| 摘要 |
An improved position determining device using a delay line with energy absorptive terminations at the ends thereof and having a driver transducer coupled to the delay line for producing a traveling wave on the line and a first receiver transducer coupled to the delay line at the distance to be determined. A second receiver transducer, also coupled to the delay line, is displaced from the first receiver transducer by a distance preferably substantially equal to one-quarter wavelength of the traveling wave signal. Each of the receiver transducers detects the direct traveling wave signal from the driver transducer and a traveling wave signal component which is reflected from an end termination. The detected signals from the second receiver transducer are phase-shifted by a 90 DEG phase lag and the phase-shifted signals are combined with the signals detected by the first receiver transducer, whereby the reflected signal components in the combined output signal are effectively eliminated.
|
