Abstract: An apparatus and method of quantizing a sequence of input data vectors using delayed decision switched prediction and vector quantization. The method has the following steps of operation: (a) predicting a next vector element from said sequence of input data vectors to generate a set of prediction vectors; (b) subtracting the set of prediction vectors from the next vector element to generate a set of prediction error vectors; (c) multi-stage vector quantizing the set of prediction error vectors to generate a set of quantized prediction error vectors with each of the stages having at least one of the tables and local decision means to generate a final quantization error vector according to a predetermined distance measure; (d) selecting one predictor out of the set of predictors from the switched prediction step and selecting, for each of the stages, at least one entry from the set of tables of the vector quantization step according to the predetermined distance measure, generating a quantized data vector.

Abstract: A method is disclosed for generating frame voicing decisions for an incoming speech signal having periods of active voice and non-active voice for a speech encoder in a speech communication system. The method first extracts a predetermined set of parameters from the incoming speech signal for each frame and then makes a frame voicing decision of the incoming speech signal for each frame according to a set of difference measures extracted from the predetermined set of parameters. The predetermined set of extracted parameters comprises a description of the spectrum of the incoming speech signal based on line spectral frequencies ("LSF"). Additional parameters may include full band energy, low band energy and zero crossing rate.

Abstract: A method of digital data transmission between a first transceiver and a second transceiver is disclosed. The first transceiver has a first transmitter and a first receiver and the second transceiver has a second transmitter and a second receiver. The first transmitter also contains a programmable encoder for encoding its transmission, while the second receiver uses at least one of a plurality of error correcting codes (ECC's) for decoding its reception. Each ECC can be specified by a predetermined set of parameters.

Abstract: A testing and evaluation system for efficiently qualifying individual components of a modem. A modem data pump acts as a dBm meter by measuring distortion, noise floor, and echo. The modem is coupled to a computer and a remote modem. After calibration, the remote modem may be disconnected. A resistor having a preselected resistance is coupled to the modem to allow the computer to measure the modem noise floor and distortion independent of particular telephone connections. An echo canceler coupled to the receive line allows the sum distortion and noise to be measured.

Abstract: A cordless telephone system connectable to the public switched telephone network having a base station and one or more handsets communicating with the base station by an RF link utility time division duplex direct sequence spread spectrum modulation technique, having a digital variable rate automatic gain control loop. The gain is varied by changing the scale factor for the discriminator output. A high gain scale factor is used during signal acquisition. When the signal has been acquired, a low scale factor is utilized during signal tracking. The controller in the base station and in the handset causes gain use of the different scale factor at the appropriate time.

Abstract: A method and apparatus for iterative carrier frequency estimation of a base station by a mobile station in a wireless communication system is disclosed. Upon detecting a frequency correction burst ("FCB") signal from the wireless transmission of the base station, the mobile station first buffers the FCB signal and then filters the buffered signal with a bandpass filter to generate a first set of filtered data. After filtering, the first filtered data is again filtered with an auto-regressive filter to generate a corresponding set of second filtered data. With the second filtered data, iterative pole estimation of the AR filter and filtering by the AR filter is made for a predetermined set of iterations to generate a converged pole estimate, which can then be used to derive the carrier frequency of the base station.

Abstract: A automatic skywave communications system includes a control channel and one or more traffic channels for voice or data communications. The system automatically establishes and maintains traffic radio links. The system measures, reacts, signals and adapts system parameters.

Abstract: A method for testing a communication link between first and second components of a system, which components communicate via a selected one of a plurality of broadcast channels, the second component being powered by a self-contained power source, the method comprising: causing the first component to scan a plurality of the broadcast channels in sequence in a receiving mode during a scanning period and to broadcast a test signal over the selected channel during the scan; and maintaining the second component in an inactive state in which energy consumption is minimized and in which the second component is unresponsive to broadcast signals during a major part of the scanning period, placing the second component in an active state in which the second component can detect the test signal during a time when the test signal is being broadcast, and causing the second component to broadcast a response signal upon detection of the test signal.

Abstract: A circuit for reducing switching noise caused by harmonics of an output coupled to a band of interest in a mixed signal communication device, with the mixed signal communication device having a predetermined sampling clock.

Abstract: A method is provided for normalizing correlation data from a holographic correlator. After a sequence of object image patterns are recorded in an angularly multiplexed hologram, the entire volume hologram contents are read out with a uniform (plane wave) object beam. The plane wave readout produces an array of spots at a correlation plane, with the intensity of each spot representing the strength of the recorded hologram for the corresponding stored image pattern. The spot intensity values are accurately detected and stored as normalization factors. Holographic correlation output array values produced by parallel comparison of an input object pattern with the stored image patterns are then divided by the corresponding normalization factors. The resulting normalized correlation output accurately represents the true degree of correlation between the input object pattern and the stored image patterns by eliminating the uncertainty factor.

Abstract: A system and apparatus for enhancing the satellite based navigation systems which includes providing an aircraft with an interrogating radar for interrogating beacons disposed at a predetermined location in front of a runway wherein the beacons are radar-activated passively powered runway beacons.

Abstract: A method of free form fabrication of metallic components, typically using computer aided design data, comprises selective laser binding and transient liquid sintering of blended powders. The powder blend includes a base metal alloy, a lower melting temperature alloy, and a polymer binder that constitutes approximately 5-15% of the total blend. A preform part is built up, layer-by-layer, by localized laser melting of the polymer constituent, which rapidly resolidifies to bind the metal particles. The binder is eliminated from the preform part by heating in a vacuum furnace at low atmospheric pressure. The preform part may require support during elimination of the polymer binder and subsequent densification by controlled heat treatment. Densification is performed at a temperature above the melting point of the lower temperature alloy but below the melting point of the base metal alloy to produce transient liquid sintering of the part to near full density with desired shape and dimensional tolerances.

Abstract: An subsystem processor for converting an input audio signal to complex audio samples for QADM processing by a modem for communication with a remote modem is disclosed. The audio process comprises a decorrelator for processing the input audio to generate a residual signal, an adaptive scaler for adaptively scaling the residual signal to generate a scaled residual signal, a randomizer for phase-randomizing the scaled residual signal to generate a complex signal with randomized phases, and a limiter for limiting the complex signal with randomized phases, such that the complex signal is transmitted by the modem to a remote modem.

Abstract: A system for processing signals by utilizing a tracking loop that contains two or more detectors that operate simultaneously in order to detect a frequency shift in the locally generated reference signal. A correction can then be transmitted to the tracking loop filter to minimize the effect of the detected frequency shift. In this manner lock can be maintained without the expenditures associated with the use of temperature controlled or compensated oscillators.

Abstract: The present invention involves enhancing machine-readable matrix symbol markings on substrate materials by the addition of magnetizable materials, and then, at a later time, taking advantage of the magnetic properties associated with the matrix symbol marking to read the marking using a magneto-optic reading apparatus. For example, the marking material may be mixed with a media having magnetic properties and applied to a component surface either via stencil or as backfill. The magnetic material enables detection with the aid of a magnetic-property detection apparatus. Once detected, the matrix symbol image is transmitted to a symbol decoder so that the information represented by the symbol can be provided to a user.

Abstract: An apparatus 200 and method for detecting when an interruption occurs between an agent associated with a telephonic switch, such as an automatic call distributor 100, and a caller during an incoming telephone call. The automatic call distributor 100 routes incoming telephone calls generated by callers at external telephonic units 102 to agents located at agent telephonic units 106. Additional information concerning incoming telephone calls is displayed to the agents on agent terminals 118. The apparatus 200 includes a detection circuit 210 for detecting when an agent and a caller are concomitantly talking during an incoming telephone call. A caller audio signal detector 216 detects caller audio signals representative of the speech of a caller on a first bus 204 in the automatic call distributor 100. Similarly, an agent audio signal detector 222 detects agent audio signals representative of the speech of an agent on a second bus 208 in the automatic call distributor 100.

Abstract: A low voltage driver tolerant of high voltage and suitable for driving a processor and a memory device. A first protection NFET is coupled to the drains of a series-coupled PFET and NFET forming the basic driver components. Another protection NFET is connected in series to the first NFET. This second protection NFET requires approximately 1 volt for turn on, such that a resultant 3 volts appear at the output of the complete driver assembly. When the output driver is not enabled and 5 volt inputs are being applied from the memory circuit, the two NFET protection transistors block the 5 volts from reaching the processor output driver.

Abstract: A device and a method of manufacture for the device, in which the device is a metallic canister having a detachable lid that is fastened onto the canister having an indium-tin intermetallic gasket disposed between the lid and the edge of the canister adjacent to the lid. Heating the entire apparatus at a predetermined temperature less than the melting point of indium-tin intermetallic for a specified time period such that the indium and a tin coating on the lid and canister surface interact to form an intermetallic compound that provides a seal which will satisfy operating requirements for being, designated a hermetic seal. The condition of the seal improves over time, due to the continued interaction between the tin and indium alloy.

Abstract: A frequency error calibration, estimation and compensation device and method for direct sequence spread spectrum systems, such as digital cordless telephones having a handset and a base station. Initial frequency calibration occurs when the handset is physically coupled to the base station. The allowable frequency error range is divided into a plurality of frequency bins. Both the handset and base station transmit and receive messages using a predetermined frequency offset bin as an estimate of the frequency error. A signal quality value is determined and then a next bin is selected and a next signal quality value is determined. Once a signal quality value has been determined for each frequency bin, a communications link is established between the handset and the base station to allow automatic frequency control tracking to fine tune the frequency offset value. If the signal quality is not above a threshold value, the procedure is repeated.

Abstract: An optical device for transforming light and an associated liquid crystal display is disclosed. The device includes a layer of cholesteric material of the type which transmits light having a first circular helicity and reflects light having a second circular helicity. A quarter-wave plate positioned on a first side of the layer of cholesteric material converts the transmitted light having the first circular helicity into linearly polarized light. A compensator including a positively birefringent C-plate layer is disposed between the layer of cholesteric material and the quarter-wave plate. The compensator reduces undesirable phase effects in the transmitted light introduced by the layer of cholesteric material. The disclosed LCD employs the optical device to increase backlighting efficiency while improving field of view and chromaticity of the display.