Abstract: A radio range finding system includes a radio range finder and a plurality of remote mobile transponders. The radio range finder transmits a signal modulated with an address code identifying a particular mobile transponder. When a mobile transponder receives the modulated signal M.sub.s transmitted by the radio range finder and the modulated signal has been modulated with an address code that corresponds to the address assigned to that mobile transponder, the mobile transponder transponds a return signal R.sub.s to the radio range finder. A receiver in the radio range finder conveys the received signal to a mixer which also receives an internal carrier signal identical to the modulated signal output by transmitter. The output of the mixer is then filtered and demodulated to yield an output signal proportional to the distance between the mobile transponder and the radio range finder.

Abstract: An intelligent wall switch incorporates a passive infrared sensor and a pressure pulse-wave sensor. A microcontroller monitors the sensor signals generated by the infrared sensor and the pressure pulse-wave sensor and calculates a weighted sum of the signals generated by the sensors. If the weighted sum calculated by the microcontroller exceeds a preset threshold the intelligent wall switch generates a signal indicative of human presence.

Abstract: A power supply for controlling average power to a load, such as an electric light, heater or motor, comprising a solid state switch connected in series with the load, a power supply connected in parallel with the solid state switch, and a control circuit connected intermediate the power supply and solid state switch for causing the solid state switch to conduct current through the load for a predetermined portion of each AC power cycle. The power supply collects charge whenever the solid state switch is non-conducting. According to the preferred embodiment, a current overload detector and zero crossing detector are also provided for increased reliability and precise definition of the solid state switch conduction timing.

Abstract: A system for adaptive self-tuning of a receiver in a radio communication system. Prior to transmission of each data packet from a transmitter to a receiver, the transmitter generates a sequence of predefined test bytes (test sequence) n times at an initial carrier frequency. An identical version of the predefined test sequence is stored in the receiver. Circuitry is provided in the receiver for selected predefined states of tuning impedances for varying the center operating frequency of the receiver, wherein the predefined states of tuning impedances are equal in number to the predefined number of test sequences. A microcontroller in the receiver compares the received test sequence with the stored test sequence and creates a tuning table correlating respective states of the receiver tuning impedances with error bits detected in each state.

Abstract: A system for adaptive self-tuning of a receiver in a radio communication system. Prior to transmission of each data package from a transmitter to a receiver, the transmitter generates a sequence of predefined test bytes (test sequence) n times. An identical version of the predefined test sequence is stored in the receiver. Circuitry is provided in the receiver for selected predefined states of tuning impedances for varying the center operating frequency of the receiver, wherein the predefined states of tuning impedances are equal in number to the predefined number of test sequences. A microcontroller in the receiver compares the received test sequence with the stored test sequence and creates a tuning table correlating respective states of the receiver tuning impedances with error bits detected in each state.