| 摘要 |
<p>A responder system in which incoming frequency f0 is converted to a harmonic frequency, e.g. 2f0, by means of a non-linear element, for example a diode, which is connected between the two junctions between capacitance and inductance in two parallel-connected series resonant circuits, one of which is closely tuned to the incoming frequency f0 whilst other is closely tuned to the selected harmonic, e.g. 2f0. Incoming frequency f0 is led to the interconnected ends of the two resonant circuits, whereby both resonant circuits will be excited at their respective resonance frequencies, and the harmonic frequency 2f0 will be radiated back via a common antenna connected to the said interconnected ends of the two series resonant circuits. When transmitting binary information by means of pulses at said harmonic frequency 2f0 the retransmitted pulses can be "marked" in certain pulse intervals by eliminating the resonance condition in the second resonant circuit (2f0) during part of the interval, so that a dip will be produced in the retransmitted pulse, while in other intervals the pulse is retransmitted continuously.</p> |
