RU1830633C

RU1830633C - Demodulator of frequency-modulated signals

Info

Publication number: RU1830633C
Application number: SU904788097A
Authority: RU
Inventors: Марина Викторовна Савищева; Сергей Веденеевич Попов; Виктор Андреевич Сивов; Михаил Георгиевич Вяткин
Original assignee: Военная академия им.Ф.Э.Дзержинского
Priority date: 1990-01-30
Filing date: 1990-01-30
Publication date: 1993-07-30

Abstract

Изобретение относитс к радиотехнике и может быть преимущественно использовано в радиотехнических системах приема информации дл демодул ции сигналов частотной телеграфии. Цель изобретени - по- вышение помехоустойчивости при воздействии узкополосных помех в полосе частот полезного сигнала. Устройство содержит полосовые фильтры 1 и-2, детекторы огибающей 3 и 4, блок выбора максимума 5. компараторы 6-9, схемы И 10, 11, 12, 13, 15, 16, 17 и 18, и схемы ИЛИ 14 и 19. Цель достигаетс за счет взаимного сравнени уровней сигналов на выходах детекторов огибающей как между собой, так и с определенным образом выбранными порогами - минимальным и максимальным. 1 ил.The invention relates to radio engineering and can be advantageously used in radio engineering information reception systems for demodulating frequency telegraphy signals. The purpose of the invention is to increase the noise immunity when exposed to narrow-band interference in the frequency band of the useful signal. The device contains band pass filters 1 and-2, envelope detectors 3 and 4, a maximum selection block 5. comparators 6-9, circuits I 10, 11, 12, 13, 15, 16, 17 and 18, and OR circuits 14 and 19. The goal is achieved by comparing the signal levels at the outputs of the envelope detectors, both among themselves and with a certain way of the selected thresholds - minimum and maximum. 1 ill.

Description

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Изобретение относитс к радиотехнике и может быть преимущественно использовано в радиотехнических системах приема информации дл демодул ции сигналов частотой телеграфии.The invention relates to radio engineering and can be advantageously used in radio engineering information reception systems for demodulating signals by telegraphy frequency.

Цель изобретени - повышение помехоустойчивости демодул тора при воздействии узкополосных помех в полосе частот полезного сигнала.The purpose of the invention is to increase the noise immunity of a demodulator when exposed to narrow-band interference in the frequency band of a useful signal.

На чертеже приведена структурна схема демодул тора.The drawing shows a structural diagram of a demodulator.

Демодул тор содержит первый 1 и второй 2 полосовые фильтры, первый 3 и второй 4 детекторы огибающей, блок выбора максимума 5,первый 6, второй 7, третий 8; четвертый 9 компараторы, первую 10, вторую 11, третью 12, четвертую 13, п тую 15, шестую 16, седьмую 17, восьмую 18 схемы И и первую 14 и вторую 19 схемы ИЛИ.The demodulator comprises a first 1 and a second 2 bandpass filters, a first 3 and a second 4 envelope detectors, a maximum selection block 5, a first 6, a second 7, a third 8; fourth 9 comparators, first 10, second 11, third 12, fourth 13, fifth 15, sixth 16, seventh 17, eighth 18 of the AND circuit and the first 14 and second 19 of the OR circuit.

Устройство работает следующим образом .The device operates as follows.

Claims

The input signal is fed to the information input of the demodulator. If there is a signal at one of the frequencies, the corresponding bandpass filter 1 or

2. The first 3 or second 4 envelope detector extracts the envelope of the signal present at the output of the corresponding filter. The extracted envelope signal from the output of the first 3 or second 4 envelope detector is fed to the corresponding inputs of the maximum 5 selection unit and to the first inputs of the first 6 and third 8 or second 7 and fourth 9 comparators. In addition, the second reference voltage of the maximum threshold level is supplied to the second inputs of the first 6 and second 7 comparators, and the first reference voltage of the minimum threshold level is supplied to the second inputs of the third 8 and fourth 9 comparators. The comparators compare the selected envelope of the signal with threshold levels and at their outputs give the result of this comparison when the polling pulse demodulator arrives at the polling input. The result of the comparison with the outputs of the comparators goes to the And circuits, which also receive the result of comparing the envelopes from the output of the maximum selection block 5. The And circuits decode the states of the outputs of the comparators and the maximum selection block. The appearance of the signal at the output of the first OR circuit 14 indicates that the signal of the first channel is received. The appearance of the signal at the output of the second OR circuit 19 indicates that a signal of the second channel has been received. Formula and claim on Demodulator of frequency-manipulated signals containing the first and second

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bandpass filters, the outputs of which are connected to the inputs of the first and second envelope detectors respectively, the outputs of which are connected respectively to the first and second inputs of the maximum selection block, the third input of which is the demodulator polling input, the information input of which is the combined inputs of the first and second bandpass filters, characterized in that, in order to increase the noise immunity when exposed to narrow-band interference in the frequency band of the useful signal, eight AND elements, two OR elements, and four four comparators, the third inputs of which are combined and connected to the third input of the maximum selection block, the first input of which is connected to the first input of the first comparator and the first input of the third comparator, the first output of which is connected to the second input of the third element And,. the first input of the fourth element And and the fourth input of the eighth element And, the output of which is connected to the fourth input of the second element OR, the third input of which is connected to the output of the seventh element And, the first input of which is connected to the second input of the sixth element And, the second input of the first element And, with the first output of the first comparator and the first input of the second AND element, the output of which is connected to the second input of the first OR element, the first input of which is connected to the output of the first AND element, the first input of which is connected to the second the output of the fourth comparator, the first input of which is connected to the output of the second envelope detector and. the first input of the second comparator, the first output of which is connected to the second input of the second element And,. the first input of the third AND element, the second input of the fifth AND element, the first input of the sixth AND element, the output of which is connected to the second input of the second OR element, the first input of which is connected to the output of the fifth AND element, the first input of which is connected to the second output of the third comparator, the second input of which is connected to the second input of the fourth comparator, the first output of which is connected to the second input of the seventh element And, the first input of the eighth element And and: the fourth input of the fourth element And, the second input of which is connected to the second output of the first comparator and the second input of the eighth AND element, the third input of which is connected to the second output of the second comparator and the third input of the fourth AND element, the output of which is connected to the fourth input of the first OR element, the third input of which is connected to the output of the third AND element, the third whose input is connected to the third input of the second element And, the third input of the fifth element And, the fifth input of the eighth element And ;; the second output of the maximum selection block, the first output of which is connected to the third input of the first element And, - the fifth input of the fourth element And,. third entrance

the sixth element And; the third input of the seventh element I. wherein the second input of the first comparator is connected to the second input of the second comparator and is the second reference input of the demodulator, the first reference input of which is the second input of the fourth comparator, and the outputs of the first and second elements OR are the outputs of the demodulators .