SU853567A1

SU853567A1 - Fm reflectometer

Info

Publication number: SU853567A1
Application number: SU792771592A
Authority: SU
Inventors: Михаил Максимович Власов
Original assignee: Предприятие П/Я В-2489
Priority date: 1979-05-28
Filing date: 1979-05-28
Publication date: 1981-08-07

Description

Изобретение относится к радиоизмерительной технике.The invention relates to a radio engineering.

Известен ЧМ-рефлектометр, содержащий последовательно соединенные свипгенератор и смеситель падающей и отраженной от исследуемого сверхвысокочастотного тракта волн, а также блок формирования сигнала весовой обработки, перестраиваемый фильтр и индикатор О]· Однако известный ЧМ-рефлектометр имеет низкую точность и разрушающую способность по длине измерения структу-j ры исследуемого сверхвысокочастотного тракта и его отдельных элементов.A known FM reflectometer containing a series-connected sweep generator and a mixer for the incident and reflected microwave wave path, as well as a weight processing signal generating unit, a tunable filter and O indicator] · However, the known FM reflectometer has low accuracy and destructive structure -j ry of the investigated microwave path and its individual elements.

Цель изобретения - повышение точ- ₎₅ности и разрешающей способности по длине измерения структуры исследуемого сверхвыеокочастотного тракта и его отдельных элементов.The purpose of the invention - an increase _{accuracy) 5} NOSTA and resolution for measuring the length of the test structure sverhvyeokochastotnogo tract and its individual elements.

Для этого в ЧМ-рефлектометре, содержащем последовательно соединенные свипгенератор и смеситель падающей и отраженной от исследуемого сверхвысокочастотного тракта волн, а также блок формирования сигнала весовой обработки, перестраиваемый фильтр и индикатор, к 'выходу смесителя последовательно подключены введенный перемножитель сигналов,- перестраиваемый фильтр и введенный делитель сигналов, вход и выход которого через введенный и первый переключатель соединены с входом индикатора, к другому.входу индикатора подключен второй введенный переключатель, механически связанный с , первым переключателем и подключенный соответственно к второму выходу перестраиваемого фильтра и второму выходу свип-генератора; блок формирования сигнала весовой обработки выполнен в виде формирователя импульсов напряжения, вход которого соединен с выходом импульса обратного хода развертки частоты свип—генератора, а выход - с вторым входом перемножителя сигналов и вторым входом делителя сигналов.For this, in an FM reflectometer containing a sweep generator and a mixer incident and reflected from the microwave wave path in series, as well as a weight processing signal generating unit, a tunable filter and an indicator, an input signal multiplier is connected in series to the mixer output, a tunable filter and an input a signal divider, the input and output of which through the input and the first switch are connected to the input of the indicator, to another. The input of the indicator is connected to the second input a second switch mechanically coupled to the first switch and connected respectively to the second output of the tunable filter and the second output of the sweep generator; the weight processing signal generating unit is made in the form of a voltage pulse shaper, the input of which is connected to the output of the reverse sweep pulse of the sweep generator frequency, and the output is connected to the second input of the signal multiplier and the second input of the signal splitter.

На чертеже приведена структурная схема ЧМ-рефлектометра.The drawing shows a structural diagram of an FM reflectometer.

ЧМ-рефлектометр содержит последовательно соединенные свип-генератор 1 и смеситель 2 падающей и отраженной от исследуемого сверхвысокочастотного тракта 3 волн, а также блок 4 фор- $ мирования сигнала весовой обработки, перестраиваемый фильтр 5 й индикатор 6. При этом к выходу смесителя 2 последовательно подключены перемножитель 7 сигналов, перестраиваемый фильтр 5 10 и делитель 8 сигналов, вход и выход которого через переключатель 9 соединены с входом индикатора 6, к другому входу которого подключен переключатель 10, механически связанный с перекпю- 15 чателем 9 и подключенный соответственно к второму выходу перестраиваемого фильтра 5 и второму выходу свип-гене.ратора 1, Блок 4 формирования ..сигнала весовой обработки выполнен в виде 20 формирователя импульсов напряжения, вход которого соединен с выходом импульса обратного хода -развертки частоты свип-генератора 1, а выход - с вторым входом перемножителя 7 сигналов 25 и вторым входом делителя 8 сигналов.The FM reflectometer contains a sweep generator 1 connected in series and a mixer 2 of the 3 waves incident and reflected from the studied microwave path, as well as a weight processing signal generating unit 4, a tunable filter 5th indicator 6. In this case, the mixer 2 is connected in series to the output a signal multiplier 7, a tunable filter 5 10 and a signal divider 8, the input and output of which through a switch 9 are connected to the input of the indicator 6, to the other input of which a switch 10 is connected, mechanically connected to the switch by the switch 15 and connected respectively to the second output of the tunable filter 5 and the second output of the sweep generator 1, Generator 4. The weighting signal is made in the form of 20 voltage pulse shapers, the input of which is connected to the output of the reverse-pulse the frequency of the sweep generator 1, and the output with the second input of the multiplier 7 signals 25 and the second input of the divider 8 signals.

ЧМ-рефлектометр работает следующим образом.An FM reflectometer works as follows.

Сигнал биений падающей и отраженной волн ЧМ СВЧ сигнала, в значениях 30 частоты составляющих которого заложена информация о местоположениях нерегулярностей по длине исследуемого сверхвысокочастотного тракта 3, а в амплитудах - информация о коэффициенте 35 отражения нерегулярностей, с выхода смесителя 2 подается на вход перестраиваемого фильтра 5 через перемножитель 7 сигналов, представляющий собой усилитель с регулируемым напряжением ⁴⁰коэффициентом передачи. Спектры сигналов биений от отдельных нерегулярностей занимают минимальную полосу частот при произвольном скачке фазы на границах периодов развертки частоты ⁴⁵свип-генератора 1, в случае, если обгибающая этих сигналов имеет колоколообразную форму, выражаемую функцией Хеминга:The beat signal of the incident and reflected waves of the FM frequency microwave signal, in the values of 30 frequency components of which information about the locations of irregularities along the length of the investigated microwave path 3 is included, and in the amplitudes - information about the reflection coefficient 35 of irregularities, from the output of the mixer 2 is fed to the input of the tunable filter 5 through a signal multiplier 7, which is an amplifier with an adjustable voltage ⁴⁰ transmission coefficient. Spectra of beat signals from individual irregularities occupy minimum bandwidth with arbitrary phase discontinuity at the boundaries of scanning periods ⁴⁵ sweep frequency generator 1, if obgibayuschaya these signals has a bell-shaped function expressed Hemet:

ίΕΆ Ύ — > < 5θ Ц)Ю-0рв +0,92-COS^Z У’ - Τ’ где Т-период развертки частоты свипгенератора 1.ίΕΆ Ύ -><5θ C) S-0rv + 0.92-COS ^Z Y '- Τ' where is the T-period of the sweep frequency sweep generator 1.

Управляющее напряжение, реализующее функцию Хеминга, вырабатывается блоком 4 формирования сигнала весовой обработки, принцип работы которого заключается в формировании суммы посто янного напряжения и косинусквадратного импульса, имеющего привязку по фазе - 90° к моменту окончания синхронизирующего импульса обратного хода развертки частоты свип-генератора 1. Длительность косинусквадратного импульса устанавливается частотой генератора гармонического напряжения, входящего в состав блока 4 формирования сигнала весовой обработки, и равна длительности развертки частоты свип-генератора. Привязка по фазе осуществляется автоматическим фазовращателем, входящим в состав блока 4 формирования весовой обработки, устанавливающим в момент прихода синхронизирующих импульсов свип-генератора такой сдвиг фазы, что выходной сигнал к моменту окончания синхронизирующего импульса имеет сдвиг фазы-ЧО®..The control voltage that implements the Heming function is generated by the weight processing signal generating unit 4, the principle of operation of which is to form the sum of the constant voltage and cosine-squared pulse, which is phase locked - 90 ° to the end of the synchronization pulse of the reverse sweep of the frequency sweep generator 1. The duration of the cosine-squared pulse is set by the frequency of the harmonic voltage generator, which is part of the weight processing signal generating unit 4, and is equal to and the duration of the sweep frequency sweep generator. Phasing is carried out by an automatic phase shifter, which is part of the weight processing forming unit 4, which sets at the moment of arrival of the synchronizing pulses of the sweep generator such a phase shift that the output signal at the end of the synchronizing pulse has a phase shift-ChO® ..

Перестраиваемый фильтр 5 выделяет полосу частотj соответствующую выбранной нерегулярности, и, поскольку сигналы биений на входе подвергались весовой обработке, взаимное влияние неоднородностей вследствие перекрытия спектров сведено к минимуму, обусловленному разрешающей способностью метода измерения и частотными характеристиками нерегулярностей. Выходной сигнал перестраиваемого фильтра 5, поданный на вертикальный канал индикатора 6, вместе с управляющим перестройкой перестраиваемого фильтра 5 напряжением, поданным на горизонтальный канал индикатора 6 характеризует панорамное распределение нерегулярностей по длине исследуемого сверхвысокочастотного тракта 3 со средним по частотному диапазону значением коэффициента отражения нерегулярностей. При измерении частотных характеристик нерегулярностей выходной сигнал перестраиваемого фильтра 5, предварительно настроенного на выбранную нерегулярность^ через делитель 8 сигналов, устраняющий весовую обработку сигнала биений, подается на вертикальный канал индикатора 6. На горизонтальный канал индикатора 6 подается напряжение с модулятора свип-генератора 1, что позволяет наблюдать на экране индикатора 6 частотную характеристику нерегулярности.The tunable filter 5 selects the frequency band j corresponding to the selected irregularity, and since the beat signals at the input were subjected to weight processing, the mutual influence of inhomogeneities due to overlapping spectra is minimized due to the resolution of the measurement method and the frequency characteristics of irregularities. The output signal of the tunable filter 5, applied to the vertical channel of the indicator 6, together with the control tuning of the tunable filter 5, by the voltage applied to the horizontal channel of the indicator 6, characterizes the panoramic distribution of irregularities along the length of the investigated microwave frequency path 3 with the average frequency reflection coefficient of irregularities. When measuring the frequency characteristics of irregularities, the output signal of the tunable filter 5, pre-tuned to the selected irregularity ^ through the signal divider 8, which eliminates the weighting of the beat signal, is fed to the vertical channel of indicator 6. The horizontal channel of indicator 6 is supplied with voltage from the sweep generator modulator 1, which allows observing on the screen of indicator 6 the frequency response of irregularity.

ЧМ-рефлектометр пр сравнению с про— тотипом имеет более высокую точность и разрушающую способность по длине измерения структуры исследуемого сверх- выЬокочастотного тракта и его отдельΗώχ'элементов.Compared to the prototype, the FM reflectometer has higher accuracy and destructive ability along the length of the measurement of the structure of the studied microwave frequency path and its individual elements.

Claims

This invention relates to a radio measuring technique. The FM reflectometer is known, which contains a sweep generator and a mixer that are connected in series and reflected from the microwave frequency path under study, as well as a signal shaping unit for the weight processing tunable filter and indicator l. However, the well-known FM reflectometer has a low accuracy and destructive ability along the length of the structure measurement of the microwave frequency path under study. and its individual elements. The purpose of the invention is to increase the accuracy and resolution along the length of the measurement of the structure of the investigated microwave path and its individual elements. To do this, in the FM reflectometer containing successively connected sweep generator and mixer incident and reflected from the microwave frequency path under study, as well as a weight processing signal shaping unit, tunable filter and indicator, the input signal multiplier is sequentially connected to the mixer output, a tunable filter and an input signal divider are connected in series the input and output of which through the input and the first switch are connected to the input of the indicator, the second input is connected to another input of the indicator enny switch mechanically coupled with the first switch and connected respectively to the second output of the tunable filter and the second output of the sweep generator; The signal processing unit of the weight processing is made in the form of a voltage pulse generator, the input of which is connected to the output of the reverse sweep pulse of the sweep frequency generator, and the output to the second input of the signal multiplier and the second input of the signal divider. The drawing shows a structural diagram of the FM reflectometer. The 3 FM reflectometer contains a series-connected sweep generator 1 and a mixer 2 that incident and reflected 3 waves from the microwave path under study, as well as a weight processing signal generating unit 4, a tunable filter 5 and an indicator 6 In this case, the multiplier is sequentially connected to the output of the mixer 2 7 signals, Tuning filter 5 and divider 8 signals, the input and output of which through switch 9 are connected to the input of indicator 6, to another input of which is connected switch 10, mechanically connected to the switch 9 and connected appropriately to the second output of the tunable filter 5 and the second output of the sweeper generator 1, Shaping unit 4: the weight processing signal is in the form of a voltage pulse shaper, the input of which is connected to the output of the reverse flyback frequency Sweep-geerator I, and the output is with a BTop "iiM input of the multiplier 7 signal and the second input of the divider 8 signals. The FM refractometer operates as follows. The beat signal of the incident and reflected waves of the FM microwave signal, in the values of the frequency of the components of which information is placed on the locations of irregularities along the length of the microwave tract 3 under study, and in amplitudes - information on the reflection of the irregularities, is output from mixer 2. tunable filter 5 through the signal multiplier 7, which is an amplifier with an adjustable voltage transfer ratio. The spectra of the beat signals from individual irregulars occupy the minimum frequency band with an arbitrary phase jump at the boundaries of sweep generator frequency sweep 1, in the event that the bending of these signals has a bell shaped form, expressed by the Heming function: U) (i), 91COS - T where T is the sweep frequency sweep T-period 1. The control voltage realizing the Heming function is generated by the weight processing signal processing unit 4, the principle of operation of which is the formation of the sum of the post voltage 7 squared pulse phase locked to 90 by the time the sweep generator sweeps back to reverse the sweep generator 1. The duration of the square squared pulse is determined by the frequency of the harmonic voltage generator included in the weight processing signal processing unit 4, and is equal to the frequency sweep duration sweep generator. Phasing is carried out by an automatic phase shifter, which is part of the weight processing unit 4, which sets the phase shift at the time of arrival of the sweep generator clock so that the output signal has a phase shift of 90 by the end of the clock pulse. 5 assigns a frequency band corresponding to the selected irregularity, and, since the beating signals at the input were subjected to weight processing, the mutual influence of inhomogeneities due to overlapping spectra but to a minimum caused by resolution -method and measuring the frequency characteristics of irregularities. The output signal of the tunable filter 5 supplied to the vertical channel of the indicator 6, together with the control tuning of the tunable filter 5 voltage applied to the horizontal channel of the indicator 6, characterizes the panoramic distribution of irregularities along the length of the microwave path 3 under investigation with the average over the frequency range the reflection coefficient of irregular rnnost. When measuring the frequency characteristics of the irregularities, the output signal of the tunable filter 5, preset to the selected irregularity, through the divider 8 signals, eliminating weight processing of the beat signal, is fed to the vertical channel of the indicator 6. The horizontal channel of the indicator 6 is supplied with voltage from the modulator of the sweep -generator I, which makes it possible to observe the frequency response of an irregularity on the screen of the indicator 6. The FM reflectometer, compared with the prototype, has a higher accuracy and destructive ability along the length of the measurement of the structure of the studied superhigh-frequency path and its individual elements. The invention of the FM reflectometer containing a sequentially connected sweep generator and a mixer incident and reflected from the studied UHF wave tract, as well as a signal processing unit for weight processing, a tunable filter and an indicator that differs in that resolution along the length of the measurement of the structure of the studied microwave path and its individual elements, the input signal multiplier is sequentially connected to the output of the mixer, rearranging The input filter and the input divider of the signals, the input and output of which are connected through the input 76 first switch to the indicator input, to the other input of the indicator is connected the second on-switch, mechanically connected to the first switch and connected to the second output of the tunable filter and the second output of the sweep generator, block the formation of the weight processing signal is made in the form of a voltage pulse former, the input of which is connected to the output of the reverse pulse of the sweep frequency sweep, move - with the second input of the signal multiplier and the second input of the signal divider. Sources of information taken into account in the examination of J. The Locating ReflecCbmeter. IEEE Transactions on MTT, 1972, MTT-20, ff 20, p. 105-117 (prototype)