SU590821A1

SU590821A1 - Device for measuring moving magnetic tape parameters

Info

Publication number: SU590821A1
Application number: SU762365247A
Authority: SU
Inventors: Павел Иннокентьевич Госьков; Юрий Константинович Шелковников; Алексей Григорьевич Якунин; Юрий Александрович Шевелев; Владимир Васильевич Медвецкий; Римвидас Пятро Ясинавичюс
Original assignee: Томский Институт Автоматизированных Систем Управления И Радиоэлектроники; Предприятие П/Я А-3593
Priority date: 1976-05-11
Filing date: 1976-05-11
Publication date: 1978-01-30

Description

1one

Изобретение относитс к области Приборостроени , а именно к устройствам измерени в аппаратуре магнитной записи. The invention relates to the field of Instrumentation, namely to measurement devices in magnetic recording equipment.

Известны устройства дл измерени параметров движущейс магнитной ленты, позвол ющие измер ть параметры ленты бесконтактным способом 1, 2.Devices are known for measuring the parameters of a moving magnetic tape, which make it possible to measure the parameters of the tape in a contactless manner 1, 2.

Наиболее близким по технической сущности к изобретению вл етс устройство, содержащее источники света, фотоприемники, магнитную ленту, расположенную между ними, усилители , линию задержки, аттенюаторы, сумматор и регистрирующий узел 3.The closest in technical essence to the invention is a device comprising light sources, photodetectors, a magnetic tape interposed between them, amplifiers, a delay line, attenuators, an adder and a recording node 3.

Дл такого устройства характерна недостаточно высока точность измерени параметров движущейс магнитной ленты.For such a device, the measurement accuracy of the parameters of the moving magnetic tape is not sufficiently high.

Цель изобретени - повышение точности измерени .The purpose of the invention is to improve the measurement accuracy.

Это достигаетс тем, что предлагаемое устройство снабжено источником -посто нного налр лсени , генератором пилообразного напр жени , дифференциальным трансформатором и блоком усилени и разделени видеосигналов , а регистрирующий узел выполнен из двух блоков - импульсного вольтметра и измерител временных интервалов. При этом параллельно соединенные эмиттеры фотоприемников , выполненных в виде сканисторов, подключены к источнику посто нного тока, подсоединенного к генератору пилообразногоThis is achieved by the fact that the proposed device is equipped with a source of a -stable voltage, a sawtooth generator, a differential transformer and a video amplification and separation unit, and the recording unit is made of two units — a pulsed voltmeter and a time meter. In this case, parallel-connected emitters of photodetectors, made in the form of scanstors, are connected to a DC source connected to a sawtooth generator

напр жени , выход которого соединен со средней точкой первнчной обмотки трансформатора , образующей две противофазно включенные полуобмотки, соединенные с соответствующими коллекторами сканисторов, и с одним из входов блока усилени и разделени видеосигналов, другой вход которого подключен к вторичной обмотке того же трансформатора , а выходы подсоединены один кvoltage, the output of which is connected to the midpoint of the transformer primary winding, forming two anti-phase semi-windings connected to the respective collectors of the scanstors, and one of the inputs of the video amplification and separation unit, the other input of which is connected to the secondary winding of the same transformer, and the outputs are connected one to

нмпульсному вольтметру, другой - к измерителю временных интервалов, причем на магнитную ленту нанесены оптически прозрачные метки. На чертеже показана блок-схема устройства дл измерени параметров движущейс магнитной ленты.An impulse voltmeter, another - to a time interval meter, with optically transparent marks affixed to the magnetic tape. The drawing shows a block diagram of a device for measuring parameters of a moving magnetic tape.

Магнитна лента 1 с нанесенной на ней оптически прозрачной меткой 2 расположена между источниками 4 света и сканисторамиMagnetic tape 1 with optically transparent label 2 placed on it is located between sources 4 of light and scanstors

5, 6. Между сканисторами находитс магнитна головка 7, относительно которой измер ютс угловые неремещени магнитной ленты 1. Источник 8 посто нного напр жени смещени подключен к параллельно соединенным5, 6. Between the scanstors there is a magnetic head 7, relative to which the angular displacements of the magnetic tape 1 are measured. A source 8 of a constant bias voltage is connected to parallel-connected

Claims

emitters of scanstors 5, 6, and a sawtooth voltage generator 9 - to the grounded output of the source 8 of the bias voltage and through the out-of-phase primary windings of the differentiating transformer 10 - to the collectors of the scanners 5, 6. The secondary winding of the differentiating transformer 10 is connected to the input of the electronic unit And gain and dividing the video signals whose outputs are connected to a pulse voltmeter 12 and a meter of 13 time slots. The device works as follows. The flow of light from sources 3, 4 is projected onto scanstors 5, 6 so that magnetic tape 1, moving between scanstors 5, 6 and light sources 3, 4, completely blocks the upper part of the light flux projected on scanners, leaving the bottom of the scanstors 5, 6 light zone 3-5 mm wide. This zone defines the working range of the measured angular displacement devices. The constant bias voltage from source 8. is applied to parallel-connected emitters of scanstors 5, 6, and the demand voltage from saw-tooth voltage generator 9 to the collectors of scanstors 5, 6 through the antiphase primary windings of the differentiating transformer 10. In the initial state at stationary: magnetic tape 1, it is achieved that on the secondary winding of the differentiating transformer 10 a total signal equal to the difference of video signals from both light fluxes is equal to zero. When the magnetic recording medium 1 is moving and its transverse movements are video signals are shifted in time relative to each other, and a differential signal is formed on the output winding of the transformer 10, the amplitude of which is proportional to the magnitude of this shift. This signal is extracted by the AND amplification and separation of video signals and recorded by a digital pulse voltmeter 12. To determine the speed of movement of a magnetic recording medium, optically transparent marks are applied to it by a laser or other method, which, when crossed by the scanner, form a current jump from a dark value in its photodiode cells to a value determined by the intensity of the radiation sources 3, 4 and the transparency of the optical mark 2. Current pulses arising from the Intersection of scanstors 5, 6 of the optical met In this case, video signals 11 are separated in the amplification and separation electronic unit 11, and 13 timeslots are fed to the meter. Thus, the speed of the tape is determined by measuring the time interval over which the mark 12 applied on the tape passes the distance between scanners 3, 4. The proposed device allows to increase the accuracy of measuring the parameters of the moving magnetic tape. The invention The device for measuring the parameters of a moving magnetic tape, containing two light sources, two photodetectors, a magnetic tape between them and a recording unit, characterized in that, in order to improve the measurement accuracy, it is equipped with a constant voltage source, a sawtooth generator , a differential transformer and a block for amplifying and separating video signals, and the registering node is made of two blocks — a pulsed voltmeter and a time interval meter, with A volume of parallel-connected emitters of photodetectors, made in the form of scanstors, is connected to a DC source connected to a sawtooth generator, the output of which is connected to the midpoint of the primary winding of the transformer, forming two anti-phase semi-windings connected to the corresponding scanner collectors and one of the inputs of the video amplification and separation unit, the other input of which is connected to the secondary winding of the same transformer, and the outputs are connected to one to a pulse voltmeter, the other to a time interval meter, with optically transparent marks attached to a magnetic tape. Sources of information taken into account in the examination 1. USSR author's certificate №255676, l. G 01 P 3/22, 1968.

2. USSR author's certificate number 455256, l. G OIL 5/10, 1972.

3. USSR author's certificate No. 292190, l. G 11B 27/26, 1969.