CN103123739B - Optical fiber perimeter intrusion alarm system signal processing unit proving installation - Google Patents

Abstract

The invention discloses a kind of optical fiber perimeter intrusion alarm system signal processing unit proving installation, it is characterized in that: comprise sensing optic cable, entanglement, impact ball, 3 × 3 coupling mechanisms, incident light source, delay of feedback loop, there is 1 × n optical splitter of even splitting ratio, described sensing optic cable is fixed on entanglement, its one end is reflection end, the other end is connected with one end of 3 × 3 coupling mechanisms, the other end of 3 × 3 coupling mechanisms is connected with incident light source and 1 × n optical splitter, 3 × 3 coupling mechanisms are also circumscribed with the delay of feedback loop connecting its two ends, the n road of 1 × n optical splitter exports n the expanding channels with measured signal processing unit, described impact ball is arranged on the top of entanglement, and the mode of freely falling body can drop into entanglement produces and impact.The present invention can provide reproducible, that impact energy is controlled impact, and the sense light signal impacting generation, through 1 × n optical splitter, has higher conforming standard input signal for multiple channel test provides.

Description

Optical Fiber Perimeter Intrusion Alarm System Signal Processing Unit Test Device

technical field

The invention relates to an optical fiber vibration sensing shock response performance test device, in particular to a multi-channel shock response sensitivity calibration and inspection device with high repeatability and channel consistency.

Background technique

The fiber optic perimeter intrusion alarm system is a security alarm system constructed based on the principle of vibration sensing, using technologies such as laser, optical fiber sensing, and optical communication. It is a modern defense system that monitors and alerts emergencies that threaten security. The optical fiber perimeter intrusion alarm system can realize multi-channel (such as 8 or 16 channels) synchronous real-time monitoring. In practical applications, due to the device performance and production process, the consistency of each channel of the signal processing unit will be different, and it needs to be tested and calibrated. Consistency of each channel, and provide data support for the shock response of the system.

At present, there is no special test device on the market. The usual sensitivity detection method is to test the sensitivity by simulating various actions of people after installation on site. Such a detection method is highly random and not repeatable. At the same time, it cannot provide Channel coherent multichannel shock response sensing of optical signals. Therefore, a test device with test repeatability and channel consistency is needed to test the impulse response sensitivity of the signal processing unit, so as to calibrate the consistency of each channel and provide data support for the impulse response of the system.

Contents of the invention

The purpose of the present invention is to provide a signal processing unit testing device for an optical fiber perimeter intrusion alarm system to provide a multi-channel impulse response sensing light signal with repeatability and channel consistency for the test of the impulse response sensitivity of the signal processing unit, thereby calibrating the signal processing The consistency of each channel of the unit, and provide data support for the shock response of the system.

For reaching this purpose, the present invention adopts following technical scheme:

A test device for a signal processing unit of an optical fiber perimeter intrusion alarm system, including a sensing optical cable, barbed wire, an impact ball, a 3×3 coupler, an incident light source, a feedback delay loop, and a 1*n splitter with a uniform splitting ratio. The sensing optical cable is fixed on the barbed wire, one end is the reflective end, the other end is connected to one end of the 3×3 coupler, the other end of the 3×3 coupler is connected to the incident light source and the 1*n beam splitter, and the 3×3 coupling There is also a feedback delay loop connected to both ends of the device, and the n-way output of the 1*n optical splitter is connected to the n channels of the signal processing unit to be tested. The impact ball is set above the barbed wire and can fall freely. Way to drop onto the barbed wire for impact.

Preferably, the impact ball is made of ferromagnetic material, the impact ball is attracted to an electromagnet, and the electromagnet is fixed on the bracket.

Preferably, the feedback delay loop is an optical fiber delay line.

Preferably, the reflective end of the sensing optical cable adopts a Faraday rotating mirror.

Preferably, the reflectivity of the reflective end of the sensing optical cable is greater than 75%.

Preferably, the 3×3 couplers are arranged in a fret shape.

Preferably, the incident light source is a superluminescent diode (SLD) light source.

Preferably, the impact ball has a diameter of 10mm-20mm.

Preferably, the impact ball is a solid ball.

Preferably, the control switch of the electromagnet is a self-resetting normally closed switch,

The beneficial effects of the present invention are as follows: the impact energy is generated by the free fall of the impact ball, which can provide impact with good repeatability and controllable impact energy, and the sensing light signal generated by the impact can generate n channels of optical power through a 1*n beam splitter Equal sensing light signals provide a standard input signal with high consistency for multi-channel testing.

Description of drawings

Fig. 1 is a working principle diagram of the present invention;

Fig. 2 is a connection schematic diagram of an embodiment of the present invention;

Fig. 3 is a two-channel impulse signal voltage-time trend diagram of a certain group of test records in an embodiment of the present invention;

In the figure: 1. Fixing screw; 2. Movable load-bearing rod; 3. Electromagnet; 4. Steel ball; 5. Support frame; 6. Electromagnet control switch; 7. Faraday rotating mirror; Sensing optical cable; 10. Test host; 11. Signal processing unit to be tested; 12. Analysis software.

detailed description

The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

The present invention adopts interferometric optical fiber sensing technology, utilizes the optical cable to sense the detected physical field, such as temperature, pressure or vibration, etc., and thus causes a phase delay of the light guide, that is, a change in the phase, thereby causing a change in the output light intensity, and then Know the change of the physical field to be measured.

As shown in Figure 1, the incident light source is a superluminescent light-emitting diode (SLD) light source, the 3×3 couplers are arranged in a square shape, the feedback delay loop is a section of fiber delay line with a delay of τ, and D is the disturbance source (ie The position of the disturbance signal can be any position on the optical cable), the reflection end is a mirror reflection end (a Faraday rotating mirror can be used or a reflection film can be coated on the fiber end, and the reflectivity is greater than 75%), 1*n (n=8 or 16) The optical splitter divides the sensing light signal into n channels, the signal processing unit to be tested is composed of photoelectric conversion and amplification circuits, and the analysis software displays and analyzes the sensing status in real time.

Only the light that forms interference can carry the phase information of the disturbance point D. According to the characteristics of the splitting ratio of the 3×3 coupler is 1:1:1, determine the optical path as shown in Table 1.

It can be seen from Figure 1 and Table 1 that the incident light is reflected and received by the 1*n beam splitter, the strongest optical path is b-e-f-e-c, and there is no other optical path close to its optical path, so the function of this optical path is only to increase the straight path Part of the light intensity will not affect the final result; while the two paths of b-d-a-e-f-e-c and b-e-f-e-a-d-c pass through the coupler three times, so the light amplitude is the same and the optical path is similar. The former is delayed in the disturbance time compared to the latter τ, the two can form interference, and its coherent light carries the disturbance information of the disturbance point D; as for the light of other optical paths, it needs to pass through the coupler more than 4 times, although there are pairs of light that can interfere with each other, but Its strength is so weak that it can be ignored.

Table 1

As shown in Figure 2, the movable load-bearing rod 2 is fixed on the support frame 5 through the fixing screw 1, and the position 2 of the movable load-bearing rod can be adjusted by loosening the fixing screw 1, so that the whereabouts of the steel ball 4 can reach the best position. The steel ball 4 is sucked on the electromagnet 3, and the electromagnet 3 is fixed on the movable load-bearing rod 2, and its control wire is connected to the control switch 6 from the movable load-bearing rod 2 shell. Press the control switch 6, the electromagnet 3 loses its magnetic force when the power is turned off, the steel ball 4 falls freely, and hits the wire welded net bound with the sensing optical cable 9, the signal processing unit 11 to be tested collects the optical signal from the test host 10 in real time and converts it into For the electrical signal, the analysis software 12 records the maximum value of the impact to complete a test.

The control switch 6 is a self-resetting normally closed switch. After being pressed, the electromagnet 3 loses its magnetic force when it is powered off, and the steel ball 4 falls freely. Then, the control switch 6 automatically resets, and the steel ball 4 is adsorbed on it, and the next set of tests can be started .

The steel ball is in a static state before falling, and the initial kinetic energy is zero, so the impact energy it produces is proportional to the mass of the steel ball and the falling height. The falling height of the steel ball is fixed, and a group of steel balls of different masses are selected to produce different impact energies. The steel ball is a solid ball with a diameter ranging from 10mm to 20mm.

As shown in Figure 3, the signal processing unit 11 to be tested collects the optical signal in real time and converts it into a standard voltage signal, the analysis software collects and records the voltage value, the sampling frequency is 1 Hz, and each group of tests is repeated 5 times. Each impact will generate a maximum response voltage value, and the peak-to-peak value of the generated voltage will be used as a reference, which can avoid the influence of the circuit zero point on the test results, and the average value of 5 times will be taken as the system response value Vsignal of a group of tests. This repeated operation mode can effectively eliminate gross errors in the testing process.

The impact dynamic response and the static response when there is no signal input of the signal processing unit 11 to be tested are respectively recorded, and the signal-to-noise ratio is calculated to obtain its response sensitivity.

As shown in Table 2, the shock response test data of 8 channels, test error = (Vmax-Vmin)/Vsignal, the error of 5 tests for each channel is less than 10%, indicating that the shock test has good repeatability; The channel-to-channel variance of the test channels was less than 4%, indicating good channel consistency. Taking the test mean value, the difference between channels is 1.8%, which shows that the signal processing unit 11 under test has a good impulse response consistency.

Table 2

Turn off the light source input, so that the test host 10 has no optical signal output. At this time, the analysis software 12 records the channel static response of the signal processing unit 11 to be tested. The average result after testing 10 groups is shown in Table 3, according to the formula of signal-to-noise ratio db=10log10Vsignal/Vnoise Calculate the signal-to-noise ratio of each channel, the signal-to-noise ratio of each channel is distributed around 30db, and the relative difference of each channel is 2.2%, indicating that it has better signal-to-noise ratio characteristics. Although the relative difference of the static response among the channels is 14.7%, the absolute difference is small and does not affect the system response.

table 3

Static Response Vnoise Shock response Vsignal SNRdb channel 1 0.007 7.9 30.3 channel 2 0.008 8.0 30.1 channel 3 0.008 7.9 29.9 channel 4 0.008 8.0 30.2 channel 5 0.007 7.9 30.4 channel 6 0.007 7.9 30.3 channel 7 0.007 8.0 30.6 channel 8 0.008 7.9 30.1 Channel Difference % 14.7 1.8 2.2

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A signal processing unit test device for an optical fiber perimeter intrusion alarm system, characterized in that: it includes a sensor optical cable, barbed wire, impact ball, 3 × 3 coupler, incident light source, feedback delay loop, a 1 with uniform light splitting ratio *n optical splitter, the sensing optical cable is fixed on the barbed wire, one end of which is the reflective end, the other end is connected to one end of the 3×3 coupler, the other end of the 3×3 coupler is connected to the incident light source and 1*n optical splitter connection, the 3×3 coupler is also externally connected with a feedback delay loop connecting its two ends, the n-way output of the 1*n optical splitter is connected to the n-channels of the signal processing unit to be tested, and the impact ball is set above the barbed wire , and can fall onto the barbed wire in a free fall to generate impact. 2. The optical fiber perimeter intrusion alarm system signal processing unit test device according to claim 1, characterized in that: the impact ball is made of ferromagnetic material, the impact ball is attracted to the electromagnet, and the electromagnet fixed on the bracket. 3. The test device for the signal processing unit of the optical fiber perimeter intrusion alarm system according to claim 1, wherein the feedback delay loop is an optical fiber delay line. 4. The test device for the signal processing unit of the optical fiber perimeter intrusion alarm system according to claim 1, characterized in that: the reflection end of the sensing optical cable adopts a Faraday rotating mirror. 5. The test device for the signal processing unit of the optical fiber perimeter intrusion alarm system according to claim 1, characterized in that: the reflectivity of the reflective end of the sensing optical cable is greater than 75%. 6. The test device for the signal processing unit of the optical fiber perimeter intrusion alarm system according to claim 1, characterized in that: the 3×3 couplers are arranged in the shape of a square. 7. The test device for the signal processing unit of the optical fiber perimeter intrusion alarm system according to claim 1, wherein the incident light source is a superluminescent light emitting diode light source. 8 . The testing device for the signal processing unit of the optical fiber perimeter intrusion alarm system according to claim 1 , wherein the impact ball has a diameter of 10 mm to 20 mm. 9. The test device for the signal processing unit of the optical fiber perimeter intrusion alarm system according to claim 1, characterized in that: the impact ball is a solid ball. 10. The test device for the signal processing unit of the optical fiber perimeter intrusion alarm system according to claim 2, wherein the control switch of the electromagnet is a self-resetting normally closed switch.