Abstract: An implanted medical device (e.g. infusion pump) and handheld communication device communicate with one another via telemetry wherein transmitted messages have enhanced numbers of and/or regularity of bit transitions to minimize the risk of synchronization loss between transmitted bits of data and received bits of data. Bit transitions for portions of messages may be enhanced by applying a pseudo-randomization scheme to those portions of messages that are transmitted in a way that allows the receiver to extract the original data from the received randomized data. Preferred randomization techniques modify (i.e. randomize) the data using a CRC value that is being accumulated while simultaneously causing the modified data to modify subsequent accumulation of the CRC itself. Upon reception, the reversal of data randomization occurs so that the intended message is appropriately received.

Abstract: An RFID system and method for communicating between a host computer, one or more interrogators connected to the host computer, and a large body of transponders distributed within an area covered by the interrogators. Each transponder originally has a common identification code, and upon initialization by the host computer internally generates a unique identification code based upon an internally generated random number. The host, through the interrogators, reads each of the identification codes associated with each transponder by iteratively transmitting a read identification code command along with a controlled variable. Each transponder compares the received controlled variable to an internally generated random number, and selectively transmits its identification code based upon the outcome of this comparison. After the completion of each read identification code iteration, the host adjusts the controlled variable based upon the responses received in the previous iteration.

Abstract: The disclosed spread spectrum system has the reference transmitted on one phase (basis vector) of a .pi./2-offset QPSK signal, and the spread data signal transmitted on another phase (basis vector). The two received phases are combined to recover the baseband signal. Such a transmission system is tolerant to multipath dispersion since all delay paths carry an appropriately delayed reference and signal path induced dispersion on the spread data signal is also present on the reference. If one of the two signals is delayed by a predetermined time interval and a corresponding delay is present in each of two cross-coupled signal processing paths following a conventional I-Q demodulator, the resulting two phase quadrature baseband signals may be combined to form a replica of the original baseband signal. The resultant asynchronous demodulation eliminates the usual requirement for carrier lock at the receiver and is therefore tolerant to Doppler shifts and other frequency errors.

Abstract: An apparatus for controlling both pump displacement of a variable displacement hydraulic pump and the quantity of fuel delivered to an internal combustion engine for the purpose of delivering a requested hydraulic flow at a highly efficient operating point. The apparatus includes an underspeed control means for reducing pump displacement in response to the operating speed of the engine lugging below a desired operating speed. Additionally, a fuel control means operates to reduce the quantity of fuel delivered to the engine in response to the operating speed of the engine rising above the desired operating speed.

Abstract: A speed and direction detector for rotating bodies such as gears (10) including a pair of spaced sensors (14) mounted adjacent the gear teeth (12) to develop phase-shifted alternating signal waveforms, and a decoder (20) to develop a sequence of output signal conditions (S0-S3) depending upon the relation between the alternating waveform values. Signal stage memories (26, 28, 30, 32, 34, 36) utilizing flip-flops and gates connect the decoder outputs to an up/down counter (42, 44) which is incremented or decremented according to gear rotation direction only if a complete signal condition sequence occurs.

Abstract: A method for final assembly of a thrust bearing of the type including an annular roller cage retained within an annular thrust race by means of preformed rigid projections on an outer flange of the thrust race which extend over an outer rim of the roller cage, whereby the roller cage is assembled within the rigid projections by controlled elastic deformation of the parts without any deformation of the rigid projections themselves being necessary.