Abstract: A polymer comprises the polymerized product of monomers comprising an acid-deprotectable monomer, a base-soluble monomer, a lactone-containing monomer, and a photoacid-generating monomer; a chain transfer agent of the formula; wherein Z is a y valent C1-20 organic group, x is 0 or 1, Rd is a substituted or unsubstituted C1-20 alkyl, C3-20 cycloalkyl, C6-20 aryl, or C7-20 aralkyl; and optionally, an initiator.

Abstract: Heterocycles, e.g., epoxides, are carbonylated at low pressure with high percentage conversion to cyclic, ring expanded products using the catalyst where L is tetrahydrofuran (THF).

Abstract: Catalysts and methods for the carbonylation of epoxides to substituted 3-hydroxy-?-lactones and ?-lactones are disclosed.

Abstract: A packet data transmission system is disclosed in which remote units, such as remote hand-held data gathering units, which normally communicate with remote base stations via a spread spectrum RF communications, are initialized via spread spectrum RF communications. A network chipping sequence is provided for encoding normal communications and an universal chipping sequence is provided for encoding communications relating to initialization of the remote units. The network chipping sequence is adjustable and must be initialized in each of the remote units to enable normal communications. The universal chipping code is fixed for all remote devices and base stations. Since the universal chipping code is fixed, spread spectrum RF communications of the initialization data, using the universal chipping code, can be effected even if the network chipping sequence is not initially set in the remote units.

Abstract: A packet data transmission system is disclosed in which remote units, such as remote hand-held data gathering units, which normally communicate with remote base stations via a spread spectrum RF communications, are initialized via spread spectrum RF communications. A network chipping sequence is provided for encoding normal communications and a universal chipping sequence is provided for encoding communications relating to initialization of the remote units. The network chipping sequence is adjustable and must be initialized in each of the remote units to enable normal communications. The universal chipping code is fixed for all remote devices and base stations. Since the universal chipping code is fixed, spread spectrum RF communications of the initialization data, using the universal chipping code, can be effected even if the network chipping sequence is not initially set in the remote units.

Abstract: A packet data transmission system is used to link a number of remote hand-held data-gathering units such as bar code readers to a central computer which maintains a database management system. Data packets are sent from the remote units by an RF link to intermediate base stations, then sent by the base stations to the central computer by a serial link. Direct sequence spread spectrum modulation is used for the RF link. The remote hand-held units initiate an exchange using RF transmission to and from the base stations, receiving only during a rigid time window following a transmission from the remote unit. The base stations cannot initiate communication to the remote units, but instead send data to the remote units only as part of the exchange.

Abstract: A packet data transmission system is disclosed in which remote units, such as remote hand-held data gathering units, which normally communicate with remote base stations via a spread spectrum RF communications, are initialized via spread spectrum RF communications. A network chipping sequence is provided for encoding normal communications and a universal chipping sequence is provided for encoding communications relating to initialization of the remote units. The network chipping sequence is adjustable and must be initialized in each of the remote units to enable normal communications. The universal chipping code is fixed for all remote devices and base stations. Since the universal chipping code is fixed, spread spectrum RF communications of the initialization data, using the universal chipping code, can be effected even if the network chipping sequence is not initially set in the remote units.

Abstract: A packet data transmission system is used to link a number of remote hand-held data-gathering units such as bar code readers to a central computer which maintains a database management system. Data packets are sent from the remote units by an RF link to intermediate base stations, then sent by the base stations to the central computer by a serial link. Direct sequence spread spectrum modulation is used for the RF link. The remote hand-held units initiate an exchange using RF transmission to and from the base stations, receiving only during a rigid time window following a transmission from the remote unit. The base stations cannot initiate communication to the remote units, but instead send data to the remote units only as part of the exchange.

Abstract: A radio transceiver for use in data communications uses a single phase-locked loop to control the frequency of the receiver portion while simultaneously providing coarse control of the frequency of the transmitter portion. The output of the receiver portion is also used to provide an error signal for fine tuning the transmitter frequency after the component of the error signal caused by modulation of the transmitter portion has been removed.

Abstract: The invention is directed to a remote equipment control system having a low duty cycle communications link between a remote command transmitter and a remote receiver. The remote receiver is controllingly coupled to the equipment. The remote command transmitter includes a means to transmit a message signal of set time duration at a preselected message separation interval. The message signal has a unique address portion and a command portion.The remote receiver includes a decoding unit and a timing circuit. The decoding unit is responsive to the unique address portion of a received message to provide an enabling signal to be delivered to the timing circuit. The timing circuit upon receipt of the enabling signal provides an output to the decoding unit to prevent entry of any message signal to the decoder for a time duration matching the preselected message separation interval and allowing entry of a message signal for a time duration matching the time duration of the message signal.

Abstract: This disclosure relates to an inductively powered type of electronic transponder for identifying a moving object passing an interrogation area. The transponder includes a tuned inductive-capacitive pick-up circuit for receiving interrogating signals. The picked up interrogating signals are rectified to produce d.c. operating power and are applied to a frequency divider for producing a frequency related transmission signal and clock data rate pulse. A latching circuit enables a shift register so that the clock pulses serially shift out binary encoded data from the shift register. The encoded data is fed to a logic network which is coupled to a balanced switching amplifier for phase modulating the transmission signal for propagation into the interrogation area.