theory of radio wave vibration sensorrev2optoelec-engineering.com/tech/theory of radio wave...author...

Confidentia

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Confidential.

Copyright by Opto-Electronic Engineering Corporation. All rights reserved.

At ANT position, x=0. Then equation of transmitter source electromagnetic wave is eq.- 3

The reflected electromagnetic wave is received at ANT x=0 with the phase delay relative to the transmitter source wave. The equation of received electromagnetic wave is eq.- 4

Here, φr is a phase shift by reflection which has π[rad] in the case of ideal metal surface. The distance R(t) is expressed with following equation. eq.- 5

Only assumed that having a mono-tone vibration with frequency fv. Then the received electromagnetic wave is

eq.- 6

3. Detecting method The detecting system is noted below.

Fig.- 2 The detecting system

( )000 2cos)( ϕπ +⋅⋅= tfAtytx

( )( )

( ) ⎟⎟⎠

⎞⎜⎜⎝

⎛++⋅−⋅⋅=

++⋅−⋅⋅=

00

00

000

222cos

22cos)(

ϕϕλππ

ϕϕπ

r

rrx

tRtfB

tRktfBty

( ) ( ) ( )tfRRtRRtR v⋅⋅Δ+=Δ+= π2sin000

( )( )

( ) ⎟⎟⎠

⎞⎜⎜⎝

⎛++⋅−⋅⋅

Δ⋅−⋅⋅=

⎟⎟⎠

⎞⎜⎜⎝

⎛++⋅⋅Δ+⋅−⋅⋅=

0000

000

0000

00

42sin4

2cos

2sin42cos)(

ϕϕλππ

λπ

π

ϕϕπλππ

rv

rvrx

RtfR

tfB

tfRRtfBty

×

ANT

ANT

Diode Mixer

Transmtted wave

Oscilator

Local OscilatorReceived wave

DopplerSignal

Confidential.


The detecting method applies the homodyne detection which has local oscillator frequency f0 same as transmitted wave’s frequency. The homodyne detection applies the mixing operation for the transmitted wave and for the received wave. The equation of detected signal is obtained by multiplying eq.- 3 and eq.- 6, and then is expressed by the following equation such as below.

eq.- 7

Here, replaced the each terms such as the following, eq.- 8

Then eq.- 7 becomes the following with eliminating double high-frequency term 2*f0 eq.- 9

It is shown the process of detecting a mechanical vibration by radio wave in Fig.- 4 with a fringe phenomena of Fig.- 3. It is discussed with more detail at the section 4. Please check them in the next.

( ) ( ) ⎟⎟⎠

⎞⎜⎜⎝

⎛++⋅−⋅⋅

Δ⋅−⋅⋅×+⋅⋅=

×=

0000

000000

det

42sin4

2cos2cos

)()()(

ϕϕλππ

λπ

πϕπ rv

rxtx

RtfR

tfBtfA

tytyty

( ) 0000

0 42sin4

ϕϕλππ

λπ

++⋅−⋅⋅Δ⋅

−= rv RtfR

B

( ) ( )

( ) ( )

( )

( ) ⎟⎟⎠

⎞⎜⎜⎝

⎛+⋅−⋅⋅

Δ⋅−⋅⋅=

−⋅⋅≈

−+++⋅⋅⋅=

+⋅⋅×+⋅⋅=

×=

rv

rxtx

RtfR

BA

BBA

BBtfBA

BtfBtfA

tytyty

ϕλππ

λπ

ϕ

ϕϕπ

πϕπ

000

000

000

00000

00000

det

42sin4

cos21

cos21

cos22cos21

2cos2cos

)()()(

Confidential.


4. Relationship between a fringe phenomena of received signal strength and the distance

When no mechanical vibration has occurred, the eq.- 9 becomes the following. eq.- 10

We examine the relationship with distance parameter R, then we get these results in Fig.- 3. We assumed that A0*B0/2=1. Here, λ0=12.465mm, f0=24.05GHz. So the amplitude of a mechanical vibration is limited up to ±1.5mm.

eq.- 11

Fig.- 3 a fringe phenomena with distance parameter (f0=24.05GHz)

We have to take the relationship about the setting position x=R0 from the radio wave source ANT location to the reflection surface into consideration. The location of R0 affects distortion of the detected signal. That is, the bad position of R0 occur a large distortion for the detected signal. The worst condition about position of R0 converts the detected signal into double frequency 2*fv. So if we want to measure the precise signal shape for the detected signal, we have to adjust the position R0 properly.

⎟⎟⎠

⎞⎜⎜⎝

⎛+⋅−⋅⋅= rRBAty ϕλ

π0

000det

4cos21)(

‐1.5

‐1

‐0.5

0

0.5

1

1.5

‐10 ‐9 ‐8 ‐7 ‐6 ‐5 ‐4 ‐3 ‐2 ‐1 0 1 2 3 4 5 6 7 8 9 10

Normalized

Amplitud

e of detected signal [A.U.]

Relative displacement [mm]

[ ]mmR 5.10 ±≤Δ

Confidential.


Fig.- 4 Process of detecting a mechanical vibration by radio wave

We have to take the relationship about the setting position x=R0 from the radio wave source ANT location to the reflection surface into consideration. The location of x=R0 affects distortion of the detected signal. That is, the bad position of R0 occur a large distortion for the detected signal. The worst condition about position of R0 converts the detected signal into double frequency 2*fv. So if we want to measure the precise signal shape for the detected signal, we have to adjust the position R0 properly. One of the detecting systems is the I,Q-channel type which detects the radio wave signal with orthogonalization by π/2 phase shift. (See Fig.- 5) The fringe phenomena for the detected I,Q-ch signals is in Fig.- 6. We are able to select a proper channel, I-ch or Q-ch in order to get a less distorted signal. Namely the most distorted signal position for I-ch gives the least distorted signal position for Q-ch. Vice versa. See Fig.- 6 carefully. So the way how to avoid getting the distorted signal is to select either proper channel I-ch/Q-ch, or to adjust the location of x=R0 such as by slightly rotating the ANT direction with camera motor platform stage. We are able to discriminate a proper position of distance R0 with maximum amplitude of detected signal ydet with a least distortion.

‐1.5

‐1

‐0.5

0

0.5

1

1.5

‐10 ‐9 ‐8 ‐7 ‐6 ‐5 ‐4 ‐3 ‐2 ‐1 0 1 2 3 4 5 6 7 8 9 10

Normalized

Amplitud



time

time

Detected Signal

Mechanical Vibration

Confidential.


Fig.- 5 I,Q channel type of detector

Fig.- 6 fringe phenomena for the detected I,Q-ch signals

×

ANT

ANT

Diode Mixer

Transmission wave

Oscilator

Local Oscilator Received wave

DopplerSignal I

×

Diode Mixer

Local Oscilator

DopplerSignal Q

π／2

‐1.5

‐1

‐0.5

0

0.5

1

1.5

‐10 ‐9 ‐8 ‐7 ‐6 ‐5 ‐4 ‐3 ‐2 ‐1 0 1 2 3 4 5 6 7 8 9 10

Normalized

Amplitud



I‐ch

Q‐ch

Confidential.


It is going to calculate properly the harmonic components of eq.- 9. Here, φr=π. Then

eq.- 12

It is applied Bessel function formula to eq.- 12. (m = integer) eq.- 13

eq.- 14

Jn(x) is Bessel functions of the first kind. (m,k are positive integer) eq.- 15

Fig.- 7 Bessel function of the first kind

( )

( ) ( )

( ) ( )⎟⎟⎠

⎞⎜⎜⎝

⎛⋅⋅

Δ⋅⎟⎟⎠

⎞⎜⎜⎝

⎛⋅+⎟⎟

⎠

⎞⎜⎜⎝

⎛⋅⋅

Δ⋅⎟⎟⎠

⎞⎜⎜⎝

⎛⋅

−=

⎟⎟⎠

⎞⎜⎜⎝

⎛⋅⋅

Δ−⋅⎟⎟

⎠

⎞⎜⎜⎝

⎛−⋅+⎟⎟

⎠

⎞⎜⎜⎝

⎛⋅⋅

Δ−⋅⎟⎟

⎠

⎞⎜⎜⎝

⎛−⋅

−=

⎟⎟⎠

⎞⎜⎜⎝

⎛⎟⎟⎠

⎞⎜⎜⎝

⎛⋅

Δ+⋅−⋅

−=

tfRRBA

tfRRBA

tfRRBA

tfRRBA

tfRRRBA

ty

vv

vv

v

πλπ

λπ

πλπ

λπ

πλπ

λπ

πλπ

λπ

πλπ

2sin4

sin4

sin2

2sin4

cos4

cos2

2sin4

sin4

sin2

2sin4

cos4

cos2

2sin14

cos2

)(

0

0

0

000

0

0

0

000

0

0

0

000

0

0

0

000

0

0

0

000det

( )( ) ( ) ( ) ( )∑∞

=

⋅⋅+=⋅1

20 2cos2sincosm

m mxJxJx θθ

( )( ) ( ) ( )( )∑∞

=+ +⋅⋅=⋅

012 12sin2sinsin

mm mxJx θθ

‐0.6

‐0.4

‐0.2

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5 6 7 8 9 10

Bessel fu

nction

Jm(x)

x

Bessel function of the first kind

J0

J1

J2

J3

J4

J5

( ) ( )( )km

k

k

mx

mkkxJ

2

0 2!!1 +∞

=⎟⎠⎞

⎜⎝⎛⋅

+⋅−

= ∑

( ) ( )( )km

k

k

mx

mkkxJ

2

0 2!!1 +∞

=⎟⎠⎞

⎜⎝⎛⋅

+⋅−

= ∑

Confidential.


Here we replace each parameter such as following. eq.- 16

eq.- 17

Then eq.- 12 becomes eq.- 18

And then, eq.- 19

a) Case of No vibration ΔR0=0, x=0

If no vibration x=0 occurs and the position R0 = mπ*λ0/ (4π), then we get from eq.- 19. eq.- 20

If no vibration x=0 occurs and the position R0 = (m+1/2)π*λ0/ (4π), then we get from eq.- 19. eq.- 21

That is meaning that J0(x) expresses DC component. And J1(x) expresses fundamental frequency fv of vibration wave, J2(x) is 2nd harmonic vibration 2*fv, J3(x) is 3rd harmonic vibration 3*fv, and so on.

b) Case of which vibration occurs at position R0 = (m+1/2)π*λ0/ (4π) The best position of R0 with a least distorted vibration signal is R0 = (m+1/2)π*λ0/ (4π) as will be noted from Fig.- 4, and gives us the equation eq.- 22 at R0 = (m+1/2)π*λ0/ (4π). eq.- 22

The eq.- 22 includes a fundamental vibration mode with frequency fv expressed by J1(x). The parameter x indicates a depth of vibration strength with ΔR0. When the depth ΔR0 of vibration is increasing with the condition R0 = (m+1/2)π*λ0/ (4π), the a fundamental vibration component is

tf v⋅= πθ 2

0

04λπ R

xΔ

=

( )( ) ( )( )θλπ

θλπ

sinsin4

sin2

sincos4

cos2

)(0

000

0

000det ⋅⋅⎟⎟

⎠

⎞⎜⎜⎝

⎛⋅+⋅⋅⎟⎟

⎠

⎞⎜⎜⎝

⎛⋅

−= x

RBAx

RBAty

( ) ( ) ( )

( ) ( )( )⎭⎬⎫

⎩⎨⎧

+⋅⋅⋅⎟⎟⎠

⎞⎜⎜⎝

⎛⋅+

⎭⎬⎫

⎩⎨⎧

⋅⋅+⋅⎟⎟⎠

⎞⎜⎜⎝

⎛⋅

−=

∑

∑∞

=+

∞

=

012

0

000

120

0

000det

12sin24

sin2

2cos24

cos2

)(

mm

mm

mxJRBA

mxJxJRBA

ty

θλπ

θλπ

( )2

012

)( 00000

detBA

JBA

tymm

=⋅⋅=

( ) ( )( ) 012sin0212

)(0

1200

det =⎭⎬⎫

⎩⎨⎧

+⋅⋅⋅⋅= ∑∞

=+

mm mJ

BAty θ

( ) ( )( )⎭⎬⎫

⎩⎨⎧

+⋅⋅⋅±

= ∑∞

=+

012

00det 12sin22

)(m

m mxJBA

ty θ

Confidential.


increasing simultaneously, but also the harmonic components Jk(x) (odd k>=3) is increasing gradually as will be noted from Fig.- 7.

c) Case of which vibration occurs at position R0 = mπ*λ0/ (4π) The worst position of R0 with no fundamental vibration mode is R0 = mπ*λ0/ (4π) as will be noted from Fig.- 4, and gives us the equation eq.- 23 at R0 = mπ*λ0/ (4π). eq.- 23

The eq.- 23 has DC component, but has no fundamental vibration component fv. When the vibration ΔR0 is increasing, the second harmonic components 2*fv is also increasing gradually as will be noted from Fig.- 7.

d) Case of which vibration occurs at arbitrary position R0 The equation of detected vibration signal at arbitrary position R0 is eq.- 19. So we may resolve the eq.- 19 into each harmonic order term such as the following. The range what we need as the radio wave vibration sensor is up to x=2, so it is enough to take up to 5th-order harmonic component into consideration as will be noted from Fig.- 7. (d-1) DC component term eq.- 24

(d-2) fundamental vibration term fv eq.- 25

strength (amplitude) of signal eq.- 26

(d-3) 2nd order harmonic component term 2*fv eq.- 27


( ) ( ) ( )⎭⎬⎫

⎩⎨⎧

⋅⋅+⋅= ∑∞

=120

00det 2cos22

)(m

m mxJxJBA

ty θm

( )xJRBAty 00

000det

4cos

2)( ⋅⎟⎟

⎠

⎞⎜⎜⎝

⎛⋅

−=

λπ

( ) ( ){ }θλπ

sin24

sin2

)( 10

000det ⋅⋅⋅⎟⎟

⎠

⎞⎜⎜⎝

⎛⋅+= xJ

RBAty

( ) ( ){ }θλπ

2cos24

cos2

)( 20

000det ⋅⋅⋅⎟⎟

⎠

⎞⎜⎜⎝

⎛⋅

−= xJ

RBAty

( )xJRBAVtyofAmplitude st 10

000

max1det

4sin)(__ ⋅⎟⎟

⎠

⎞⎜⎜⎝

⎛⋅+==

λπ

( )xJRBAVtyofAmplitude nd 20

000

max2det

4cos)(__ ⋅⎟⎟

⎠

⎞⎜⎜⎝

⎛⋅−==

λπ

Confidential.


(d-4) 3rd order harmonic component term 3*fv eq.- 29


(d-5) 4th order harmonic component term 4*fv eq.- 31


(d-6) 5th order harmonic component term 5*fv eq.- 33


Now we get some results of the relationship between the received signal strength ΔR0 and the distance R0. And more we are able to know the total harmonic distortion (THD). eq.- 35

Here a root mean square value is defined as the following eq.- 36

We assumed that A0*B0/2 = 1. The effective area as the radio wave vibration sensor is up to ΔR0 = 1.5mm which is indicated in eq.- 11.

( ) ( ){ }θλπ

3sin24

sin2

)( 30

000det ⋅⋅⋅⎟⎟

⎠

⎞⎜⎜⎝

⎛⋅+= xJ

RBAty

( ) ( ){ }θλπ

4cos24

cos2

)( 40

000det ⋅⋅⋅⎟⎟

⎠

⎞⎜⎜⎝

⎛⋅

−= xJ

RBAty

( ) ( ){ }θλπ

5sin24

sin2

)( 50

000det ⋅⋅⋅⎟⎟

⎠

⎞⎜⎜⎝

⎛⋅+= xJ

RBAty

( )xJRBAVtyofAmplitude rd 30

000

max3det

4sin)(__ ⋅⎟⎟

⎠

⎞⎜⎜⎝

⎛⋅+==

λπ

( )xJRBAVtyofAmplitude th 40

000

max4det

4cos)(__ ⋅⎟⎟

⎠

⎞⎜⎜⎝

⎛⋅−==

λπ

( )xJRBAVtyofAmplitude th 50

000

max5det

4sin)(__ ⋅⎟⎟

⎠

⎞⎜⎜⎝

⎛⋅+==

λπ

( ) ( ) ( ) ( )100[%]

1

25

24

23

22 ×

+++= RMS

st

RMSth

RMSth

RMSrd

RMSnd

VVVVV

THD

2

maxorderkthRMS

orderkthV

V −− =

Confidential.


Fig.- 8 Vibration strength ΔR0 and Detected signal amplitude

DC Level=0 at Fig.- 3, Relative Distance R0=λ0/8

Fig.- 9 Total harmonic distortion ratio

DC Level=0 at Fig.- 3, Relative Distance R0=λ0/8

‐0.8

‐0.6

‐0.4

‐0.2

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5

Detected Signal Amplitud

e [A.U.]

Vibration Amplitude ΔR0 [mm]

Detected Signal Amplitude of each harmonic order

1st order

2nd order

3rd order

4th order

5th orderRelative Distance R0 = λ0/8DC level = 0

1st

2nd

3rd

4th

5th

0

10

20

30

40

50

60

70

80

90

100

‐0.8

‐0.6

‐0.4

‐0.2

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5

THD[%

]


e [A.U.]



1st order

THD

Relative Distance R0 = λ0/8DC level=0

Confidential.



DC Level=0.16 at Fig.- 3, Relative Distance R0=(λ0/8)*1.1



‐0.8

‐0.6

‐0.4

‐0.2

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5


e [A.U.]



1st order

2nd order

3rd order

4th order

5th order

Relative Distance R0 = λ0/8*1.1DC level =+0.16

0

10

20

30

40

50

60

70

80

90

100

‐0.8

‐0.6

‐0.4

‐0.2

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5

THD[%

]


e [A.U.]



1st order

THD

Relative Distance R0 = λ0/8*1.1DC level=+0.16

1st 3rd

5th

2nd 4th

Confidential.






‐0.8

‐0.6

‐0.4

‐0.2

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5


e [A.U.]



1st order

2nd order

3rd order

4th order

5th order


0

10

20

30

40

50

60

70

80

90

100

‐0.8

‐0.6

‐0.4

‐0.2

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5

THD[%

]


e [A.U.]



1st order

THD


1st 3rd

5th2nd

4th

Confidential.






‐0.8

‐0.6

‐0.4

‐0.2

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5


e [A.U.]



1st order

2nd order

3rd order

4th order

5th order


0

10

20

30

40

50

60

70

80

90

100

‐0.8

‐0.6

‐0.4

‐0.2

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5

THD[%

]


e [A.U.]



1st order

THD


1st 3rd

5th

2nd

4th

Confidential.



DC Level=1.0 at Fig.- 3, Relative Distance R0=(λ0/8)*2.0 The total harmonic distortion ratio with condition of {DC Level=1.0, R0=(λ0/8)*2.0} is no point because of that no fundamental vib ration fv occurs.

Fig.- 17 Distance R0 and Detected signal amplitude (ΔR0=1.5mm)

‐0.8

‐0.6

‐0.4

‐0.2

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5


e [A.U.]



1st order

2nd oeder

3rd order

4th order

5th orderRelative Distance R0 = λ0/4DC level =+1.0

1st 3rd 5th

2nd 4th

‐1.5

‐1

‐0.5

0

0.5

1

1.5

0 1 2 3 4 5 6 7 8 9 10 11 12


e [A.U.]

Relative Distance R0[mm]


1st order

2nd order

3rd order

4th order

5th order

Vibration Amplitude ΔR0 =1.5mm

1st

2nd

3rd

Confidential.




‐1.5

‐1

‐0.5

0

0.5

1

1.5

0 1 2 3 4 5 6 7 8 9 10 11 12


e [A.U.]



1st order

2nd order

3rd order

4th order

5th order


‐1.5

‐1

‐0.5

0

0.5

1

1.5

0 1 2 3 4 5 6 7 8 9 10 11 12


e [A.U.]



1st order

2nd order

3rd order

4th order

5th order


1st

1st

2nd

Confidential.


Fig.- 20 Total harmonic distortion ratio per Distance R0 (ΔR0=1.5mm)


0

10

20

30

40

50

60

70

80

90

100

‐1.5

‐1

‐0.5

0

0.5

1

1.5

0 1 2 3 4 5 6 7 8 9 10 11 12

THD[%

]


e [A.U.]


Total Harmonic Distortion Ratio

1st order

THD


0

10

20

30

40

50

60

70

80

90

100

‐1.5

‐1

‐0.5

0

0.5

1

1.5

0 1 2 3 4 5 6 7 8 9 10 11 12

THD[%

]


e [A.U.]



1st order

THD


Confidential.



5. How to control the most proper position of distance R0

We can understand the fact that the most proper position of distance R0 exists at the peak of its 1st order fundamental detected signal strength which describes the true vibration signal, as will be noted from Fig.- 20, Fig.- 21, Fig.- 22.

So we are able to realize the best position adjustment of the distance R0 between the Antenna (ANT) of Radio Wave Module and the reflection surface of object by rotating slightly the angle of ANT with camera platform motor stage, or by displacing the distance R0 with linear guide stage in such a way as to get a peak of the 1st order fundamental detected signal like the following figure.

Actually, it is not so hard for us to get the best position of R0, because of that the ANT of Radio Wave Module has a broadening for its radiation characteristics, or of that the general objects have their gradual continuous perspective along the distance, and of that the strength of 1st order fundamental detected signal is most strong than the other harmonic order signals. So, in many general case, the condition for getting the 1st order fundamental detected signal, are coming into effect. Not so severe for us.

0

10

20

30

40

50

60

70

80

90

100

‐1.5

‐1

‐0.5

0

0.5

1

1.5

0 1 2 3 4 5 6 7 8 9 10 11 12

THD[%

]


e [A.U.]



1st order

THD


Confidential.


Fig.- 23 How to get the proper position of distance R0 with slightly adjusting the angle of ANT

6. Differences of the mechanism between radio wave vibration sensor and Doppler radar

When the reflection surface of object moves in a single direction with no restoring force in Fig.- 1 and in Fig.- 3, the Doppler phenomena occurs with going through the fringe of Fig.- 3 such as the following Fig.- 24. We can get the Doppler frequency by calculating the period time of going through one hill of its fringe such as below. eq.- 37

Also we are able to treat the Doppler effect term in eq.- 6 by replacing the parameter such as the following, eq.- 38

The eq.- 6 becomes the following in the case of Doppler phenomena, which is called Doppler Radar equation, Here fdoppler is same to eq.- 37. eq.- 39

0

10

20

30

40

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60

70

80

90

100

‐1.5

‐1

‐0.5

0

0.5

1

1.5

0 1 2 3 4 5 6 7 8 9 10 11 12

THD[%

]


e [A.U.]



1st order

THD


ANT

Adjusting the angle θ of ANT

Best position of R0

Adjusting the angle θ of ANT

[ ] [ ][ ] [ ]

[ ] [ ] [ ][ ]smcs

mHzfs

mm

sm

mTHzf

dopplerdoppler

υυ

λυ

λ⋅⋅

=⋅===0

00

22211

( ) ttfR v ⋅⋅⇒⋅⋅Δ⋅− υλππ

λπ

00

0

42sin4

( )

( ) ⎟⎟⎠

⎞⎜⎜⎝

⎛++⋅−⋅+⋅⋅=

⎟⎟⎠

⎞⎜⎜⎝

⎛++⋅−⋅−⋅⋅=

000

00

000

00

42cos

42cos)(

ϕϕλππ

ϕϕυλππ

rdoppler

rrx

RtffB

tRtfBty

Confidential.


Fig.- 24 Process of Doppler phenomena

7. Our Radio Wave Vibration Sensor System

We can supply our Radio Wave Vibration Sensor System “OEL4232-02” which provides the powerful solutions for measuring the mechanical vibrations and for measuring the velocities of moving objects and for measuring the distances of various objects such as vehicles, buildings with an epoch-making non-contact remote sensing. Please contact our web site.

http://www.optoelec-engineering.com/products/products_en.html [email protected]

Functions １)Monitoring a time-waveform of vibration with displaying on graph ２)Frequency Analysis of vibration by FFT(Fast Fourier Transform) ３)Automatic Area Scanning by camera motor platform with a color toned graph photo of objects per vibration strength shot by digital camera. ４)Measuring a distance to object and velocity of moving object.

‐1.5

‐1

‐0.5

0

0.5

1

1.5

‐10 ‐9 ‐8 ‐7 ‐6 ‐5 ‐4 ‐3 ‐2 ‐1 0 1 2 3 4 5 6 7 8 9 10

Normalized

Amplitud



Velocityυ[m/s]

⎟⎟⎠

⎞⎜⎜⎝

⎛+⋅−⋅⋅= rRBAty ϕλ

π0

000det

4cos21)(

20

0λ

−=R

Confidential.


■Schematics of systems ■Photo

Fig.- 25 our Radio Wave Vibration Sensor System “OEL4232-02”

PlasticCaseBOX

RFantennaANT

RadioWaveModule

DSPControlBoard

miniComputer

(＊)

AC PowerAdaptertripod stand

Application Software CD

PowerSupply

Power Supply；AC 100V Power Adapteror Pb‐Battery 12V＊

CameraMotor Platform＊

Digital Camera＊

＊ ; paid‐for option

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