| 摘要 |
A system is provided that can automatically and continuously maintain an inductive-capacitive (LC) network at resonance while the frequency of an excitation signal 209 is varied between a number of discrete frequencies. The system permits the use of frequency modulation or frequency shift keying (FSK) to carry data in near field communication systems, including biomedical devices and wireless charging systems, while using a high-Q resonant antenna coil. The system automatically compensates for manufacturing tolerances and drift of component parameters due ageing and environmental factors. The error between the resonant frequency of the tuned circuit and the excitation frequency is determined in real time from signals within the system. The system may also be used to maintain the LC circuit at resonance while the excitation frequency is varied on a cycle-by-cycle basis between a number of discrete frequencies 1013-1014-1015, the effect of which is to permit phase modulation in discrete phase increments, or phase shift keying (PSK). The system allows the use of high Q antenna coils and fast phase modulation of the transmitted carrier signal. Such a scheme has the advantage of allowing substantially continuous power transfer. |
