Abstract: Methods and systems for generating timing signals in remote units which can be used in a radiocommunication system are described. A high accuracy clock can be used to provide a timing reference signal for a processor in the remote unit during times when highly accurate timing signals are required. During periods of low activity, the high accuracy clock can be turned off and a low accuracy clock can be used to generate the reference timing signals for the processor. Periodically, the accuracy of the low accuracy clock can be checked by determining a number of low accuracy clock pulses which are generated between system timing signals created based upon the high accuracy clock pulses. In this way, when the low accuracy clock is relied upon to create the system tuning signals, the accuracy is sufficient to enable the processor to recognize when it is time to again power up the high accuracy clock.

Abstract: A digital system accommodates analog communications, thus avoiding the need for separate subsystems each dedicated to either analog or digital communications. The system includes a receive circuit for converting received signals into an intermediate frequency, a transmit circuit for modulating and transmitting signals and signal processors for processing the intermediate frequency signals and the signals to be transmitted, wherein the signals can be processed into digital or analog format using substantially the same circuitry.

Abstract: A document security article is disclosed in which a light polarizing element is contained within a flexible sheet element. A region of the light polarizing element is exposed at a window at both faces of the sheet element and optionally at a further window at one face of the sheet element. Folding the article to align the windows produces cross polarization between the exposed regions of the light polarizing element.