| 摘要 |
<p>Ultrasonic measuring apparatus comprising interrogation means (4, 5) for transmitting an ultrasonic first signal; transponder means (6) for receiving said signal from said interrogation means and for transmitting a further signal in response thereto; receiving means preferably forming part of said interrogation means (4, 5) for receiving said further signal; and timing means (3) coupled to said interrogation means and arranged to time the time interval betweentransmission of said first signal by said interrogation means and receipt of said further signal by said receiving means. Other disclosed embodiments use transmitters and receivers for distance and position determination with use of a transponder. The invention is applicable to adjusting the stereo balance of a stereo reproduction system as a listener changes his position, in order to maintain the stereo effect and to position location systems for use in robotics.</p> |
