A shielding attenuation measurement method and device for aircraft wiring harness anti-wave sleeve

Abstract

The present application provides a method for measuring the shielding attenuation of an aircraft wiring harness anti-wave sleeve, the method comprising: applying input signals to a first measured wiring harness and a second measured wiring harness respectively, the first measured wiring harness is a measured wiring harness without an anti-wave sleeve, the second measured wiring harness is a measured wiring harness with an anti-wave sleeve, the frequency of the input signal is a preset frequency, and the power is a preset power level; measuring the current level I0(f) flowing through the first measured wiring harness and the current level I1(f) flowing through the second measured wiring harness; using the formula S(f)=20log(I0(f) / I1(f)), calculating the shielding attenuation S(f) of the aircraft wiring harness anti-wave sleeve.

Description

Technical Field

[0001] The invention relates to the field of shielding attenuation measurement of a wiring harness anti-wave sleeve, and in particular to a shielding attenuation measurement method and device for an aircraft wiring harness anti-wave sleeve. Background Art

[0002] Nowadays, a large number of aircraft wiring harnesses are equipped with anti-wave sleeves in order to effectively suppress the electromagnetic interference caused by the space electromagnetic environment (such as high-intensity radiation fields, lightning, static electricity, etc.) to the aircraft's electronic and electrical systems through cable field line coupling. Although anti-wave sleeves have a certain electromagnetic shielding protection effect on aircraft wiring harnesses, they will increase the weight and cost of the aircraft. On the premise of meeting the electromagnetic shielding protection requirements of aircraft wiring harnesses, aircraft designers tend to design or select light-weight and low-cost anti-wave sleeves. For this reason, it is necessary to measure the shielding attenuation of aircraft wiring harness anti-wave sleeves to obtain their shielding attenuation characteristics and avoid over-design and under-design of aircraft wiring harness electromagnetic shielding protection.

[0003] The shielding attenuation measurement of the wiring harness anti-wave sleeve generally refers to the foreign IEC 62153-4-3 and IEC 62153-4-4 standards, and uses the three-coaxial method to put the anti-wave sleeve into a special coupling measurement tube to measure the transfer impedance in the low frequency band and the shielding attenuation in the high frequency band. The coupling measurement tube is a limiting condition for whether the shielding attenuation characteristic measurement of the anti-wave sleeve can be carried out. Without the coupling measurement tube, aircraft designers cannot use the three-coaxial method to measure the shielding attenuation characteristics of the anti-wave sleeve. Summary of the invention

[0004] The purpose of the present invention is to propose a simple, easy-to-operate, accurate and efficient aircraft harness anti-wave sleeve shielding attenuation measurement method and device when there is no coupling measurement tube and the three-coaxial method measurement cannot be carried out, and the measurement frequency range is 10kHz to 400MHz.

[0005] In a first aspect, the present application provides a method for measuring shielding attenuation of an aircraft wiring harness anti-wave sleeve, the method comprising:

[0006] Applying input signals to a first measured wiring harness and a second measured wiring harness respectively, wherein the first measured wiring harness is a measured wiring harness without an anti-wave sleeve, and the second measured wiring harness is a measured wiring harness with an anti-wave sleeve, and the frequency of the input signal is a preset frequency, and the power is a preset power level;

[0007] measuring a current level I0(f) flowing through the first measured wire bundle and a current level I1(f) flowing through the second measured wire bundle;

[0008] The shielding attenuation S(f) of the aircraft wiring harness anti-wave sleeve is calculated using the formula S(f)=20log(I0(f) / I1(f)).

[0009] Preferably, the step of applying the input signal to the first measured wiring harness and the second measured wiring harness respectively comprises:

[0010] The input signal is applied to the first measured wire bundle and the second measured wire bundle respectively through the signal generator, the power amplifier and the injection probe.

[0011] Preferably, the measuring of the current level I0(f) flowing through the first measured wire bundle and the current level I1(f) flowing through the second measured wire bundle comprises:

[0012] On the spectrum analyzer, the current level I0(f) flowing through the first measured wire bundle and the current level I1(f) flowing through the second measured wire bundle are measured.

[0013] Preferably, the preset frequency ranges from 10 kHz to 400 MHz.

[0014] In a second aspect, the present application provides a shielding attenuation measuring device for an aircraft wiring harness anti-wave sleeve, characterized in that: the device includes a signal injection unit, a measuring unit, and a calculating unit, wherein:

[0015] A signal injection unit, used to apply an input signal to a first measured wiring harness and a second measured wiring harness respectively, wherein the first measured wiring harness is a measured wiring harness without an anti-wave sleeve, and the second measured wiring harness is a measured wiring harness with an anti-wave sleeve, and the frequency of the input signal is a preset frequency, and the power is a preset power level;

[0016] A measuring unit, used to measure a current level I0(f) flowing through the first measured wire bundle and a current level I1(f) flowing through the second measured wire bundle;

[0017] The calculation unit is used to calculate the shielding attenuation S(f) of the aircraft wiring harness anti-wave sleeve by using the formula S(f)=20log(I0(f) / I1(f)).

[0018] Preferably, the signal injection unit comprises: a signal generator, a power amplifier and an injection probe.

[0019] Preferably, the measuring unit includes a spectrum analyzer, a coaxial load, and an attenuator.

[0020] Preferably, the preset frequency ranges from 10 kHz to 400 MHz.

[0021] The advantage of the present invention is that when there is no coupled measuring tube and the three-coaxial method measurement cannot be carried out, aircraft designers and the like can still use the measurement method proposed in the present invention to complete the shielding attenuation measurement of the aircraft wiring harness anti-wave sleeve, and guide the aircraft designers to select a wiring harness anti-wave sleeve that can meet the shielding attenuation requirements and is light in weight and low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the configuration diagram of the current injection test on the tested wiring harness without a surge protector.

[0023] Figure 2 This is the configuration diagram of the current injection test on the tested wiring harness with a surge protector. DETAILED DESCRIPTION

[0024] The present invention proposes a method for measuring the shielding attenuation of an aircraft wiring harness anti-wave sleeve, with a measurement frequency range of 10kHz to 400MHz, characterized in that: a signal of a certain power level is applied to the measured wiring harness without an anti-wave sleeve and with an anti-wave sleeve through a signal generator, a power amplifier and an injection probe, and the current levels I0(f) and I1(f) flowing through the measured wiring harness without an anti-wave sleeve and with an anti-wave sleeve are respectively measured on a spectrum analyzer, and finally the shielding attenuation S(f) of the anti-wave sleeve is calculated using the formula S(f)=20log(I0(f) / I1(f)). The present measurement method can simply and quickly measure the shielding attenuation characteristics of the aircraft wiring harness anti-wave sleeve when there is no coupling measurement tube and the three-coaxial method measurement cannot be carried out, thereby guiding aircraft designers to select a wiring harness anti-wave sleeve that can meet the shielding attenuation requirements and is light in weight and low in cost, and effectively avoiding over-design and under-design of electromagnetic shielding protection of aircraft wiring harnesses.

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0026] In this embodiment, when there is no coupled measuring tube and the three-coaxial method measurement cannot be carried out, the measuring method proposed by the present invention is used to measure the shielding attenuation characteristics of the braided belt anti-wave sleeve with model number 103-027-XXX in the frequency range of 10kHz to 400MHz.

[0027] Before the measurement begins, two test harnesses are made, one is a harness with a length of 1 m and containing two wire cores (i.e., tested harness 8 without a wave-proof sleeve), and the other is a harness with a length of 1 m and containing two wire cores wrapped in a wave-proof sleeve (i.e., tested harness 9 with a wave-proof sleeve).

[0028] The shielding attenuation measurement method of the aircraft wiring harness anti-wave sleeve adopted in this embodiment is:

[0029] Step 1: Follow Figure 1 The test configuration connects the test equipment and the tested wire harness 8 without a wave-proof sleeve, the output port of the signal generator 1 is connected to the input port of the power amplifier 2, the output port of the power amplifier 2 is connected to the input port of the directional coupler 3, the output port of the directional coupler 3 is connected to the injection probe 7, the injection probe 7 is clamped on the tested wire harness 8 without a wave-proof sleeve, one end of the tested wire harness 8 without a wave-proof sleeve is connected to the coaxial load 4, and the other end is connected to the input port of the attenuator 5, the output port of the attenuator 5 is connected to the input port 62 of the spectrum analyzer 6, and the forward power output port 31 of the directional coupler 3 is connected to the input port 61 of the spectrum analyzer 6;

[0030] Step 2: Adjust the signal generator 1 to 10 kHz, without modulation, and increase the applied signal level until the spectrum analyzer 6 displays the forward power level P of the directional coupler 3 corresponding to the input interface 61. w =30dBm;

[0031] Step 3, recording the current level I0(f) flowing through the measured wire harness 8 without the wave-proof sleeve corresponding to the input interface 62 of the spectrum analyzer 6, where f=10kHz;

[0032] Step 4: Scan the signal generator in the frequency range of 10kHz to 400MHz to maintain the forward power level P of the directional coupler 3. w =30 dBm, record the current level I0(f) flowing through the measured harness 8 without the anti-wave sleeve corresponding to the input interface 62 of the spectrum analyzer 6, f∈(10 kHz, 400 MHz];

[0033] Step 5: Follow Figure 2 The test configuration connects the test equipment and the tested wiring harness 9 with the anti-wave sleeve, the output port of the signal generator 1 is connected to the input port of the power amplifier 2, the output port of the power amplifier 2 is connected to the input port of the directional coupler 3, the output port of the directional coupler 3 is connected to the injection probe 7, the injection probe 7 is clamped on the tested wiring harness 9 with the anti-wave sleeve, one end of the tested wiring harness 9 with the anti-wave sleeve is connected to the coaxial load 4, and the other end is connected to the input port of the attenuator 5, the output port of the attenuator 5 is connected to the input port 62 of the spectrum analyzer 6, and the forward power output port 31 of the directional coupler 3 is connected to the input port 61 of the spectrum analyzer 6;

[0034] Step 6: Step 6 is to repeat step 2;

[0035] Step 7, recording the current level I1(f) flowing through the measured wire harness 9 with the wave-proof sleeve corresponding to the input interface 62 of the spectrum analyzer 6, where f=10kHz;

[0036] Step 8: Scan the signal generator in the frequency range of 10kHz to 400MHz to maintain the forward power level P of the directional coupler 3. w =30dBm, record the current level I1(f) flowing through the measured harness 9 with the wave-proof sleeve corresponding to the input interface 62 of the spectrum analyzer 6, f∈(10kHz,400MHz];

[0037] Step 9. Calculate the shielding attenuation S(f) of the anti-wave sleeve at each scanning frequency point in the frequency range of 10kHz to 400MHz as 20log(I0(f) / I1(f)), where S(f) is in dB and f is in MHz. Draw the shielding attenuation curve of the tested anti-wave sleeve in the frequency range of 10kHz to 400MHz.

Claims

1. A method for measuring shielding attenuation of an aircraft wiring harness anti-wave sleeve, characterized in that: The method is used to measure the shielding attenuation characteristics of an aircraft harness anti-wave sleeve when there is no coupling measurement tube and the three-coaxial method measurement cannot be carried out. The method includes: Applying input signals to a first measured wiring harness and a second measured wiring harness respectively, wherein the first measured wiring harness is a measured wiring harness without an anti-wave sleeve, and the second measured wiring harness is a measured wiring harness with an anti-wave sleeve, and the frequency of the input signal is a preset frequency, and the power is a preset power level; measuring a current level I0(f) flowing through the first measured wire bundle and a current level I1(f) flowing through the second measured wire bundle; The shielding attenuation S(f) of the aircraft wiring harness anti-wave sleeve is calculated using the formula S(f)=20log(I0(f) / I1(f)); The step of applying the input signal to the first measured wire harness and the second measured wire harness respectively comprises: applying the input signal to the first measured wire harness and the second measured wire harness respectively through a signal generator, a power amplifier and an injection probe; The measuring of the current level I0(f) flowing through the first measured wire bundle and the current level I1(f) flowing through the second measured wire bundle comprises: measuring the current level I0(f) flowing through the first measured wire bundle and the current level I1(f) flowing through the second measured wire bundle on a spectrum analyzer; The methods specifically include: Step 1, connect the test equipment and the tested wire harness (8) without the anti-wave sleeve, the output port of the signal generator (1) is connected to the input port of the power amplifier (2), the output port of the power amplifier (2) is connected to the input port of the directional coupler (3), the output port of the directional coupler (3) is connected to the injection probe (7), the injection probe (7) is clamped on the tested wire harness (8) without the anti-wave sleeve, one end of the tested wire harness (8) without the anti-wave sleeve is connected to the coaxial load (4), and the other end is connected to the input port of the attenuator (5), the output port of the attenuator (5) is connected to the input port (62) of the spectrum analyzer (6), and the forward power output port 31 of the directional coupler (3) is connected to the input port (61) of the spectrum analyzer (6); Step 2: Adjust the signal generator (1) to 10 kHz without modulation, and increase the applied signal level until the spectrum analyzer (6) displays the forward power level Pw of the directional coupler (3) corresponding to the input port (61) = 30 dBm; Step 3, recording the current level I0(f) flowing through the measured wire harness (8) without the anti-wave sleeve corresponding to the input port (62) of the spectrum analyzer (6), where f=10kHz; Step 4: Scan the signal generator within the frequency range of 10kHz to 400MHz, maintain the forward power level Pw of the directional coupler (3) = 30dBm, and record the current level I0(f) flowing through the measured wire harness (8) without the anti-wave sleeve corresponding to the input port (62) of the spectrum analyzer (6); Step 5, connect the test equipment and the tested wire harness (9) with the anti-wave sleeve, the output port of the signal generator (1) is connected to the input port of the power amplifier (2), the output port of the power amplifier (2) is connected to the input port of the directional coupler (3), the output port of the directional coupler (3) is connected to the injection probe (7), the injection probe (7) is clamped on the tested wire harness (9) with the anti-wave sleeve, one end of the tested wire harness (9) with the anti-wave sleeve is connected to the coaxial load (4), and the other end is connected to the input port of the attenuator (5), the output port of the attenuator (5) is connected to the input port (62) of the spectrum analyzer (6), and the forward power output port 31 of the directional coupler (3) is connected to the input port (61) of the spectrum analyzer (6); Step 6: Adjust the signal generator (1) to 10 kHz, without modulation, and increase the applied signal level until the spectrum analyzer (6) displays the forward power level Pw of the directional coupler (3) corresponding to the input port (61) = 30 dBm; Step 7, record the current level I1(f) flowing through the measured wire harness (9) with the anti-wave sleeve corresponding to the input port (62) of the spectrum analyzer (6), f=10kHz; Step 8: Scan the signal generator within the frequency range of 10kHz to 400MHz, maintain the forward power level Pw of the directional coupler (3) = 30dBm, and record the current level I1(f) flowing through the measured wire harness (9) with the anti-wave sleeve corresponding to the input port (62) of the spectrum analyzer (6); Step 9. Calculate the shielding attenuation S(f) of the anti-wave sleeve at each scanning frequency point in the frequency range of 10kHz to 400MHz as 20log(I0(f) / I1(f)), and draw the shielding attenuation curve of the tested anti-wave sleeve in the frequency range of 10kHz to 400MHz.

2. A shielding attenuation measuring device for an aircraft wiring harness anti-wave sleeve, characterized in that: The device is used in the case where the three-coaxial method measurement cannot be carried out without a coupled measuring tube, and comprises a signal injection unit, a measuring unit, and a calculation unit, wherein: The signal injection unit comprises: a signal generator, a power amplifier and an injection probe; and is used to apply an input signal to a first tested wire harness and a second tested wire harness respectively, wherein the first tested wire harness is a tested wire harness without a wave-proof sleeve, and the second tested wire harness is a tested wire harness with a wave-proof sleeve, and the frequency of the input signal is a preset frequency, and the power is a preset power level; step 1, connecting the test equipment and the tested wire harness without a wave-proof sleeve (8), the output port of the signal generator (1) is connected to the input port of the power amplifier (2), the output port of the power amplifier (2) is connected to the input port of the directional coupler (3), and the output port of the directional coupler (3) is connected to the injection probe. The probe (7) is clamped on the measured wire harness (8) without the anti-wave sleeve, one end of the measured wire harness (8) without the anti-wave sleeve is connected to the coaxial load (4), and the other end is connected to the input port of the attenuator (5), the output port of the attenuator (5) is connected to the input port (62) of the spectrum analyzer (6), and the forward power output port 31 of the directional coupler (3) is connected to the input port (61) of the spectrum analyzer (6); Step 2, adjust the signal generator (1) to 10kHz, without modulation, and increase the applied signal level until the spectrum analyzer (6) displays that the forward power level Pw of the directional coupler (3) corresponding to the input port (61) is 30dBm; Step 5: Connect the test equipment and the tested wiring harness (9) with the anti-wave sleeve, connect the output port of the signal generator (1) to the input port of the power amplifier (2), connect the output port of the power amplifier (2) to the input port of the directional coupler (3), connect the output port of the directional coupler (3) to the injection probe (7), clamp the injection probe (7) on the tested wiring harness (9) with the anti-wave sleeve, connect one end of the tested wiring harness (9) with the anti-wave sleeve to the coaxial load (4), and connect the other end to the input port of the attenuator (5), connect the output port of the attenuator (5) to the input port (62) of the spectrum analyzer (6), and connect the forward power output port 31 of the directional coupler (3) to the input port (61) of the spectrum analyzer (6); Step 6: Adjust the signal generator (1) to 10 kHz, without modulation, and increase the applied signal level until the spectrum analyzer (6) displays that the forward power level Pw of the directional coupler (3) corresponding to the input port (61) is 30 dBm; The measuring unit comprises a spectrum analyzer, a coaxial load and an attenuator; and is used to measure the current level I0(f) flowing through the first measured wire bundle and the current level I1(f) flowing through the second measured wire bundle; step 3, recording the current level I0(f) flowing through the measured wire bundle (8) without the anti-wave sleeve corresponding to the input port (62) of the spectrum analyzer (6), f=10kHz; step 4, scanning the signal generator in the frequency range of 10kHz to 400MHz, maintaining the forward power level Pw of the directional coupler (3)=30dBm, and recording the current level I0(f) flowing through the measured wire bundle (8) without the anti-wave sleeve corresponding to the input port (62) of the spectrum analyzer (6), f∈(10kHz,400MHz]; Step 7, record the current level I1(f) flowing through the measured wire bundle (9) with the anti-wave sleeve corresponding to the input port (62) of the spectrum analyzer (6), f=10kHz; Step 8, scan the signal generator in the frequency range of 10kHz to 400MHz, maintain the forward power level Pw of the directional coupler (3) = 30dBm, and record the current level I1(f) flowing through the measured wire bundle (9) with the anti-wave sleeve corresponding to the input port (62) of the spectrum analyzer (6), f∈(10kHz,400MHz]; The calculation unit is used to calculate the shielding attenuation S(f) of the aircraft wiring harness anti-wave sleeve by using the formula S(f)=20log(I0(f) / I1(f)); the shielding attenuation S(f) of the anti-wave sleeve at each scanning frequency point in the frequency range of 10kHz to 400MHz is calculated as 20log(I0(f) / I1(f)), and the shielding attenuation curve of the tested anti-wave sleeve is drawn in the frequency range of 10kHz to 400MHz.

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