from the receiving antenna to these radio stations are 1-5 km.

 3. The level of intrinsic interference and spurious emissions of the system does not exceed 50 MW.

Sources of information
1. Vinogradov Yu. Radio, 1994, N 3, p. thirty.

 2. Ivanov B. Radio, 1993, N 6, p. 37.

 3. Security kit "Outpost-001" Radio. 1994, N 6, p. 36.

 4. Reike C.D. 55 electronic signaling circuits / Per. from English -M .: Energoatomizdat. 1991. c. 112.

 5. Alekseev D. Radio, 1994, N 7, p. 26.

 6. Petrova N.T., Razmakhnin M.K. Communication systems with noise-like signals. -M .: Sov. Radio, 1969.

 7. Dickson P.K. Broadband systems / Per. from English -M.: Communication, 1979. c. 502.

 8. Varakin L.E. Theory of signal systems. -M .: Sov. Radio, 1978, c. 304.

Claims (1)

 A security system for noise-like signals, the transmitting part of which consists of a series-connected sensor of an unauthorized access signal to an object, an encoder, a shaper of a working radio signal and a power amplifier, and the receiving part of the input filtering and matching circuit, a band amplifier and an alarm block connected together in series, characterized in that in the radio system as a working signal a noise-like signal is used, and in the receiving part between the strip amplifier and In addition to the alarm system, a unit for surface acoustic waves is included for optimal processing of a noise-like signal.

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