RU2649079C1 - Multi-channel fiber optic system for synchronous starting of recorders - Google Patents

Abstract

FIELD: instrument engineering.

SUBSTANCE: invention relates to the field of recording pulse signals and relates to a multi-channel fiber optic system for synchronous triggering of recorders. System includes a transmitting unit with one electric starter input and several optical outputs, receiver units and recorders. Outputs of the transmitting unit are connected by optical fibers of the same length to each receiver unit, and each receiving unit is connected to a corresponding recorder. Each receiving unit includes a photoelectric receiver. Transmitting unit includes a series-connected electrical pulse former, an optical transmitter and an optical coupler, forming optical signals. Optical transmitter is made on the basis of a super-luminescent diode or a semiconductor laser. Electric pulse generator is made on the basis of a trigger scheme with subnanosecond speed of response, and photoelectric receivers also have subnanosecond speed of response.

EFFECT: technical result is the ensuring of the synchronization of the triggering of recorders with subnanosecond accuracy.

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Description

The invention relates to the field of registration of pulse signals, namely to multi-channel systems for recording electrical parameters of electrophysical installations, for example, electron accelerators.

To control the operation of an electrophysical installation, synchronized registration of electrical signals from spatially separated sensors subject to electromagnetic interference is required. Therefore, it is necessary to provide noise-free synchronous start-up of recorders (oscilloscopes). To ensure noise immunity, fiber optic communication is used.

A multi-channel fiber-optic device for synchronously triggering oscilloscopes is known (see CN patent No. 102072979 dated 10.26.2010, Multi-point synchronous triggering system and method in VFTO (Very Fast Transient Overvoltage) measurement, published May 25, 2011), comprising a transmitting unit, including one transistor-based electrical pulse generator connected to several LED-based optical transmitters connected in parallel, photoelectric receivers and recorders, each photoelectric receiver connected to an optical transmitting unit im fiber. The branching is performed at the output of the common for all LEDs of the electric pulse shaper.

The disadvantage of this multi-channel fiber-optic device for synchronous triggering of oscilloscopes is the use of LEDs in the optical transmitters. having limited speed (more than 1.5 ns), depending on the LED instance and its temperature.

Known multi-channel fiber optic system for synchronous triggering of recorders (patent for invention No. 2456547 dated 03/18/2011. Multi-channel fiber optic system for synchronous triggering of registrars, published on July 20, 2012). comprising at least one channel including a transmitting unit, a receiving unit and a recorder, each receiving unit being connected to the transmitting unit by an optical fiber of the same length. The claimed system contains several shapers of electric pulses and several optical transmitters (according to the number of channels). Each transmitting unit performs the function of converting from electrical to optical signal. The demultiplexing function occurs at the inputs of the transmitting units. Each electric pulse shaper is connected to a corresponding optical transmitter, and each receiving unit includes a photoelectric receiver. Optical transmitters are based on LEDs.

The disadvantages of this multichannel fiber-optic system for synchronous triggering of recorders are the limited performance of LED-based optical transmitters, as well as the fact that demultiplexed signals in the system pass an additional path in each channel through the transmitters of the transmitting units, undergoing temporary distortions.

The problem solved by the claimed invention is the creation of a noise-resistant multi-channel fiber-optic system for synchronous start of registrars with a minimum variation in the timing of the triggering of the start of the registrars.

Achievable technical result of the claimed invention is to ensure synchronization of the start of registrars with subnanosecond accuracy due to the shortening of the leading edge of the trigger pulse and high stability of the delay in the optical fiber. In addition, the claimed invention enables the economical use of technical means in the transmitting unit.

To achieve a technical result in a multi-channel fiber-optic system for synchronously starting recorders, comprising a transmitting unit with an electric pulse generator and an optical transmitter, receiving units and recorders, where each receiving unit is connected to the transmitting unit by an optical fiber of the same length, while the transmitting unit performs the function conversion from electrical to optical signal, and each receiving unit connected to the corresponding registrar includes a photoelectric An optical receiver is new in that the transmitting unit includes an optical splitter for multiplexing the signal, while the electric pulse shaper, the optical transmitter, and the optical splitter are connected in series, the optical transmitter being made on the basis of a superluminescent diode or a semiconductor laser (devices using stimulated emission), the electric pulse shaper is made on the basis of a trigger circuit with subnanosecond speed, and The photoelectric receiver also has subnanosecond speed.

The use of fiber-optic communication lines galvanically isolates the recorders from each other. The use of a single shaper with an optical transmitter based on subnanosecond (less than 1 ns) superluminescent diode or a semiconductor laser instead of several shapers with LED emitters with a unit speed does not allow to save technical means and reduce the time spread of the moment the recorders start up. The use of an electric pulse shaper made on the basis of a trigger circuit, for example, on an avalanche transistor, makes it possible to form a subnanosecond front of the emitter pump current pulse (superluminescent diode or semiconductor laser). To ensure the conversion of an optical signal into an electric signal with subnanosecond speed in each receiving unit, the photoelectric receiver is based on high-speed PIN photodiodes.

This set of essential features allows you to run multiple registrars with a spread of less than 1 ns.

In FIG. 1 is a structural diagram of a multi-channel fiber-optic system for synchronously starting recorders, where:

1 - transmitting unit;

2 - receiving unit;

3 - registrar;

4 - optical fiber;

5 - trigger circuit;

6 - optical splitter;

7 photoelectric receiver;

8 - PIN photodiode.

In FIG. 2 shows a variant of the trigger circuit of a transmitting unit of one of the channels of a multichannel fiber-optic system for synchronously starting recorders, where:

9 - separation-differentiating capacitor;

10 - bit resistor;

11 - avalanche transistor;

12 - storage capacitor;

13 - charging resistor;

14 - an optical transmitter based on a superluminescent diode or a semiconductor laser;

15 - optical cable.

A multi-channel fiber-optic system for synchronously starting recorders comprises a transmitting unit 1, receiving units 2 and recorders 3. Each receiving unit 1 is connected to the transmitting unit 2 by an optical fiber 4 of the same length. The transmitting unit 1 performs the function of converting from electrical to optical signal. Each receiving unit 2. connected to a respective recorder 3, includes a photoelectric receiver 7 based on a PIN photodiode 8. The transmitting unit includes one electric pulse generator based on the trigger circuit 5, an optical transmitter 14, and an optical splitter 6 connected to each other sequentially using an optical cable 15. The optical transmitter 14 is made on the basis of a superluminescent diode.

A multi-channel fiber optic system for synchronously starting recorders works as follows (see Fig. 1). An input pulse is applied to the input of the transmitting unit 1 (see Fig. 1), which triggers the trigger circuit 5. The trigger circuit 5 generates a current pulse with a subnanosecond front, which goes to the optical transmitter 14. The light signal from the optical transmitter through the optical cable 15 enters the input of the optical splitter 6, where demultiplexed. A group of optical signals from the output of the splitter is fed through personalized optical fibers 4 to the receiving units 2, where it is converted into electrical signals, each arriving at its own recorder 3.

In order to confirm the feasibility of the claimed object and to achieve a technical result, a two-channel mock-up of a fiber-optic system for synchronous triggering of recorders (LeCroy WM-8500A oscilloscope with a band of 5 GHz) was made and tested in laboratory conditions, made according to the diagrams shown in the drawings.

The layout was assembled using two photoelectric detectors 7 based on PIN photodiodes 8 of type ФД271-Д with a 50 V back-mixing circuit. The optical transmitter 14 was made on the basis of a superluminescent diode of the type ИЛПН-301-1. An optical splitter CE-2-1x2-1.31-50 / 50-SC / SC was used; SC of LLC Opted. The system was assembled using 62.5 μm ST / ST patch cords and SC / ST transitions. Trigger circuit - shaper of current pulses (from 0.7 to 1 A) of subnanosecond duration was performed on BSY34 type 11 avalanche transistors and was used to pump a superluminescent diode. The trigger pulse was supplied through a separation-differentiating capacitor 9 to the base of the avalanche transistor 11, causing an avalanche breakdown. The charge accumulated on capacitor 12 was switched to a superluminescent diode, generating a pulsed current with a subnanosecond front in the latter. After the passage of the pulse, the resistors 10 and 13 returned the circuit (charge on the capacitors) to its original state. The power of each receiving unit 2 was carried out from the USB port of the corresponding recorder 3.

The tests showed the feasibility of the claimed device, and was achieved synchronization start-up of 0.3 ns.

Claims (1)

A multichannel fiber-optic system for synchronously starting recorders, comprising a transmitting unit with one electrical starting input and several optical outputs, receiving units and recorders, where the outputs of the transmitting unit are connected by optical fibers of the same length to each receiving unit, and each receiving unit is connected to a corresponding registrar wherein each receiving unit includes a photoelectric receiver, and in the transmitting unit is carried out as a conversion from into an optical signal, and signal branching, characterized in that the transmitting unit includes one electric pulse shaper, an optical transmitter and an optical splitter forming optical output signals, interconnected in series, the optical transmitter being made on the basis of a superluminescent diode or a semiconductor laser, the electric pulse shaper is based on a trigger circuit with subnanosecond speed, and the photoelectric receiver also has subnanosecond speed.

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