Abstract: The effective transmission range of a wireless paging system is varied by changing the transmission data rate. The transmission data rate is lowered in regions with sparse transmitter coverage to increase the effective transmission range of the transmitter. The dual transmission data rates are transmitted either on separate subcarriers on the same FM channel, on the same subcarrier of different FM channels or alternatively on different subcarriers of different FM channels. In a region with dense transmission coverage, the receiver decodes transmission messages at the faster transmission data rate. In regions with sparce transmission coverage, the receiver decodes messages at the slower transmission data rate.

Abstract: A ripple counter becomes programmable by use of intervening circuitry selectively inhibiting state transitions according to an initial programming step. The illustrated embodiment of a programmable ripple counter includes a forward chain of count registers operating generally in the fashion of a ripple counter, but selectively inhibited by an intervening control signal originating from a reverse chain of control registers. By selectively controlling the number of state transitions inhibited and by selectively controlling the number of registers participating in the counting operation, a low power general purpose programmable ripple counter results.

Abstract: A portable communication device which also has an infrared transceiver. A portable communication device can automatically establish infrared communication sessions with another portable communication device or desktop computer having an infrared transceiver. The portable communication device and the other device may exchange textual and graphical information, as well as the current time, and then reconcile the newly received information with that information in possession before the communication session began. Multiple portable communication devices and computers may communicate, while conserving battery power, using a time division multiplexing scheme where the infrared transceivers are active during a short, periodic time slots. Multiple communication session may overlap in time as long as they are not active during the same time slot.

Abstract: Small electronic information storage and display devices such as paging devices with a limited number of control buttons allow user navigation of complex data structures by use of a single control button. Where a user has opportunity to branch within the data structure, the duration of control button actuation determines the selected branch. During the predetermined time interval, the user has visual indication of the item to be next displayed if the user maintains actuation of the control button. In this manner, a single control button supports navigation functions as might normally be established by two buttons such as a cursor right button and a cursor down button. Incorporating a second control button under the present invention supports a cursor left and a cursor up button. In this fashion, navigation of complex data structures occurs naturally and intuitively without requiring more than a limited number of control buttons.

Abstract: A small, high Q loop antenna configured on a printed circuit board as a planar structure receives a radio signal and shields its interior planar area against interfering electric field energy while concentrating therein radio signal magnetic flux. A magnetic pickup loop, coplanar to the antenna loop and magnetically coupled thereto, receives the radio signal power by virtue of its magnetic coupling to the loop antenna. The magnetic pickup loop couples to a receiving device and delivers the radio signal thereto. Illustrated embodiments include loop antennas tunable to a desired resonant frequency.

Abstract: A combined audio receiver and data receiver act in cooperation to serve audio presentation, digital collateral data presentation, and paging functions. The data receiver activates intermittently according to a time-division multiplexed broadcast protocol to receive paging data during brief time slots. At other times, the data receiver tunes to a frequency matching that of the audio receiver to receive digital collateral data descriptive of the audio presentation.

Abstract: Pager data is transmitted at different subcarrier frequencies on different FM broadcast channels. The subcarrier frequency of the pager data is selected to avoid conflicts with signals transmitted from other systems. The pager receiver decodes data at any one of the multiple subcarrier frequencies according to the active subcarrier used on the currently tuned broadcast channel. In one embodiment, the subcarrier frequency of the pager data is contained in control packets of a time division multiplexed data frame. The receiver decodes the control packets to determine which broadcast frequencies and associated subcarrier frequencies contain potential pager signals. The receiver accordingly searches the identified broadcast frequency and automatically reconfigures a circuit demodulator to decode data packets at the identified subcarrier frequencies.

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: Packets are transmitted in different block sizes according to the speed of motion of the receiver. The packet block size is selected to minimize the effects of burst errors that occur at the receiver. The burst errors are disbursed between all packets in the packet block by interleaving the packets together prior to transmission. The receiver then deinterleaves the packets into their original format disbursing burst errors between all packets in the packet block. Since each packet will only contain a small proportion of the burst error, standard ECC schemes can be used to correct for bit errors in each packet increasing the probability that all packets will be transmitted successfully.

Abstract: Integrated circuit components automatically establish or disable a level-pulling condition relative to a given input IC pin as a function of detected signal activity at such IC pin, A logic signal responsive to signal activity at the IC pin drives the gate of a field effect transistor (FET) to dynamically establish or disable level-pulling function at the IC pin. Alternative embodiments include a flop-flop register and an OR gate driving the gate of the FET.

Abstract: A wireless communication system uses transmitted data signals to monitor and control redundant modulator hardware. A modulator unit signature identifying the modulator unit currently transmitting data is embedded into each data frame carried by the transmission signal. Each modulator unit can then independently monitor the transmission signal to determine which modulator is currently transmitting data. Each modulator unit then monitors the transmission signal in case the modulator unit actively generating the transmission signal fails. In a failure situation, the active modulator unit disconnects itself from the transmission circuity while the backup modulator unit independently connects to the transmission circuitry to begin active transmission.

Abstract: A low cost acknowledge-back system for a pager includes a small, portable plug-in module with a telephone connector for coupling to an existing telephone network. Paging devices interact with plug-in modules through a wireless infrared (IR) link. When a paging device comes within communication range of a module, automated interaction therebetween allows the paging device to acknowledge to a paging system successful delivery of a given paging message. The system further includes multiple levels of acknowledgement including acknowledgement of message receipt and message read events at the paging device. Further, the system includes automatic and manual response functions allowing the user of the paging device to initiate automatically or manually a telephone connection using the telephone number of a telephone number message to respond to a given telephone number message.

Abstract: A subcarrier signal generator includes a finite impulse response (FIR) filter responsive to selected FIR coefficients. A first set of FIR coefficients represents an ideal subcarrier shape and center frequency. A calibration step monitors the resulting subcarrier signal and produces a new set of FIR coefficients corresponding generally to the ideal subcarrier signal shape and center frequency, but predistorted according to the compliment of error detected in the actual subcarrier signal. By then loading the new set of FIR coefficients and operating the subcarrier generator, frequency-dependent distortions in the output stage of the subcarrier generator cancel predistortion reflected in the new FIR coefficients. As a result, a high quality subcarrier signal results without use of expensive output stage devices in the subcarrier signal generator.