SU1233287A1 - Device for detecting pulsed signals - Google Patents

Description

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The invention relates to radio engineering and can be used in devices that receive sigals, which form a regulating impulse sequence,.

The aim of the invention is to improve the protection against noise and impulse noise with a priori known statistical characteristics of impulse signals and interference.

The drawing shows a structural electrical circuit of the device for detecting pulse signals.

The device for detecting pulse signals contains the first filter 1, the second filter 2 with a passband greater than the passband of the first filter, the third amplitude detector 3j the second amplitude detector 4,

the first key 5, the second key 6, the first threshold element 7, the second threshold element 8, the element SH. 9, the first amplitude detector 10, a pulse selector 11 in duration, an integrating filter 12, a third threshold element 13, an inverter 14.

The device for detecting pulse signals operates as follows.

Let the input act, in addition to JQ of useful signals, only noise interference. Then, at the output of the selector 11, a pulse appears mainly at the arrival of a signal, since the duration of the pgum pulse is usually much shorter than the duration of the pulses of the useful signal. Since the frequency of the useful pulses, the duration of the pulses at the output of the selector 11 and the time of the integrating filter 12 are known: s5 is known and the average amplitude is monitored, the third threshold element 13 is set at this amplitude. only the noise and signal amplitude at the output of the integrating filter 13 did not exceed the threshold of the third threshold element 13. As a result, at the output of the third threshold element 13 there is a logical zero. Consequently, the second key 6 is zero, and the first key 5 is open, since the output of the inverter 14 is the logical unit and the signal from the input through the first filter 1, the third amplitude detector 3, the first key 5 goes to the first threshold element 7, where the output is

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making a decision on the presence of noise or signal amplitude. Thus, if there is only noise interference, the device operates as a single-channel filter detector.

Suppose now that at the input, besides the signal, there is a chaotic impulse noise, which is comparable in duration or equal to the duration of useful pulses. The frequency of the pulses at the output of the selector 11 will increase, therefore j will increase and the voltage at the output of the integrated filter 12. The third threshold element 13 is triggered and at its output a logical unit appears that closes the first key 5 and opens the second key 6. The signal from the input through the second filter 2, the second amplitude detector 4, the second key 6 enters the second threshold element 8, which makes a decision about the presence or absence of a signal. The presence of three thresholds is explained by the fact that the second threshold element 8, Making a trehporogovym provides a dynamic range of the receiver portion of rejection, Ko torm most exposed to powerful impulse noise. A synthesis of the signal reception algorithm, which takes into account the a priori known amplitude fluctuations of the useful and interfering impulses, owls, leads to a similar solving scheme.

In fact, the proposed device achieves the effect that could be achieved by rebuilding the constant time (bandwidth) of the first filter 1, but from the point of view of higher signal detection quality characteristics, it is preferable to the device using a tunable filter, since it has a greater efficiency. bone when a signal is detected against a background of chaotic impulse; ;. interference due to the use of a three-way decision circuit and uni ..: ::. REMAIN, since the choice of a filter is made on the basis of the selection of the input: pulses in duration.

The algorithm of operation of the second threshold element 8 can be presented in the form of a table and is not difficult to implement.

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Note. Z, Z, Zj-iTopo levels on the second threshold element 8; and its input signal.

Claims (1)

Invention Formula A pulse signal detection device containing the first filter, whose input is the device input, the OR element, whose output is the device output, the first and second keys, the first and second threshold elements, the inverter, the output of which is connected to the control input of the first of the key, that is, so that, in order to increase the noise immunity with respect to noise and impulse interference with a priori known statistical characteristics of impulse signals and interference, the United Compiled by N. Melnikov. Editor A, Sabo Tehred O. Sopko Proofreader E. Sirohman Order 2783/57 Circulation 624 Subscription VNIIGSh of the USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d, 4/5 . Production and printing company, Uzhgorod, Projecto st., 4 2332874 sequentially, the first amplitude detector, whose input is connected to the device input, a pulse selector for duration, an integrating filter and a third threshold element, the output of which is connected to the control input of the second key and the input of the inverter, connected in series by a second filter, the input of which is connected to the input of the device, and. the second amplitude detector, the output of which is connected to the input of the second key, the third fO amplitude detector, the input and output of which are connected respectively to the output of the first filter and the input of the first key, the input and output of the first threshold element are connected respectively to the output of the first key and the first input of the OR element, the input and output of the second threshold element are respectively connected to the output of the second key and the second input of the OR element, the second threshold element is three-threshold with a ratio of threshold levels, with the signal at its output equal to one, the signal level U at its input satisfies the ner equalities z, or, and zero - otherwise.