Abstract: An observed binary code sequence which has been corrupted by noise is operated upon to determine the configuration of a code generator capable of generating an equivalent code sequence. A method and apparatus is introduced to determine the code generator configuration based on rapid testing and elimination of a large set of hypothesis code generator configurations.

Abstract: A method and apparatus for detecting and measuring the code phase offset in bits and fractional bits, or the time delay in master clock cycles, between a reference binary pseudo-noise (PN) code sequence and a similar sequence of unknown delay. Rapid detection and measurement is achieved by utilizing parallel feed-forward logic and eliminating all feedback and variable delay circuitry. At the start of a new detection and measurement cycle, the current state of the A input sequence is stored and correlated with new B input stakes. Likewise the state of the B input sequence is stored and correlated with a new A input code states. After a time equal to the delay between the two input sequences, one of the correlators will produce an output. A time delay counter runs from the start of a new detection and measurement cycle and stops on the occurrence of a correlator output.

Abstract: A spread-spectrum clock circuit is applied to microprocessor or other clocked digital electronic equipment for the purpose of reducing spectral emissions residing at harmonic and subharmonic multiples of the clock frequency. This clock randomly varies the frequency of its output within a frequency constraint bound centered at the average clock frequency. The center frequency of the spread-spectrum clock is stable and is usable for timing and measurement applications. The spread-spectrum clock is a sealed, self-contained circuit module that can be applied to existing digital electronic equipment without modification.

Abstract: In a mobile repeater system there can be two priority repeaters at two adjacent locations which are out of range of each other, but not out of range of each other's portable units. Reception of a tone coded signal from a portable raises the squelch threshold in both repeaters, thus decreasing the portable-to-repeater range without decreasing the repeater-to-repeater range. Interferences caused by simultaneous transmission is eliminated since only the appropriate repeater is activated.

Abstract: A channel priority encoder in a mobile/repeater unit of a two-way communications system allows a low power, detached unit to remotely select a desired channel for high power repeater transmission to and reception from a base station. The selection can be latched-in permanently or can be made to revert to a home channel after a delay. The mobile unit can override a channel selection made by the detached unit, but another mobile unit would provide the repeater function.