| 摘要 |
<p>A method and apparatus for measuring the distance between a primary station and a secondary station, each having an antenna for transmitting and receiving continuous wave signals, modulated by a measuring signal, the distance being determined at the primary station as a magnitude proportional to the quotient of the phase difference between the measuring signals of the transmitted and the received signals and the measuring signal frequency. The primary station transmits a continuous wave signal modulated by a measuring signal which in turn can be frequency modulated by the measuring signal frequency. At the secondary station this modulated continuous wave signal is additionally modulated by a marking signal and reflected to the primary station as the receiving signal. At the primary station there is obtained from the filtered mixed product from the signal reflected by the secondary station and a local oscillator signal of the primary station a useful signal which is freed of the continuous wave frequency and the measuring signal frequency. There is obtained from the useful signal by amplitude demodulation an evaluation signal freed from the marking signal frequency. The evaluation signal which is dependent upon the phase difference between the measuring signals of the transmitted and received signals is employed in a regulation circuit for a change of the mean measuring signal frequency of the measuring signal of the transmitted signal such that the mean phase difference between the measuring signals of the transmitted signals and the reflected signals assumes a predetermined value at its steady-state condition.</p> |
