Abstract: A phase locked loop circuit employing a single phase detector provides limited maximum lock time by avoiding hang-up. The circuit first establishes a gross indication of phase relation sufficient to establish a direction of phase shift away from the unstable equilibrium point. The phase is then shifted by a predetermined value to establish a bounded phase relation exclusive of the unstable equilibrium point and inclusive of the stable equilibrium point. Conventional phase locking then provides the desired frequency and phase relation, but without potential for hang-up.

Abstract: Backlash in a fishing reel is eliminated by automatically matching the reel discharge speed to the line speed. The drag on the reel is automatically adjusted so that the reel discharge speed does not exceed the line speed. The invention includes a reel, a mechanism for measuring the relationship between the line speed and the reel discharge speed, an electronically controlled braking device and a microprocessor for controlling the braking device in response to the relationship between the line speed and the reel discharge speed. When the reel discharge speed exceeds the line speed additional braking is applied. One alternative embodiment of the invention intermittently applies a very short pulse of braking action to the reel. The response to this pulse of braking action is detected and used to determine if the reel discharge speed exceeds the line speed.

Abstract: A paging device in combination with an accurate stopwatch includes a stopwatch timer block supported by latent processor element resources. The user directly manipulates, e.g., starts and stops, the timer block without processor element intervention. The processor element is thereby free to service higher priority tasks, e.g., receipt of paging information, and collects stopwatch timer block data at a lower priority level.

Abstract: Integrated circuit design contemplating alternate applications incorporates devices, e.g. a gatable pull-down FET resistor, responsive to signal activity at an integrated circuit pin. Signal activity, as opposed to traditional configuration mechanisms, dictates integrated circuit functions including level-pulling functions and bus configuration functions.

Abstract: An improved method and apparatus for automatically tuning an antenna includes adaptive antenna tuning based on a current radio reception frequency and on prior antenna tuning cycles to establish a predictor value. The predictor value establishes an antenna tuning voltage sub-range most likely to contain the optimum antenna tuning voltage, but is a smaller range than the full antenna tuning voltage range. The antenna tuning voltage sub-range is then traversed while monitoring a signal strength indicator to identify an antenna tuning voltage providing optimum tuning conditions. Because only a sub-range of the full antenna tuning voltage range need be traversed, by virtue of the predictor value, relatively small increments in antenna tuning voltage may be used in traversing this sub-range. As a result, the execution time and accuracy of the antenna tuning method of the present invention is improved relative to prior automatic antenna tuning methods.

Abstract: In a time keeping system providing time of day by radio signal to remote time keeping devices, the transmitted time of day is provided in association with a given time zone identification. The time keeping devices receiving the time of day reference and the time zone identification include a time zone preference identification. By comparing the time zone preference and the time zone identification transmitted, the time keeping device can, when necessary, offset the received time of day value according to user preference for display relative to a preferred time zone.

Abstract: A paging system where messages are numbered before they are transmitted. The paging receivers in the system compare both the number and the text information in each message which is received to the message number and the text information in the most recently received previous message. The comparison is used to determine if the same message was previously received and if the any messages were missed. The receiver includes an icon which is turned on to indicate if a message has been received. The icon is set to a blinking state if a message is received and if there is a break is the sequence of message numbers indicating that a message has been missed.

Abstract: A voice mail system includes method and apparatus for muting a previously recorded audio signal upon detection of a DTMF signal to differentiate between recorded DTMF signals and valid DTMF commands. A DTMF signal detected after muting is recognized as an invalid command.

Abstract: The present invention is a magnetic tape-based "voice mail" multi-user message system. The system transmits audio prompts to callers to help guide them through the various procedures. The callers respond with Touch-Tone commands. A novel circuit is provided to detect these tone commands without significant interference from the audio prompt signals. This circuit is highly insensitive to deviations in the impedance of the incoming telephone line from its expected value. A circuit is also provided to prevent Touch-Tone commands which are recorded on tape from being re-executed when they are played back from the tape. A single L.E.D. indicator on each recipient's telephone set indicates the status of the system: idle with new message waiting; idle without new message waiting; busy with new message waiting; or busy without new message waiting.