Abstract: A mobile radio communication network including plural radio cells controlled by a centralized hub controller. The hub controller communicates data packets to each radio cell on a data line, and bridges together appropriate audio lines to provide dispatch communications between the radio cells. The hub controller is programmed to carry out tests on each data line and each audio line to verify off-hook conditions thereof so that uninterrupted data signals and audio signals can be carried.

Abstract: The system of the subject invention includes an antenna system, a surface apparatus and a battery-powered remote apparatus useful for applications such as well bore telemetry. In well bore telemetry, the surface apparatus is located uphole on the earth's surface and the remote apparatus is positioned at a remote location downhole in a well bore. The remote apparatus includes a sensor/transmitter unit for sensing physical characteristics such as pressure and/or temperature. The remote apparatus conserves power stored in its battery by transmitting change-in-pressure and/or change-in-temperature data that requires less power for transmission than absolute pressure and/or temperature data. The remote apparatus also conserves power by transmitting absolute pressure data in a single data frame and transmitting absolute temperature data in portions in a series of data frames.

Abstract: The methods of this invention reduce the amount of power consumed by a remotely positioned (i.e. downhole) sensor/transmitter used in applications such as well bore telemetry. The method involves the sensing of physical characteristics such as pressure and/or temperature to generate a first absolute value than is transmitted to a surface receiver located at the earth's surface. At a later time (or period) the physical characteristic is again sensed to generate a second absolute value that is subtracted from the first absolute value to generate a difference. If the difference is significant (i.e., greater than a predetermined value), the difference will be transmitted to the surface receiver. Because the difference will generally have fewer bits of data than the absolute data, less data can be transmitted so that battery power is conserved in the remote sensor/transmitter. In the event that the difference is not significant, even fewer bits need to be transmitted by the remote sensor/transmitter.

Abstract: The present invention comprises an apparatus and method for substantially canceling impulsive noise from data. Such substantial cancellation is achieved by converting the time-domain data into its corresponding frequency spectrum, such that the impulsive noise threshold can be determined. Once such threshold is determined, all frequency components less than this threshold are canceled with the resulting spectrum being converted back to the time-domain. This substantially impulse free signal can then be substituted into the original signal where the impulsive noise occurs, thus, resulting in a signal having minimally distorted data that is substantially devoid of any impulsive noise. This signal may be further processed by an adaptive filter stage to substantially remove any remaining noise from the signal.