Abstract: A method and telecommunication system for tracking the carrier phase of a received signal includes the addition of a pilot signal to the data component of the signal prior to modulation and transmission. The pilot signal is specified to have a frequency equal to the inverse of twice a data symbol interval with zero crossings positioned at the midpoint of each symbol interval to avoid interference with the data. The received signal is demodulated to produce a complex data signal from which the pilot signal is detected to provide an estimate of the phase error in the complex data signal. The elimination of the phase error from the complex data signal is accomplished through a corrective phase shift that is equal and opposite to the estimated phase error. A sample timing estimate may also be obtained in a similar manner.

Abstract: The output of an analog modem (12) at a remote cellular station (14) is converted to a digital signal in accordance with G.711 compaction before being applied to a processing chain (36) that results in wireless transmission to a cellular-telephone base station (24). Together with a signal chain (50) at the base station, the remote station's processing chain forms a transparent channel whose output is applied directly to a digital land-line span of the public switched telephone network. Because the G.711 encoding is the same as that conventionally employed for voice communication over a PSTN digital span, the modem's performance is the same in the absence of link errors as that which would result from conventional coupling directly to a PSTN digital link.

Abstract: A computer system and computer implemented method for deriving constraints with which to direct automatic integrated circuit layout is disclosed. The present invention is particularly adapted for use in the design of large integrated circuits with complex synchronous timing behavior. Preferably, the invented computer system includes means for storing a netlist data structure within a storage means is provided, the netlist data structure representing a circuit configuration having a plurality of circuit elements and representing static timing information for the circuit configuration; means for selecting specified circuit elements to be used for generating the layout constraints, whereby the specified circuit elements that are selected are fewer than, i.e.

Abstract: A receiver (10) for extracting complex values by reference to a local frequency reference determines the frequency offset between a local oscillator (16) and the carrier by employing a circuit (40) for determining a "phase rotation." When a record of the input signal is determined to have resulted from a predetermined reference sequence of complex values, the phase-rotation circuit (40) compares the phases of complex values extracted from this record with corresponding symbols of the reference sequence. By comparing this difference for one part of the sequence with that for another, circuitry (38, 50, 52, 53, 54) in the receiver infers the frequency offset between the transmitter reference and the receiver reference, and a complex multiplier (34) compensates for this offset by multiplying the successive complex-valued samples by a complex exponential whose frequency is the negative of the frequency offset.

Abstract: An energy efficient process for hydrolyzing lignocellulosic materials which comprises using a primary system by providing a start-up energy input to operating saturated steam conditions and thereafter operating the primary system with substantially constant energy input, the condition of the hydrolysing saturated steam being controlled by water injection and/or steam bleeding from the primary system. The dwell time of the solids stream in the primary system is controlled by controlling its passage with flashing off of steam into a secondary system where drying occurs together with some small measure of hydrolysis in a lower pressure superheated steam environment, there being an energy input into the secondary system using steam bled from the primary system. The output solids material stream is preferably capable of being self polymerized into a formed shape eg a board.

Abstract: A technique for correcting the sampling time and carrier frequency error in a receiver for digitally modulated signals. Discrete-time, complex-valued samples of the incoming signal are fed to a pair of non-linear operators such as correlators. The first correlator provides a signal having a first phase component related to the symbol timing error and a second phase component related to the carrier frequency error. The second correlator provides a signal having a first phase component related to the symbol timing error and a second phase component related to the negative of the carrier frequency error. The phase components are then separated and detected to extract an estimate of the symbol timing error and the carrier frequency error. In the preferred embodiment, the complex-valued samples are frequency-shifted, before being fed to the correlators, so that the phase components of interest appear at zero frequency.

Abstract: A simulation system for circuit design is disclosed. The system couples a schematic editor and simulator to allow incremental changes to a design under test without requiring prior shutdown of the simulator. The system uses a method which permits a wide range of changes to the design and provides a resulting netlist for the changed design. Changes can be made to the schematic which include changes in hierarchy, addition or deletion of components (including hierarchical components), addition or deletion of signals at any level within the design hierarchy, addition or deletion of interconnections of components at any level of hierarchy within the design, addition and deletion of interface ports for any component type, substitution of a new component for an existing one (including swapping hierarchical and behavioral descriptions), and alteration of parametric data such as device delay timing. The simulation continues to run after design changes are made.

Abstract: A method of making a closed-tread staircase, and of making steps for such a staircase. The tread and riser of each step are each made from a rebated, grooved slab; the rebates on tread and riser are mated to form a joint, which is secured by a joining strip of `V`-shaped cross-section formed with flanges which are forced into the slab grooves. Steps are joined together in the same manner, and a staircase formed by supporting a series of steps upon two or more stair carriages, each carriage comprising a stringer with a series of spaced cleats secured to one side. Each cleat provides a horizontal tread-supporting portion and a vertical riser-supporting portion. Each stair carriage may be made using apparatus which provides means for supporting and indexing a stringer and supporting each cleat at a predetermined angle while cleat and stringer are secured together.