Abstract: A mis-function protection method for mobile phones from RF noise interference includes the steps of: a signal detection circuit provided in a mobile phone, the signal detection circuit being operated to periodically detect a RF signal with a predetermined time period to determine outputting a signal; when firstly detecting no RF signal, no signal output from the signal detection circuit, alternatively when firstly detecting a RF signal, the signal detection circuit being operated to secondly detect the firstly-detected RF signal after a predetermined time; and when secondly detecting none of the firstly-detected RF signal, no signal output from the signal detection circuit, alternatively when secondly detecting the firstly-detected RF signal, the signal detection circuit being operated to output the signal.

Abstract: A Hall elements and magnet assembly for use as a proximity detector includes a magnet, a pole piece mounted to one pole end of the magnet and an integrated circuit having two side-by-side Hall elements, an amplifier, interconnecting wiring providing the difference voltage between the two Hall output voltages at the input of the amplifier, and a Schmitt trigger circuit. The integrated circuit is mounted to the pole piece at the pole end of the magnet. The pole piece is a ferromagnetic member which is thinner in the center than at the periphery for achieving a highly uniform field strength across the surface of the magnet pole end toward reducing the criticality of the position of mounting of the integrated circuit in manufacturing and for extending the range of gap dimensions between a passing ferromagnetic article and the assembly for which proper detection of the passing article can be made to occur.

Abstract: An integrated circuit voltage regulator is of the kind having a pass transistor connected collector-to-emitter between the input V.sub.CC conductor and the regulated-voltage output conductor, a current source circuit supplying a base bias current to the pass transistor and a voltage reference and feedback regulator circuit connected between the output voltage conductor and the base of the pass transistor. A protective circuit against high voltage transients adding to V.sub.CC voltage comprises a transistor connected collector-to-emitter between the pass-transistor base and ground has a resistor paralleling the base-emitter junction, which resistor is resistively coupled to the input V.sub.CC line to shunt away the pass-transistor bias current whenever the V.sub.CC voltage level exceeds a value just under the latch-back breakdown voltage of the pass transistor. A zener diode directly connected across the DC input voltage conduction renders the regulator even more tolerant of high voltage transients.

Abstract: A sweep signal generation system for producing an output sweep signal of very high frequency includes a circuit for generating an input sweep signal, and a phase locked loop which includes a phase detector, a voltage controlled oscillator and a harmonic frequency mixer. The output sweep signal is applied to the harmonic mixer together with a local oscillator signal of fixed frequency, the output from the harmonic frequency mixer being applied to the phase detector together with the input sweep signal. The output from the phase detector is applied to the voltage controlled oscillator to cause the frequency of the output thereof to be swept in accordance with variation of the input sweep signal.