Method and apparatus for securely enabling a radio communication unit from standby mode

摘要: A radio communication unit employs passive devices and a loop filter to receive coded frequency modulated wakeup or synchronization signal that enables the receiving initiates communications The simultaneously tracks phase provides smoothing enable with weak signals (e.g., typically do not standard locked (PLL) lock). In particular, when is in standby mode, circuits of present invention are energy from antenna initially function as lock onto an incoming signal. includes series tones at different frequencies, where specific sequence prearranged between transmitting units. When each tone has been detected by unit, enabled for communications.