Laser Distance Meters

Wether in geodesics, in security systems, production controls or just on the golf corse - the measuring of distances with lasers or laserscanners is well established nowadays. The time - namely the time, the light needs to pass the needed distance - is the value to be determined. This sounds so simple, but it isn't - because the velocity of light is very, very high - it's 2.99792*10⁸ m/s. In consequence one has to deal with very small times. In only one microsecond the passes 300 meters. A high resolution in place therefore demands highest resolution in time.

• Laser distance
• Ultrasonic flowmeter
• Ultrasonic density meter
• Ultrasonic thickness meter
• Magnetostrictive Positioning
• Drift chambers
• Frequency and Phaseshift

The perfect task for a Time-to-DigitalConverter like TDC-GP1 and TDC-GPX !

Pratically the reflection mode is used. Tranceiver and receiver are placed in one device. For the distance to be measured we find d=c*t/2 with c=velocity of light. So if we take a distance of 1 kilometer, the time of flight will be 6.7us. If the resolution has to 1cm we already need a time resolution of 67ps. TDC-GPX driven in M-Mode shows a peak-to-peak resolution very close to this. The resolution can be further improved by averaging without seeing any systematic errors from the TDC.

Have a look at our Application Note AN001_e.pdf (129 KB Nov 2000).

Here the advantages, the TDC brings to you:

• Direct conversion of time to digital values
• Highest resolution: down to 10ps (70ps peak-to-peak)
• Multichannel - the TDC-GP1 has two stop channels, TDC-GPX up to 8 channels
• Multihit-capability - TDC-GP1 can handle 4 Stops, TDC-GPX up to 32 Hits
• High Update rates: TDC-GPX can measure with 200MHz peak rate
• Direct pulse width measurement: TDC-GPX can directly measure the pulse width down to 1.5ns
• Space savings: Single Chip-solution in a small TQFP44 package or TQFP100 package
• Industrial operating range: from -45°C to 100°C.
• 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!)