| 摘要 |
<p>A batteryless, portable, frequency divider, consisting of a single resonant circuit consisting of an inductor (L1) and a diode (D1). The resonant circuit detects electromagnetic radiation at a first predetermined frequency and responds to said detection by transmitting electromagnetic radiation at a second frequency that is one-half of the first frequency. The circuit is resonant at the second frequency when the voltage across the diode is zero. The frequency divider is utilized in a presence detection system that uses a tag containing the frequency divider. The system transmits electromagnetic radiation at the first frequency into a surveillance zone, and detects the second frequency to detect the presence of the tag in the surveillance zone.</p> |
