|
Ultrasonic
Thickness meausrement Non-destructive
testing and material inspection methods like the ultrasonic methods are well established
in production quality control. The control of the thickness of metal layers, pipewalls
or synthetic foils are good examples. The different times of flight for reflected
ultrasonic pulses is is interpretated as material thickness - once again a precise
time measurement is the key: |
| |
|
 The
velocity of sound in aluminium is 5100m/S (bei 20°C). An ultrasonic pulse
is reflected on both, the entry wall and the back wall. Takes as an example a
layer of 1mm aluminium . The difference in travel time for the two reflected pulses
is 2*d/c = 3,9us. For a needed resolution of 0,1% this means a
resolution
of time of 390ps - for the TDC-GP1 no problem! Even
a layer of 10cm aluminium the GP1 can measure with the same absolute resolution! And
see all the advantages of the TDC in this application: - Small
size: Single Chip-solution in the small TQFP44-package
- You
need a broad dynamic range? That's no challenge for our TDC. The GP1 allows
measurements up to 100ms with the high resolution of 110ps - this equals a dynamic
range of 30Bit!!
- Highest
resolution: by averaging - the TDC-GP1 is well suited for this - the standard
deviation can be reduced down to several picoseconds
- Industrial
operating range: from -45°C to 85°C even +100°C is possible.
- Battery
applications: for handheld devices a low current consumption is essential.
Discover the TDC-GP1 - it's perfect for this! When you work in measuring range
2 with only one measurement plus calibration per second, the current consumption
will be only 3uA for a 5V supply (Remarkable: nearly the comlete consumption is
delivered to the calibration clock. If the active period of this clock can be
fitted well, the current consumption can be reduced to nA!)
- Supply
voltage range: 2,7V ....5,5V
- Temperaturemeasurement:
The velocity of sound depends on the temperature. Therefore it's essential
to permanently control the temperature of the fluid. As a temperature measurement
can be reduced easily to a time measurement, we have allready implemented the
necessary functions to the GP1. The RLC-unit allows a reolution of 1°C in
the standard configuration. This value can be easily decreased by the use of some
external components
| |
