Abstract: A digital audio broadcasting (DAB) system includes a radio-frequency (RF) transmitter and a corresponding RF receiver. The RF transmitter formats a DAB signal into a sequence of frames, each frame having a header comprising a predefined grouping of psuedo-random number sequences comprising 100 symbols. Of these 100 symbols, 86 symbols of the header are used for frame synchronization and channel sounding (for characterization of a communications channel), while the remaining 14 symbols are used for interleaver and data synchronization in an interleaved fashion.

Abstract: An acoustic signal receiving apparatus comprising a housing having an acoustically reflecting surface and a directional acoustic sensor unit having first-order gradient characteristics. The sensor unit is coupled to the housing with use of a retractable member having a retracted position and an extended position. When the member is extended, the sensor unit is positioned relative to the reflecting surface such that the acoustic interaction between the sensor unit and the reflecting surface causes the output of the sensor unit to have second-order gradient response characteristics. In accordance with one illustrative embodiment, in a notebook computer with a "flip-back" lid, the sensor element automatically extends to the desired position when the lid is opened, and automatically retracts to be flush with the housing surface when the lid is closed.

Abstract: A circuit for, and method of, generating a cryptographic key at a communications node. The circuit includes: (1) communications circuitry for communicating a first seed during a first communications session and communicating a second seed during a second communications session temporally separated from the first communications session and (2) processor circuitry for creating the cryptographic key from the first and second seeds, the communicating of the first and second seeds occurring during the temporally-separated first and second communications sessions, respectively, thereby to enhance a privacy of the cryptographic key.

Abstract: A silicon-on-silicon dual MCM apparatus comprising a printed circuit board having a voltage isolation boundary contained therein supporting a pair of multi-chip modules on either side of the voltage isolation boundary. The MCMs safely convey signals across the isolation boundary via discrete optical coupling means or the like. The optical coupling means allow safe and efficient conveyance of signals across the voltage isolation boundary enabling a designer to group high voltage components on one side of the boundary and low voltage components on the other side of the boundary. This obviates to a degree the need for multi-layered PCBs. A relatively large number of passive components (resistors and capacitors) are integrated into a silicon substrate with flip-chip analog integrated circuits (ICs). Operational characteristics of the controller are verified after integration and are compared to the discrete version.

Abstract: This application describes a new method for rapid thinning, planarizing and fine polishing surfaces of diamond to the submicron/nanometer level so that large area, uniform thickness diamond wafers can be obtained. The method combines both chemical (dissolution of carbon in molten metals) and mechanical (rotating or moving sample fixtures in contact with the dissolving metals) polishing to achieve flat, smooth surface finishes in a relatively short period of time, thus improving the quality and economics of the overall polishing process. Several embodiments of apparatus for performing such chemical-mechanical polishing (CMP) of diamond are described.

Abstract: The specification describes a discriminating photodiode for detection of 1.55 .mu.m signals used in wavelength multiplexed systems operating with 1.3 .mu.m and 1.55 .mu.m wavelengths. The device uses a semiconductor layered structure to absorb photons from the 1.3 .mu.m signal, and annihilate the photogenerated carriers, while passing the 1.55 .mu.m light to a photodetecting junction beneath the layered structure.

Abstract: Briefly, in accordance with one embodiment of the invention, a coarse frequency burst detector for use at the receiving end of a wireline communications system comprises: a digital signal filter adapted to filter a component of decoded signal samples, the decoded signal samples being derived from a baseband signal transmitted via the wireline communications system; and a threshold detector adapted to threshold the signal level of the filtered component of the decoded signal samples with respect to a substantially predetermined level. In accordance with another embodiment, a method of detecting at the receiving end of a wireline communications system a frequency burst in a baseband signal transmitted via the wireline communications system comprises the steps of: filtering a component of a decoded signal derived from the baseband signal transmitted via the wireline communications system; and thresholding the filtered component.

Abstract: Briefly, in accordance with one embodiment of the invention, an oscillator frequency offset error estimator at the receiving end of a wireline communications system comprises: a phase comparator adapted to compare two successive signal samples, each signal sample being derived from a baseband signal transmitted via the wireline communications system. The phase comparator is further adapted to have at least one of the two signal samples provided along a signal path through a phase shifter and a time delay.

Abstract: Techniques for fault-tolerant computing which do not require fault-tolerant hardware or a fault-tolerant operating system. The techniques employ a monitor daemon which is implemented as one or more user processes and a fault-tolerant library which can be bound into application programs. A user process which is executing on ordinary hardware under an ordinary operating system is made fault tolerant by registering it with the monitor daemon. The degree of fault tolerance can be controlled by means of the fault-tolerant library. Included in the fault-tolerant library is a function which defines portions of a user process's memory as critical memory, a function which copies the critical memory to persistent storage, and a function which restores the critical memory from persistent storage. The monitor daemon monitors fault-tolerant processes, and when such a process hangs or crashes, the daemon restarts it.

Abstract: A protectively packaged connector for connecting multiple conductors is disclosed. The connector has multiple parts, each of which is provided with a protective covering of heat shrink thermoplastic film. The connector is assembled in the normal manner but with the film in place. This protects the connector from outside contaminants and is especially useful for filled connectors which readily attract contaminants because of the sticky waterproof filling compound.

Abstract: A method of joining a metal heat sink pallet to a circuit board by electroplating a layer of solder on the mounting surface of the pallet, placing and holding the circuit board metal circuit paths firmly against the plated mounting surface of the pallet and heating the pallet until the solder melts and alloys with the circuit paths. A nitrogen gas bath is used to inhibit oxidation during heating and alloying and a flux is used to promote alloying. A bonding fixture accurately positions the circuit board with respect to the pallet and applies pressure in circuit path areas of interest during heating, alloying and cooling to accurately position the circuit board on the pallet and to promote a superior mechanical and electrical bond between the circuit paths and the pallet.

Abstract: A method and apparatus for low bit rate coding of color video signals in which the use of the codebook entry identified by the codebook index may be bypassed in the coding of chrominance information when it is determined that it is advantageous to do so. In particular and in accordance with an illustrative embodiment of the present invention, the method comprises the steps of generating a codebook index signal based on the luminance information of the block being coded; determining a coding error based on a comparison of the chrominance information contained in the given block and the chrominance vector represented by the generated codebook index signal; and generating a chrominance vector bypass signal based on whether the coding error exceeds a threshold. Specifically, the chrominance vector bypass signal is used to indicate whether the chrominance information of the given block has or has not been coded with use of the codebook.

Abstract: DC offset cancellation and timing recovery is provided in a homodyne receiver. The homodyne receiver demodulates an RF signal to produce a baseband signal. An initial offset correction module determines an initial DC offset of the baseband signal. An initial offset correction is applied to the baseband signal to provide an initial corrected baseband signal. Wherein, a dynamic DC offset correction module determines a dynamic DC offset. A dynamic DC offset correction is applied to the initial corrected baseband signal providing a dynamic corrected baseband signal. A timing signal is acquired from the baseband signal for synchronizing the receiver to a transmitter. A method for correcting DC offset of a baseband signal in a homodyne receiver is also described.

Abstract: A signal processor with an embedded Viterbi co-processor which works in parallel with the signal processor is disclosed.

Abstract: A novel and advantageous cathode structure for a field emission display apparatus is disclosed. A given pixel comprises a multiplicity of spaced apart emitter bodies on a support. A given emitter body comprises diamond and/or rare earth boride, and has a relatively sharp geometrical feature that facilitates electron emission from the emitter body. By way of example, the emitter body comprises diamond bodies grown on a support, or it comprises a pre-existing diamond particle that was placed on the support. Such emitter bodies generally can be provided easily and at low cost, and typically have naturally occurring sharp geometrical features such as points and edges. We have also discovered that appropriately grown rare earth boride films of thickness 30 nm or less may substantially improve electron emission from emitter bodies, and some preferred embodiments of the invention comprise a cathode structure that comprises a thin layer of, e.g., LaB.sub.6 on the emitter bodies.

Abstract: Four cameras provide a 360 degree view of an area using a four sided pyramid shaped element. The four sides of the pyramid shaped element are reflective and reflect images from four different directions. Each camera is positioned to receive a reflected image from one of the reflective sides of the pyramids. The cameras are arranged so that they share a common virtual optical center.

Abstract: A system and method are disclosed for detecting an event-related signal among noise, where the system includes memory for storing measurement values and may include a processor for generating residual values associated with the measurement values, and for detecting the event-related signal using the residual values.

Abstract: The device has a single strip having a first end, a second end, a length and a width. The first end of the strip is curved toward the second end of the strip to form a loop having a height. The length is approximately 10 mm, the width is approximately 5-8 mm, and the height is approximately 0.8-1.2 mm. The loop is preferably fabricated from copper. The loop is mounted directly to a test instrument such as a computer controlled impedance analyzer or network analyzer. The test instrument measures the inductance and resistance of the loop with no thin film sample placed therein, and then measures the inductance and resistance of the loop containing the sample under test. From these measurements, the device ultimately derives the permeability of the sample under test.

Abstract: A correlation feedback method and apparatus for multi-channel stabilization of a multi-channel transmitter in which a single external receiver is used to detect the total power output from the multi-channel transmitter and to control each channel by correlating the total power output signal with channel data to measure the channels' signal power and control the output power via a feedback loop. The inventive system is suitable for use with and able to accommodate both integrated lasers and an array of discrete independent lasers; the system is also equally applicable for use with channels comprising random independent data or broadcast data.