Abstract: A method and apparatus authenticates a component (450) for use in a device (100). The device memory (122) stores a predetermined challenge and a predetermined response (212) associated with the predetermined challenge. The method detects whether the component has been coupled to the device. If the component has been detected (206), the predetermined challenge is provided to the component (208). If a component response is received within a predetermined response time (210), it is compared to the predetermined response. The component is disabled (214) if either the component response is not received within the predetermined response time or the component response is received within the predetermined response time but the component response is not equivalent to the predetermined response. The component is enabled (216) if the component response is received within the predetermined response time and the component response is equivalent to the predetermined response.

Abstract: High quality epitaxial layers of monocrystalline materials can be grown overlying monocrystalline substrates by forming a compliant substrate for growing the monocrystalline layers. One way to achieve compliancy includes first growing on a silicon wafer an accommodating buffer layer that is a layer of monocrystalline oxide spaced apart from the silicon wafer by an amorphous interface layer of silicon oxide. The amorphous interface layer dissipates strain and permits the growth of a high quality monocrystalline oxide accommodating buffer layer. In this way, high speed devices can be fabricated along with integral silicon-based circuitry to provide an efficient, low-cost semiconductor structure. Moreover, I/O pins and their associated problems can be eliminated.

Abstract: High quality epitaxial layers of monocrystalline materials can be grown overlying monocrystalline substrates such as large silicon wafers by forming a compliant substrate for growing the monocrystalline layers. One way to achieve the formation of a compliant substrate includes first growing an accommodating buffer layer on a silicon wafer. The accommodating buffer layer is a layer of monocrystalline oxide spaced apart from the silicon wafer by an amorphous interface layer of silicon oxide. The amorphous interface layer dissipates strain and permits the growth of a high quality monocrystalline oxide accommodating buffer layer. The accommodating buffer layer is lattice matched to both the underlying silicon wafer and the overlying monocrystalline material layer. Any lattice mismatch between the accommodating buffer layer and the underlying silicon substrate is taken care of by the amorphous interface layer.

Abstract: An integrated circuit that distributes its clock signals optically is provided. The integrated circuit may preferably include a plurality of digital CMOS circuits that communicate optically. The optical devices are preferably formed from compound semiconductor structures.

Abstract: A composite semiconductor structure includes islands of noncompound semiconductor materials formed on a noncompound substrate, and an optical testing structure. In one embodiment, a scan chain runs through the noncompound substrate (and possibly also through the islands) and terminates in the islands at optical interface elements, one of which is an optical emitter and the other of which is an optical detector. A test device inputs test signals to, and reads test signals from, the scan chain by interfacing optically with the optical interface elements. In another embodiment, an optical detector is formed in the silicon substrate and an optical emitter is formed in the compound semiconductor material. A leaky waveguide communicating with the emitter overlies the detector, and detection by the detector of light emitted by the emitter is an indication of the absence of an intended circuit element between the detector and the leaky side of the waveguide.

Abstract: High quality epitaxial layers of monocrystalline materials can be grown overlying monocrystalline substrates such as large silicon wafers by forming a compliant substrate for growing the monocrystalline layers. One way to achieve the formation of a compliant substrate includes first growing an accommodating buffer layer on a silicon wafer. The accommodating buffer layer is a layer of monocrystalline oxide spaced apart from the silicon wafer by an amorphous interface layer of silicon oxide. The amorphous interface layer dissipates strain and permits the growth of a high quality monocrystalline oxide accommodating buffer layer. The accommodating buffer layer is lattice matched to both the underlying silicon wafer and the overlying monocrystalline material layer. Any lattice mismatch between the accommodating buffer layer and the underlying silicon substrate is taken care of by the amorphous interface layer.

Abstract: The present invention encompasses a base station and method of providing communication services to a plurality of communication units. The method includes the steps of sending communication information between the base station and at least two of the plurality of communication units. A first step of identifying communication units produces a group identifier. A scrambling code, based at least in part on the group identifier, is then used to encode the communication information for transmission.

Abstract: A method and communication device (102) provide multimode communication with multiple autonomous communication systems including a first communication system (104) and a second communication system (106). Resources are dedicated to communication on the respective communication systems. To minimize product cost, resources are shared wherever possible between communication on respective modes. A system supervisor (304) prioritizes, schedules and controls communication between the communication device and the autonomous communication systems.

Abstract: A dual mode communication device (102) includes a first radio (124) operable according to a first mode and a second radio (126) operable according to a second mode. A common user interface (130) controls both the first radio and the second radio. Using two, complete, preexisting radios reduces development and manufacturing costs of the dual mode communication device.

Abstract: A radiotelephone (303) comprises a plurality of subscriber identities (306-308) operative in a radiotelephone system (300) at the same time. The radiotelephone network (301) processes incoming and outgoing calls for the radiotelephone (303) using any one of the subscriber identities (306-308). A standard telephone interface (401) optionally provides communications between the radiotelephone (303) and one or more standard telephone sets (413-415) using any one of the subscriber identities (306-308). A method for operating the radiotelephone (303) is also disclosed.

Abstract: There is provided a method of rapid Received Signal Strength Indication (RSSI) of a time-dispersed signal having echoes (where the time dispersal represents a significant fraction or more of the transmitted symbol interval). It comprises a sliding correlation of a received signal against a known sequence or via channel sounding to obtain the time-dispersal function of the communications channel upon which the signal is transmitted and a summation of the squares of the quadrature components of the energies at relative maxima of the correlations (correlation peaks determined with reference to a threshold level) to integrate the energy defined by the correlation function to determine the energy present among the time-dispersed echoes utilizing the time-dispersal function.

Abstract: A method and associated circuitry for acquiring a channel of a set of frequency channels by a radio receiver. The radio receiver scans selected control channels and measures the power levels of signals generated upon the respective ones of the control channels and stores values. An attempt to effectuate a communication link with a transmitter which transmits a data signal upon one of the control channels is only attempted if the measured power level on such control channel increases beyond a certain amount. The tuning frequency of the tuning circuitry can be retuned when the tuning circuitry is initially tuned to receive a communication signal transmitted by a transmitter of a less-than-most desired network of transmitters according to a second embodiment.

Abstract: A mobile radiotelephone, and associated method, which facilitates usage thereof by a user while also operating an automotive vehicle. The radiotelephone includes a handset having actuation keys of unique geometries permitting the user to identify the keys by tactile rather than visual inspection. A visual-signal display assembly comprised of a heads-up display, including a screen element positionable at a front windshield assembly portion of an automotive vehicle, forms an output display of the radiotelephone, also to facilitate usage of the radiotelephone by a user while also operating the automotive vehicle.

Abstract: A communication unit for use in a communication system is provided which includes a hopping mechanism which hops communication frames over a plurality of carrier frequencies according to a predetermined hopping pattern. At least one of the communication frames preferably includes a synchronization channel time slot having data bits from which the predetermined hopping pattern may be derived. In addition, a communication unit is provided which includes a signal acquisition mechanism for initially acquiring a predetermined hopping pattern that specifies the sequence over which hop frames are hopped over a plurality of carrier frequencies. Also, this communication unit includes a hopping mechanism for hopping receiving frequency according to the predetermined hopping pattern such that a control channel may be detected. In an alternative embodiment, either communication unit may derive the predetermined hopping pattern from detected global position satellite information.

Abstract: The preferred embodiment of the present invention encompasses an automatic frequency control system implemented in a radiotelephone (101). The radiotelephone (101) includes a frequency synthesizer. The frequency synthesizer uses a division ratio varied with time by a multi accumulator fractional N synthesizer (140) such that the effective division ratio may be varied by non-integer steps. The division ratio is programmed to realize the desired channel frequency, the desired modulation waveform, and any automatic frequency correction offset. An accurate clock is provided to the control logic (104) and the user interface (105) sections of the radiotelephone (101) using a second multiple accumulator fractional N division system (139). This second fractional N division system (139) is programmed based on the automatic frequency control programming of the first fractional N synthesizer (140).

Abstract: The present disclosure includes a discussion of a radio receiver. The radio receiver has at least two operational states and includes a variable gain amplifier and at least two adaptive DC offset compensators (421, 427) to suppress undesired DC offset. The first operational state of the radio receiver (121) adjusts the adaptive DC offset compensator circuits (421, 427) to appropriate output levels in absence of an input signal to the radio (121). The second operational state receives the input signal through the radio receiver (121) and eliminates the undesired DC offset (309) from the received input signal with the adaptive DC offset compensator circuits (421, 427) and allows the received input signals to be processed.

Abstract: A low pass filter circuit for a radiotelephone which filters harmonic, spectral components of a modulated signal generated by the radiotelephone. The filter circuit is comprised of inductors and capacitors wherein each inductor and each capacitor of the filter is comprised of a distributed-element portion and a discrete-element portion. The distributed element portions of each inductor and each capacitor of the filter attenuate higher-frequency, spectral components of a signal applied thereto. The discrete element components of each inductor and each capacitor of the filter attenuate lower-frequency, spectral components of the signal applied thereto.

Abstract: A latched accumulator fractional-N synthesizer having reduced residual error for use in digital radio transcievers is disclosed. The divisor of the frequency divider (103) of the synthesizer is varied with time by the summation of accumulator carry output digital sequences which result in frequency increments equal to a fraction of the reference frequency. The accumulators (615,617) are latched such that upon the occurrence of a clock pulse, data is transferred through each accumulator one clock pulse step at a time, such that the delay through the system is equal to that of only one accumulator. The latched output of the second highest order accumulator (619) is subtracted from the latched output of the highest order accumulator (621) and differentiated before being applied to the loop filter (109).

Abstract: A multiple latched accumulator fractional-N synthesizer for use in digital radio transceivers is disclosed. The divisor of the frequency divider (103) of the synthesizer is varied with time by the summation of accumulator carry output digital sequences which result in frequency increments equal to a fraction of the reference frequency. The accumulators (615, 617) are latched such that upon the occurrence of a clock pulse, data is transferred through each accumulator one clock pulse step at a time, such that the delay through the system is equal to that of only one accumulator. The carry outputs of each accumulator are coupled through delays (645, 647, 649, 631, 633) equal to one less delay than the number of accumulators and added (635) such that all higher order accumulator carry outputs add to a net summation of zero so as to not upset the desired fractional setting of the first accumulator.

Abstract: A fractional-N synthesizer employing at least a second order sigma-delta modulator is disclosed. The most significant bits from the output accumulator of the sigma-delta modulator are used as the carry out control for the variable divisor of the loop divider. Modulation to the synthesizer is introduced as part of the digital number input to the sigma-delta modulator and spurious signal output is reduced by selection of a large number as the denominator of the fractional portion of the loop divider divisor.