SU792604A1

SU792604A1 - Device for detecting broad-band pulse noise

Info

Publication number: SU792604A1
Application number: SU782562320A
Authority: SU
Inventors: Александр Самойлович Альтман; Вячеслав Дмитриевич Беляков; Лев Александрович Краснов; Владимир Александрович Морозов; Игорь Васильевич Пахомов; Юлий Борисович Синдлер
Original assignee: Предприятие П/Я В-2645; Институт Радиотехники И Электроники Ан Ссср
Priority date: 1978-01-02
Filing date: 1978-01-02
Publication date: 1980-12-30

Description

(54) УСТРОЙСТВО ДЛЯ ОБНАРУЖЕНИЯ ШИЮКОПОЛОСНЫХ ИМПУЛЬСНЫХ ПОМЕХ(54) DEVICE FOR DETECTION OF STYLEBAND PULSE INTERFERENCE

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Изобретение относттс к области радиотехшоси , в частности, к области контрол за уровнем помех в радиоканале при приеме частотно-манипулированных (ЧМ) сигналов в услови х действи помехн, представл ющей собой смесь широкополосного шума и импульсной помехи, обладающей приближе шо равномерным спектром в полосе пропускани входных цепей приемника.The invention relates to the field of radio technology, in particular, to the field of controlling the level of interference in a radio channel when receiving frequency-manipulated (FM) signals in terms of interference, which is a mixture of broadband noise and impulse noise, which has a closer spectrum in the bandwidth receiver input circuits.

Известно устройство обнаружени liMnynbcных помех в присутствии полезного ЧМ сигнала , содержащее последовательно включенные канальный полосовой фильтр, амплитудный ограничитель, частотный демодул тор, фильтр верхних частот и пороговый элемент 1.A device for detecting liMnynbc interference in the presence of a useful FM signal is known, comprising a series-connected channel band-pass filter, amplitude limiter, frequency demodulator, high-pass filter and threshold element 1.

Однако это устройство не обеспечивает необходимую надежность обнаружени импульсных помех при широком диапазоне изменени спектральной плотности действующей импульсной помехи.However, this device does not provide the necessary reliability for detecting impulse noise with a wide range of variations in the spectral density of the active impulse noise.

Целью изобретени вл етс повьииение надежности обнаружени импульсных помех при широком диапазоне изменени интенсивностей действующих сигналов и помех.The aim of the invention is to increase the reliability of the detection of impulse noise with a wide range of variations in the intensities of existing signals and interference.

Поставленна цель достигаетс тем, что в устройство дл обнаружени широкополосных импульсных помех, содержащее канальньш полосовой фильтр, ограничитель амплитудь и частотный демодул тор, к выходу частотного демодул тора подключены последовательно соединенные нелинейный зпемент с характеристикой вида f(x) О при и f(x)0 при 9, причем )Е| , где Е - надр же1ше на выходе частотного The goal is achieved by the fact that a device for detecting broadband impulse noise containing a channel bandpass filter, an amplitude limiter and a frequency demodulator is connected to the output of the frequency demodulator in series with a f (x) O characteristic with and f (x) 0 at 9, moreover) E | where E is the frequency gap at the output

-10 демодул тора, соответствующее частотам на граищах полосы пропускани канального фильтра, Н временной решающий блок. Кроме того, временной решающий блок выполнен в виде последовательно соединенных -10 demodulator corresponding to the frequencies in the bandwidth of the channel filter, H is the time solver unit. In addition, the time decision block is made in the form of series-connected

15 временного дискриминатора и компаратора напр жений.15 temporary discriminator and voltage comparator.

На чертеже приведена структурна блоксхема устройства дл обнаружени широкополосных импульсных помех.The drawing shows a structural block scheme of a device for detecting broadband impulse noise.

2020

Claims

A device for detecting broadband impulse noise contains a channel bandpass filter 1, a limiter 2, a frequency demodulator 3, a non-linear element 4, and a time critical unit 5 consisting of a time discriminator 6 and a voltage comparator 7. The device for detecting wide-band impulse noise is as follows in a way. Let the mixture of the useful FM signal, broadband noise and powerful (Up Uc, where Un, DC are the level of the impulse noise and the useful signal at the output of the channel band filter) pulse interference with an approximately equal spectrum in the bandwidth of the channel acts on the input of the channel bandpass filter 1 foot filter. Under the action of an interference pulse, an oscillatory transient occurs at the output of the channel bandpass filter 1, its frequency (filling frequency) is approximately equal to the average frequency of channel filler 1, and the amplitude over time (/ n (it is determined both by the parameters of the channel filter and the intensity ratio of the useful signal and impulse noise) significantly exceeds the amplitude of the useful signal. As a result, during the time interval Dn the instantaneous frequency of the oscillations at the input of the frequency demodulator 3 will be The fact that the frequency of the channel filter 1 corresponds to a voltage at its output equal to zero. In this case, the voltage at the output of nonlinear element 4 is different from zero. A nonlinear element 4 becomes different from zero when the frequency of the FM signal is changed, as well as due to the effect of noise interference during signal fading. The operation of the proposed device is based on the fact that the duration of the time interval during which the instantaneous frequency of the voltage at the input of frequency demodulator 3 is approximately equal to the average frequency of channel filter 1, when exposed to a powerful impulse noise, significantly exceeds the duration of this time interval in the absence of interference pulses. This circumstance makes it possible, by comparing the duration of 4 signals acting at the output of nonlinear element 4, with a certain predetermined value, to reliably fix the fact i of the presence of impulse noise. The increase in the reliability of the detection of impulse noise in a wide range of their intensity in the proposed device is achieved due to the fact that with an increase in the intensity of the active impulse noise the duration of the interval Tp increases, which leads to an increase in the reliability of the correct detection of the disturbance. In addition, under fading conditions, the likelihood of false detection of impulse noise can be ensured significantly less than in the prototype, all other conditions being equal, due to the fact that in the assumed device with deep fading of the signal, the probability of false detection of impulse interference is approximately proportional to the ratio / E and can be made sufficiently small by the appropriate choice of the value o. Claim 1. A device for detecting broadband impulse noise containing a channel bandpass filter, an amplitude limiter and a frequency demodulator, characterized in that, in order to increase the reliability of the detected impulse noise in a wide range of intensity variation of existing signals and interference, to the output of the frequency demodulator are connected. serially connected nonlinear element with a characteristic of the form f (x) O at and f (x) f 0 at | x | (Y, and. IE /, where E is the output voltage of the frequency demodulator corresponding to the frequencies at the bandwidth limits channel filter, and a time decision block.

2. The device according to claim 1, in which the temporary decision block is designed as a series-connected time discriminator and voltage comparator. Sources of information taken into account during the examination 1. US Patent No. 3783387, cl. 325/348, published. 1974 (prototype).