RU2186461C2 - Device for transmitting and receiving signals over radio channel - Google Patents

Abstract

FIELD: radio engineering; burglar alarm systems. SUBSTANCE: device has n controlled stations, common control center, three-phase low-voltage power transmission line, unit for shaping radio signal repetition rates, and transmitting antenna; information in the form of video pulses arrives at information inputs of transmitters at controlled stations wherefrom high-frequency stuffed radio pulses are transmitted to common control center. EFFECT: enhanced transmission speed. 2 dwg

Description

 The invention relates to electrical engineering and can find application for the formation of a radio channel, which is part of a security television alarm system of objects, which can serve as summer cottages, garages, retail outlets, etc., where there is no telephone connection and there are no electric networks that are galvanically connected between the monitored points (KP) and the general dispatching point (DP) along the lines (0.38-10-35) kV. The invention solves the problem of creating a simplex radio channel at the same frequency between the CP and the DP, with only transmitters installed on the CP, and only a receiver on the DP. The transmission of television signals (signals) from the CP is carried out without a request from the DP, while ensuring the specified probability of loss (transformation) of the television signal, which is determined by GOST 16521-74.

 It is known "Device for transmitting and receiving signals through wires of a three-phase power line" (ed. Certificate. 1757110, N 04 B 3/54, 1992). The disadvantage of this device is the low speed of signal transmission and the loss of its operability in the absence of galvanic communication via wires of a three-phase power line with a voltage of (0.38-10-35) kV between the gearbox and the power supply.

 It is also known "Device for transmitting signals through a three-phase low-voltage power line" (patent 2122285, 6 N 04 B 3/54, 1998), which is taken as a prototype. Despite the increase in the transmission speed compared with the previous method, there remains a drawback - the loss of its operability in the absence of galvanic communication via wires of a three-phase power line (0.38-10-35) kV between the gearbox and the power supply.

 In the claimed device, even in the absence of galvanic communication over the wires of a three-phase power line (0.38-10-35) kV between the gearbox and the power supply, the device remains operational.

 "A device for transmitting and receiving signals over a radio channel" in which there are n = 1, 2, 3, ... (n-1), monitored points (KP), a three-phase low-voltage power line 1 (line), a common control room ( DP), while on the CP they have a transmitting unit 2 (transmitter), on the PD have a receiving unit 5 (receiver), a forming unit 3, a transmitting antenna 4 are introduced on the CP, while one of the phases of line 1 is connected to the first input of the transmitter 2 and to the input of the forming unit 3, the output of which is connected to the second input of the transmitter 2, the output of which is connected to the input of the transmitter it has antennas 4, a receiving antenna 6 is introduced on the DP, which is connected to the first input of the receiver 5, the second input of which is connected to one of the phases of line 1.

The block diagram of the device shown in figure 1, where
1. line;
2. transmitter;
3. formation unit;
4. transmitting antenna;
5. receiver;
6. receiving antenna.

где F=50 Гц - частота промышленного напряжения в линии 1 единой энергосистемы, где установлены КП. Радиосигналы передают с каждого КП с разными периодами следования T₁, T₂, Т₃... Т_n, где индексы 1, 2, 3,...n обозначают номера КП. Эти периоды следования радиосигналов образуют в блоках формирования 3. Моменты времени начала передачи сигналов с каждого КП являются моментами времени перехода питающего напряжения частоты F в линии 1 через ноль, при этом все КП установлены в единой энергосистеме, где частота F в любых ее точках одинакова. Радиосигналы передают в двоичном коде с пассивной паузой. Они несут информацию о состоянии коммутационного оборудования, установленного на каждом КП. Эта информация в виде видеоимпульсов приходит на информационные входы передатчиков КП фиг.1, где их заполняют высокой частотой и через передающую антенну 4 радиоимпульсы передают на ДП.The device operates as follows: transmitters 2 on each gearbox continuously transmit radio signals of duration τ

where F = 50 Hz is the frequency of industrial voltage in line 1 of a single power system, where the gearbox is installed. Radio signals are transmitted from each transmission unit with different repetition periods T ₁ , T ₂ , T ₃ ... T _n , where indices 1, 2, 3, ... n denote the numbers of the transmission unit. These periods of the following radio signals form in blocks of formation 3. The moments of the start of the transmission of signals from each KP are the time of the transition of the supply voltage of frequency F in line 1 through zero, while all the KPs are installed in a single power system, where the frequency F at any of its points is the same. Radio signals are transmitted in binary code with a passive pause. They carry information on the status of the switching equipment installed on each gearbox. This information in the form of video pulses arrives at the information inputs of the transmitters of the KP of FIG. 1, where they are filled with high frequency and, through the transmitting antenna 4, the radio pulses are transmitted to the DP.

 At the DP, the high-frequency signals are received by the receiving antenna 6 of the receiver 5. The high-frequency signals are detected in the receivers 5 and receive signals in the form of video pulses of figure 1, which are fed to the information output of the receivers 5 for further processing.

Thus, signals from all CPs will be distributed on the time axis and their coincidence, in the time interval Δt = τ, will correspond to the Poisson probability law, since the following conditions are met (ES Wentzel, Probability Theory. "Science" 1964, M.):
1. The flow of events (signals coming from the CP) is ordinary.

 2. The flow of events is stationary.

 3. The flow of events - has no aftereffect.

 The condition of ordinary means that the signals from each dispersed KP come to the common receiver 5 DP individually, and not in pairs, triples, etc.

The stationarity condition is satisfied by the flow of events, the probabilistic characteristics of which are independent of time. A stationary flow is characterized by a constant flow density λ _cf - the average number of events (signals) arriving at the receiver 5 DP per unit time.

где n - число КП, работающих на один ДП, - постоянная величина;

усредненный период следования событий (сигналов) - постоянная величина.

where n is the number of KP working on one DP, is a constant value;

the averaged period of events (signals) is a constant.

From (1) it follows that λ _cf = const and means the constancy of events (signals) in units. time.

 The condition of absence of aftereffect means that events (signals) enter the system (at the receiver 5 DP) independently of each other.

All these three necessary and sufficient properties are possessed by the flow of events (signals) from dispersed CPs, where the average follow-up period T _cf is constant.

где m= 4 (обоснование будет дано ниже), l - основание натурального логарифма, Р - вероятность совпадения сигналов на интервале времени Δt = τ. В заявленном способе Р - есть вероятность потери (трансформации) сигнала при наложении их друг на друга в приемнике 5 ДП на интервале времени Δt = τ; а - параметр Пуассона, есть математическое ожидание числа сигналов, попадающих на интервал времени Δt = τ.

где λ_ср(t)- средняя плотность потока. В данном случае

Поэтому решение (3) даст
α = λ_срτ (4)
При m=4 выражение (2) примет вид

Ниже мы докажем, что а<<1, т.е. принимаем значение l^a≈1 и, при этом условии, выражение (5) примет вид

Определим а из (6) а

С другой стороны, с учетом (1) и (4) имеют

Выразим (7) и (8) через Т_ср

где n, τ, Р задают в технических условиях.Poisson's law has the form

where m = 4 (justification will be given below), l is the base of the natural logarithm, and P is the probability of coincidence of signals in the time interval Δt = τ. In the claimed method P - there is a probability of loss (transformation) of the signal when superimposed on each other in the receiver 5 DP on the time interval Δt = τ; a is the Poisson parameter, there is a mathematical expectation of the number of signals falling into the time interval Δt = τ.

where λ _cf (t) is the average flux density. In this case

Therefore, solution (3) will give
α = λ _cf τ (4)
For m = 4, expression (2) takes the form

Below we prove that a << 1, i.e. we take the value l ^a ≈1 and, under this condition, expression (5) takes the form

We define a from (6) a

On the other hand, taking into account (1) and (4), they have

We express (7) and (8) in terms of T _cf

where n, τ, P are specified in specifications.

The rationale for the choice of values of the periods of the sequence of signals from each CP
1. Assume that T ₁ = T ₂ = T ₃ = ... = T _n . When superimposing signals from two gearboxes at point 1 of FIG. 2, the receiver 5 DP will not accept these signals. It should be noted that this situation will last as long as you like, until one of the transmitters of one of the control gears is turned off, from which two signals were superimposed.

 2. We will analyze the case when each control unit has its own, different from the others, signal repetition period, as is done in this technical solution.

When superimposing two signals from two gearboxes at point 1 of Figure 2, the receiver 5 DP these signals will not accept. After a period of time T _cf, these signals will diverge due to the difference in the repetition periods. We require that the signals at point 2 from the other two transmitters of the gearbox do not overlap each other, i.e. so that in the time interval Δt = t ₃ -t ₂ (Fig.2) the information on the DP would be received by the receiver 5. If such an overlap does occur, then we require that the probability of such an event would be P = 10 ^-6 , those. corresponded to GOST 16521-74 for the loss (transformation) of the television signal.

Thus, in the time interval Δt = t ₂ -t ₁ at points 1 and 2 (Fig. 1), two coincide pulses from four different KPs are allowed, and the probability of the occurrence of an event of coincidence of two signals at point 2 (Fig. 2) is equal to P = 10 ^-6 . Therefore, in the expression (5), the value m = 4 is taken. As a result of the study of the minimum number of coincidences of signals from n KP with different repetition periods that were multiples of even numbers, odd numbers, primes, it was proved that the most optimal solution is the multiplicity of repetition periods of signals with n KP to primes.

An example of calculating the parameters of the claimed device
Given: 1. N = 100 - the number of dispersed KP working on one DP.

 2. τ = 0.01 s - the duration of the transmission of the radio signal from one KP.

3. P = 10 ^-6 - the probability of getting to point 2 of figure 2 of two signals from different KP.

при τ = 0,01 c и τ_u/= 0,1•10^-3 c можно передать 100 бит информации с каждого КП за время

- Определим из (9) усредненное значение периода следования сигналов с n КП:

В нашем примере Т_cр будет соответствовать периоду следования сигналов с 50-го КП, т.е. равно Т₅₀.4. τ _u = 0.1 • 10 ^-3 - the duration of one radio pulse. The value is selected from the following considerations: By a decision of 11/15/78, the State Committee for Radio Frequencies of the USSR allowed 665 to use frequencies in the range (162.15-168.075) MHz for the development and operation of radio telesignalization. Based on the allowed emission band, which was allocated and equal to ΔF = 20 kHz, the duration of the radio pulse τ _u is equal to

at τ = 0.01 s and τ _{u /} = 0.1 • 10 ^-3 s, it is possible to transmit 100 bits of information from each control unit in time

- Determine from (9) the average value of the period of the signals with n KP:

In our example, T _cp will correspond to the period of the signals from the 50th CP, i.e. equal to T ₅₀ .

где К₅₀ - количество полупериодов, укладывающихся в периоде следования сигналов Т₅₀.- Determine how many half-periods K = 1, 2, 3 ... n of frequency F will fit in the period of following signals T ₅₀ ,

where K ₅₀ - the number of half-periods that fit in the period of following signals T ₅₀ .

 - Let us determine from the table of prime numbers the nearest prime number to the number 1428. Such a prime number is the number 1427.

We accept the adjusted value of K ₅₀ = 1427.

- Определим, с учетом (13), значения периодов следования сигналов, которые будут кратны простым числам для КП от 1, 2, 3... до n из выражения
T_n = K_n•τ (14)
где Т_n - период следования сигналов для n-го КП.- Determine the prime number for each KP its prime number

- Determine, taking into account (13), the values of the periods of the signals that will be multiples of primes for the CP from 1, 2, 3 ... to n from the expression
T _n = K _n • τ (14)
where T _n - the sequence of signals for the n-th CP.

F - частота промышленного напряжения в линии 1, n=1, 2, 3... (n-1).

F is the frequency of the industrial voltage in line 1, n = 1, 2, 3 ... (n-1).

Операцию умножения К_n на τ производят в блоках формирования 3 на КП, т. е. в блоках 3 должны быть, свой для каждого КП, счетчик полупериодов частоты F и умножитель.

The operation of multiplying K _n by τ is performed in the units of formation 3 by the KP, i.e., in blocks 3 there must be, for each KP, a counter of half-periods of frequency F and a multiplier.

 Let us verify the assumptions made above.

Определим значение l^a при а=0,069
l^a=l^0,069=1,07≈1. (18)
Мы доказали, что допущение, принятое нами, было сделано правомерно.When deriving (6), we took the value a << 1 and believed that l ^a ≈1. We determine the real value of a from (7) for the considered example

We determine the value of l ^a at a = 0,069
l ^a = l ^0.069 = 1.07≈1. (18)
We proved that the assumption we made was legitimate.

где

n= 100, τ_u = 0,1•10^-3c, Т_cp=14,28 с - исходные данные, рассматриваемого примера.- Determine the signal transmission speed in the claimed device:

Where

n = 100, τ _u = 0.1 • 10 ^-3 s, T _cp = 14.28 s - the initial data of the considered example.

 Thus, we proved that the goal set by the invention was achieved, while a new technical result was obtained when transmitting tele-signaling signals from a CP to a DP.

 1. At n = 1, 2, 3 ... (n-1) KPs have only transmitters.

 2. On the DP have only a receiver.

 3. It is known that the largest share of the cost of transceiver equipment falls on the receiving part, which is not available on the control unit.

 4. Despite the fact that the KP and DP do not have a two-way channel, the device is able to work when using the same frequency.

 5. Increased signal transmission speed from 100 Baud to 700 Baud.

 6. If the signals from different CPs coincide in the time interval Δt = τ, in the next period of the signals they will disperse, because their repetition periods are multiples of primes.

Claims (1)

 A device for transmitting and receiving signals over a radio channel in which they have n = 1,2,3,. . . , n and controlled points, a common control room, a three-phase low-voltage power line, at the controlled point have a transmitter, at the control room have a receiver, characterized in that a formation unit is introduced at the controlled point, in which the signal transmission periods are formed, the transmitting antenna , while one of the phases of the low voltage power line is connected to the first input of the transmitter and to the input of the forming unit in which the periods of the following radio signals form, the output is It is connected to the second input of the transmitter, the output of which is connected to the input of the transmitting antenna, a receiving antenna is introduced at the general control room, the input of which is connected to the first input of the receiver, the second input of which is connected to one of the phases of the low voltage power line, while the information is in the form of video pulses comes to the information inputs of the transmitters, where they are filled with high frequency and through the transmitting antenna the radio pulses are transmitted to a common control room.

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