Acoustic emission preamp

N

newb

New Member

• Feb 15, 2004

• #1

someone plz help me with some idea to build an acoustic emission preamp
(voltage general purpose) like the one at
http://www.pacndt.com/index.aspx?go=products&focus=Amplifiers.htm

 

R

Russlk

New Member

• Feb 15, 2004

• #2

There is not "one" at that URL.
"As applications and testing conditions vary along with customers needs, the applicable amplifier is also different. There are different ways to categorize the amplifiers. For example:"

So, how do you catagorize your needs?

 

N

newb

New Member

• Feb 16, 2004

• #3

well i the accoustic emission signal is in microvolts and the freq range is around 1M tats the prob . the gain of the amp should selectable of
20/40/60 db .
something like the one at http://www.pacndt.com/index.aspx?go=products&focus=/amplifiers/voltagepreamps.htm

 

N

newb

New Member

• Feb 17, 2004

• #4

are there ne amplifier ckts that work for input signal of 10u volts

 

R

Russlk

New Member

• Feb 17, 2004

• #5

What is the bandwidth of the signal, and what is the source resistance?

 

N

newb

New Member

• Feb 17, 2004

• #6

Acoustic emission signals are signals from materials like steel or building materials like cement which are emitted before or at the time of cracking.
the preamp will take the signal in from a sensor the input impedence of the amp is ideally 10kohms 15pf, the signal freq ranges from 20-1200khz freq.
ie the input bandwidth is 1Mhz
Now the main problem ,the input signal is of microvolts so how do
i differentiate between the signal and the noise the good preamps hav a noise level of <2u volts like 1220A by Physical Acoustic corp.[/list]

 

R

Russlk

New Member

• Feb 18, 2004

• #7

The thermal noise from your sensor will be: 1.26*10^(-7)*(R)^.5
For a 100 ohm sensor, the noise is 1.26 microvolts at 17 deg C, so the signal to noise is low to start with.

 

N

newb

New Member

• Feb 19, 2004

• #8

wats the solution

 

R

Russlk

New Member

• Feb 19, 2004

• #9

Two ways to reduce noise at the source is: !. reduce the bandwidth 2. reduce the temperature.
The signal to noise can be improved by using a more sensitive sensor. What is your sensor?