Hewlett-Packard Company

Seiko Epson Corporation

Eride,. Inc.

Sielox Systems, Inc.

Trimble Navigation Limited

Checkpoint Systems, Inc.

France Rode

Paul W McBurney

Arthur N Woo

Allen Jay Baum

Thomas E Osborne

Peter D Dickinson

David S Cochran

Alexander D Walker

William L Crowley, Jr

Peter Lindes

Ralph F Eschenbach

Zvonko A Fazarinc

Anthony F Piccoli

Charles A Walton

Eric A Slutz

Ali Bologlu

Chung C Tung

A hybrid navigation satellite receiver and mobile telephone uses only two crystal oscillators. One that operates a master clock around 27-MHz and that consumes milliwatts of power. The other oscillator consumes only microwatts of power and operates continuously on battery power at about 32-KHz. Only the second, low frequency oscillator is kept running during power 'off'. On power 'restart', a real-time-clock counter is consulted to cause an estimate of the GPS system time to be regenerated and supplied to the GPS-DSP to quicken its initialization. The master clock is GPS-calibrated, and the accurate clock is used to drive NCO's for the mobile telephone part and host CPU.

Keeping accurate time for a hybrid GPS receiver and mobile phone when powered off

Device and method for minimizing the number of crystal oscillators used in an integrated navigation receiver and cellphone

A navigation-satellite receiver comprises high-sensitivity radio frequency front-end and navigation processor associated with a client CPU. The client CPU runs an operating system that serially communicates with the navigation processor. The client CPU is also able to obtain navigation data system transmissions from a network server and provides such when the direct satellite signals in the high-sensitivity environment are too weak to be demodulated directly. A low power, low frequency oscillator with a watch-type crystal and counter are used as a real time clock to keep time uncertainty under fifty milliseconds when the receiver is hibernating. If the time uncertainty and position uncertainty are below certain maximums when the receiver is re-awakened, then a minimum number of satellites will be needed and making a preliminary z-count to each can be avoided.

Skipping z-counts and accurate time in GPS receivers

A communication system, method, and multiple master and slave transceivers having automatic addressing and collision avoidance. A master transceiver is programmed with its address by a user through a host. After being turned on, a slave transceiver acquires its address as the address of the first message it receives from a master transceiver. The master and the slave transceivers then communicate in each direction and ignore other messages by using that address until the slave transceiver is turned off. When the slave transceiver is turned on again, it acquires a new address of the address of the first new message it receives from a master transceiver, not necessarily the same master transceiver. The transceivers communicate with a signal having an on-condition having different lengths for representing different symbols. A transmitting transceiver detects a collision when it detects a signal on-condition during the longer of the different lengths while it is transmitting a signal on-condition of the shorter of the different lengths.

Communication system having automatic addressing

A security tag is disclosed for use with an electronic security system for a controlled area. The tag comprises circuitry for initially establishing a resonant circuit having a first resonating frequency within a first frequency range which is outside of the range of the detection frequency of the electronic security system. The tag is activated by changing the resonating frequency of the resonant circuit to a second frequency within the detection frequency range by exposing the resonant circuit to electromagnetic energy within the first frequency range at the predetermined minimum power level to short-circuit a first circuit component. The tag is deactivated by again changing the resonant frequency of the resonant circuit to a third resonant frequency within a third frequency range which is also outside of the detection frequency range by exposing the resonant circuit to electromagnetic energy within the detection frequency range of at least a predetermined minimum power level to short-circuit a second circuit component.

Activatable/deactivatable security tag for use with an electronic

An identification system in which power drain is minimized is disclosed. The system comprises a reader (10) including a first signal generator (12) for generating a first signal (F1) which is then radiated by an antenna (17). An identifier (11) is shown which includes an antenna (20) for receiving the first signal for transmission to a signal modulator (32) which operates to modulate the first signal in accordance with a preassigned code for the identifier. The modulated signal is then used to periodically unload or change the reactance of the antenna (20) which action in turn changes the reactance of the reader antenna (17) and the consequent voltage on the reader antenna. By detecting the change in the voltage on the reader antenna the code of the identifier is determined. Power is used efficiently by low frequency oscillation within the signal modulator, by unloading during modulation, and by changing circuit reactance without changing the circuit load.

Electronic proximity identification system

An electronic security system and an electronic proximity key for use therein are disclosed in which a multitiered distributed architecture is used to rapidly and flexibly provide ingress and egress through a plurality of electronic locks. In the event of loss of communication with the central processor, the system will continue to function at lower levels of security without interrupting requests for ingress and egress, and will continue to provide alarm monitor processing. An improved proximity key for actuating the security system is disclosed which includes coupling coils that are integrally formed as part of the integrated circuit lead frame associated with the coding circuitry of such key.

Electronic lock and key system

The present invention provides programmable, remote and automatic numeric control and calibration of analog signal measuring and generating apparatus. Digital values for control signals for control of gain, sensitivity, frequency and the like and for calibration are stored and may be easily modified to follow complex control and calibration functions. Conventional controls are replaced by pushbuttons which initiate calculation of digital control signals for controlling the transfer function of variable elements of the apparatus. Conventional meters and dials are replaced by digital readout devices for indicating operational parameters such as amplitudes, sensitivities, frequencies and the like. Digital values for calibration factors and parameter control settings also may be recorded on suitable recording media for use under recurring conditions and environments.

Method and apparatus for programmable and remote numeric control and

The present invention provides programmable, remote and automatic numeric control and calibration of analog signal measuring and generating apparatus. Digital values for control signals for control of gain, sensitivity, frequency and the like and for calibration are stored and may be easily modified to follow complex control and calibration functions. Conventional controls are replaced by pushbuttons which initiate calculation of digital control signals from controlling the transfer function of variable elements of the apparatus. Conventional meters and dials are replaced by digital readout devices for indicating operational parameters such as amplitudes, sensitivities, frequencies and the like. Digital values for calibration factors and parameter control settings also may be recorded on suitable recording media for use under recurring conditions and environments.

A battery-powered hand-held calculator for performing arithmetic, trigonometric, and logarithmic functions and displaying the results thereof is provided with the capability of automatically storing the last displayed number in an auxiliary storage register whenever the next succeeding function to be performed would destroy that number. That number may be recalled from the auxiliary storage register by simply depressing a prefix key and a Last-X function key.

General purpose calculator having selective data storage, data

The battery powered hand-held calculator for performing the arithmetic, trigonometric and logarithmic functions disclosed herein includes a factorial function which conveniently calculates factorials of positive integers.

General purpose calculator having factorial capability

A battery powered hand-held calculator for performing arithmetic, triganometric and logarithmic functions and displaying the results thereof is provided with a clock mode which performs the function of a clock and displays real time or the function of a stopwatch and stores and displays the times at which recorded events have taken place.

Growing community of inventors

Los Altos, CA, United States of America

France Rode