where expertise comes together - since 1996 -

The Largest Open Access Portal of Nondestructive Testing (NDT)

Conference Proceedings, Articles, News, Exhibition, Forum, Network and more

where expertise comes together
- since 1996 -

Tecnatom
Tecnatom has more than 50 years of experience providing services, equipment and systems devoted to NDT testing in several sectors and markets.

1328 views
Technical Discussions
Kris Van de Rostyne
Kris Van de Rostyne
06:30 Mar-28-2003
line driver

Hello,
Some piezoelectric ultrasonic sensors seem to include a so-called 'line-drive transformer'. Can anybody inform me about the function or usefulness of this component, or where I could find more information?
Thanks in advance,
Kris



    
 
 
Paul Meyer
R & D,
GE Inspection Technologies, USA, Joined Nov 1998, 47

Paul Meyer

R & D,
GE Inspection Technologies,
USA,
Joined Nov 1998
47
03:09 Mar-28-2003
Re: line driver
Hi Kris,
A piezoelectric transducer generates an electric charge when it receives an acoustic signal. If the transducer is connected to a long coax cable, the charge is distributed over the cable capacitance, reducing the signal amplitude. The "line driver" that I know is an amplifier with a high ipedance input that is able to generate a much larger signal so that the amplitude is sufficient at the far end of the cable. These are normally used when the cable between the transducer and the instrument is very long (10s of meters)
Also, a transformer may be used to match the impedance of the transducer to that of the cable or instrument but I believe you refer to the device described above.
Paul

: Hello,
: Some piezoelectric ultrasonic sensors seem to include a so-called 'line-drive transformer'. Can anybody inform me about the function or usefulness of this component, or where I could find more information?
: Thanks in advance,
: Kris
.



    
 
 
Uli Mletzko
R & D, Retired
Germany, Joined Nov 1998, 89

Uli Mletzko

R & D, Retired
Germany,
Joined Nov 1998
89
05:56 Mar-30-2003
Re: line driver
: Hello,
: Some piezoelectric ultrasonic sensors seem to include a so-called 'line-drive transformer'. Can anybody inform me about the function or usefulness of this component, or where I could find more information?
: Thanks in advance,
: Kris

Hallo Kris,

a transformer, which is integrated into the housing of a piezoelectric sensor, is acting as a matching network.
It is matching the 'wave resistance' Z of the coaxial cable (e.g. Z = 50 Ohm for cable RG 58) to the complex input impedance (impuls) respective output impedance (echo).
Unfortunately, these two impedances (for input resp. output) might be different, so one has to make a compromise for the matching network.

For details, google for 'high frequency transmission lines', 'impedance matching', 'wave restistance', 'standing wave ratio'. Most of this is related to radio or tv engineering or to rf measuring techniques.

Regards Uli Mletzko
MPA NDT Group,
University of Stuttgart,
Germany


    
 
 
Joerg Schulze-Clewing
Joerg Schulze-Clewing
04:53 Apr-03-2003
Re: line driver
Hi Kris,

A transformer is one option but when it comes to
maintaining the best possible signal-to-noise ratio it
is better to place some of the electronics near the
transducer. In a pulsed application this would be a
pre-amplifier, a T/R switch and maybe even the pulser.

Reason for this is that while a transformer can match
impedances it cannot prevent losses due to the non-
resistive nature of the transducer, at least not in
a short-pulse (wideband) application.

Greetings (groetjes),

Joerg.

: Hello,
: Some piezoelectric ultrasonic sensors seem to include a so-called 'line-drive transformer'. Can anybody inform me about the function or usefulness of this component, or where I could find more information?
: Thanks in advance,
: Kris
.



    
 
 
jayaraman
jayaraman
09:13 Oct-08-2003
Re: impedance transformation in hf radio frequency lines
: : Hello,
Will somebody enlighten me on exponential transformation of impedance in rf feeder lines especially in the context of short wave line transmission?
jayaraman
: Hallo Kris,
.
: a transformer, which is integrated into the housing of a piezoelectric sensor, is acting as a matching network.
: It is matching the 'wave resistance' Z of the coaxial cable (e.g. Z = 50 Ohm for cable RG 58) to the complex input impedance (impuls) respective output impedance (echo).
: Unfortunately, these two impedances (for input resp. output) might be different, so one has to make a compromise for the matching network.
.
: For details, google for 'high frequency transmission lines', 'impedance matching', 'wave restistance', 'standing wave ratio'. Most of this is related to radio or tv engineering or to rf measuring techniques.
.
: Regards Uli Mletzko
: MPA NDT Group,
: University of Stuttgart,
: Germany
.



    
 
 

Product Spotlight

Spot weld inspection with Phased Array – PHAsis.one

The first PAUT spot weld inspection device offering a physical resolution of the spot weld diamete
...
r better than 0.35mm. Precise: more than 700 real UT measurements per spot weld. Easy to go: minimal training required due to the user friendly inspection software. Be sure: safe evaluation due to the imaging result display and automated creation of an evaluation proposal for the spot weld quality.
>

Varex Imaging Large Field of View (FOV) Digital Detector Arrays (DDAs)

A larger FOV DDA can reduce the space and volume of the X-ray inspection system on the factory floor
...
, enable faster scanning times, better throughput and better resolution images at a lower dose. Customers can also save time and money. With these benefits in mind, Varex Imaging has designed a family of large FOV detectors (4343HE, XRD 1611, 4343DX-I, 4343CT) for our industrial imaging customers.
>

Echomac® PA Rail Wheel Tester

MAC introduces two versions of Rail Wheel Testers using ECHOMAC® PA platform based on customer requ
...
irements.
>

Aerospace Systems - Automated Ultrasonic Inspection

USL are specialists in the design and manufacture of turnkey ultrasonic inspection systems for aer
...
ospace applications. From monolithic composites to complex honeycomb structures. This video shows just a few examples of what is possible, find out more at: www.ultrasonic-sciences.co.uk
>

Share...
We use technical and analytics cookies to ensure that we will give you the best experience of our website - More Info
Accept
top
this is debug window
s