Abstract: The present invention relates to a circuit for protecting inputs and outputs on semiconductor devices. The protective circuit is particularly useful on high-speed inputs or outputs (such as in radio frequency applications where signal frequency is on the order of 100 MHz or greater and where it is necessary to minimize capacitive loading. Briefly, the present invention utilizes two FETs to shunt harmful electrostatic charges to a low impedance power bus and protect input and output circuit elements from damage or degradation. When a high voltage transient surge is detected, the drain-gate capacitance of one of the FETs couples the voltage to the gate electrode and biases one of the two transistors in the low impedance state so that the surge is absorbed without damage to the input or output circuit. Significantly, the capacitive loading of the protection circuit of the present invention is typically a fraction of a picoFarad and more particularly on the order of several hundred femtofarads.

Abstract: A variable sample rate converter, adaptable to rational ratios, converts a plurality of data having a first sample rate to a plurality of data having a second sample rate. The variable sample rate converter is employed in data processing devices including, for example, color photo-copy machines, color facsimiles, color printers, black and white printers, digital cameras, and digital printers. A finite impulse response filter is employed to perform processing of the plurality of data. Any processing hardware capable of performing floating point processing may employ the variable sample rate converter. A ping-pong style buffer is employed to assist in transferring the plurality of data. The variable sample rate converter combines the two steps of up-sampling and down-sampling into a single step, thereby maximizing available processing resources.

Abstract: A technique of allocating data cells by a segmentation and reassembly (SAR) controller for transmission on a network connection such as an asynchronous transfer mode (ATM) network connection provides a scaleable sustainable cell rate (SCR) when the sum of the SCRs of virtual circuit exceeds the connection bandwidth. In addition, bandwidth can be shifted from a VC which is using less than its allocated SCR to a VC that is exceeding its SCR. In addition, the method enables a VC to exceed it peak cell rate (PCR) to some extent. The method and system of the disclosed embodiment can also be employed to dynamically adjust SCRs and PCRs in a variable bandwidth channel and is programmable and thus more flexible and less expensive than possible hardware solutions.

Abstract: A method for fabrication of ceramic tantalum nitride and improved structures based thereon is disclosed. According to the disclosed method, an ionized metal plasma (“IMP”) tool is used to create a plasma containing tantalum ions where the plasma is sustained by a mixture of nitrogen and argon gases. The percentage of nitrogen partial flow in the mixture of gases is adjusted so as to result in a layer of tantalum nitride with a nitrogen content of at least 30%. With a nitrogen content of at least 30%, the tantalum nitride becomes ceramic. The ceramic tantalum nitride presents a number of advantages. For example, the fabrication of ceramic tantalum nitride can be easily incorporated into fabrication of semiconductor chips using copper as the interconnect metal. Also, ceramic tantalum nitride can be used as an effective etch stop layer.

Abstract: An improved dielectric material having pores formed therein and a method for forming the material are disclosed. The material is formed of a polymer. Pores within the polymer are formed by forming solid organic particles within the polymer and eventually vaporizing the particles to form pores within the polymer.

Abstract: A differential LC-based voltage-controlled oscillator (LC-VCO), charge pump and loop filter architecture for providing improved noise immunity in integrated phase-locked loops (PLLs). A pair of voltage control signals are provided from a differential charge pump and loop filter architecture to respective voltage control inputs in the LC-VCO to differentially control the LC-VCO. The voltage control inputs are connected to respective terminals on opposite ends of a varactor tuning circuit. The differential voltage applied across the varactor tuning circuit determines the LC characteristics of the varactor tuning circuit which, in turn, determines the operating frequency of the VCO. One of the voltage control inputs is passed through an operational amplifier buffering stage before being transmitted to its respective terminal in the varactor tuning circuit. The LC-VCO utilizes a PMOS transistor core to provide good substrate isolation and low flicker (1/f) noise.

Abstract: A system and method for providing soft modem and soft audio copy protection for hardware interfaces and software code utilized in an AC '97 architecture to prevent against unauthorized copying. The system confirms that a codec connected to the AC '97 architecture is provided by a desired supplier. The system performs a sample rate negotiation to determine an operating sample rate for data transfer. When the system provides a desired sample rate which does not correspond to a sample rate appearing in a predefined set of sample rates supported by an AC '97 architecture, the system expects the codec to echo back a predesignated sample rate during the sample rate negotiation indicating that a desired sample rate has been received which does not correspond to one of the supported sample rates. When the system determines that the predesignated sample rate has been echoed back, the copy protection system recognizes the codec as being provided by an authorized supplier and authorizes the codec for operation.

Abstract: Silence description coding for multi-rate speech coding systems that employ discontinued transmission. Speech coding systems include multi-rate speech codecs having an encoder and a decoder. The silence description coding is performed in either the encoder or the decoder of the multi-rate speech codec. It may also be performed in a distributed manner wherein it is performed partially in the encoder and partially in the decoder. The silence description coding is performed on a speech signal having a substantially non-speech-like characteristic. Voice activity detection classifies the speech signal as being either substantially speech-like or substantially non-speech-like. The silence description coding is selected from a plurality of coding modes. In certain embodiments of the invention, the silence description coding is a source coding mode that operates at a bit rate that fits within a bit rate budget as determined by all of the available source coding modes within the plurality of coding modes.

Abstract: An audio codec having an encoder and a decoder is disclosed. The encoder enables the compression of an audio signal for transmission or storage while the decoder receives a compressed audio signal for playback. A time scaling module within the decoder allows variation of the playback rate of the compressed audio signal. Further, no significant depreciation in the quality of pitch occurs as a result of varying the playback rate. The codec features a control for independently varying the playback rate and a module for delivering pitch compensation. The encoder utilizes a sub-band coding scheme (e.g., MPEG-1 and MPEG-2) wherein an audio signal is split into at least two frequency sub-bands for compression. Using a filter bank having two filters, for example, the audio signal is split into the frequency sub-bands. An decoder having a time scaling module is further disclosed. The time scaling module time stretches or compresses an audio signal as desired using a synchronized overlap and add (SOLA) algorithm.

Abstract: A method and apparatus for controlling and shaping the spectrum of transmitted signal samples having predetermined frequency characteristics and allowable transmit signal levels. A running measure of unwanted components is measured and, for each block of the transmitted samples, an objective function based on the previously calculated running measure is computed. Depending upon the measurements, redundancy is determined and selected for each block of the transmitted samples. Accordingly, at least one redundant sample may be added or, the sign of the sample modified, at structured or randomized locations within the block to optimize the objective function.

Abstract: Apparatus and methods are provided for encoding video data in a manner which significantly reduces the computation performed by the video encoder and the video decoder without suffering any degradation in the perceived quality of the compressed video data. In particular, apparatus and methods are provided for determining which blocks might be zeroed out after quantization. This determination is performed after motion estimation, the classification of the frame as either an I frame, P frame, or a B frame, and the determination of a quantization step size (QP) for the block, but before DCT. If a given block is determined to be a “zero” quantized block, then the DCT, quantization, zig-zag scan and variable length coding steps are omitted, and a variable length code output is provided indicating that the block B is a “zero” quantized block.

Abstract: A substrate based package design for semiconductor chips is disclosed which reduces ground loop inductance. The design includes a substrate having a metal layer providing electrical interconnections. The metal layer includes a first conductive area adapted to provide an electrical ground, and a second conductive area adapted to provide an electrical connection to a power supply voltage. The first conductive area has a plurality of first conductive finger extensions providing electrical connections to vias for the electrical ground, and the second conductive area has a plurality of second conductive finger extensions providing electrical connections to vias for the power supply voltage. The first finger extensions and the second finger extensions are interlaced with each other. In accordance with another aspect of the invention, an internal conductive ring for ground is provided, with a concentric outer conductive ring for power supply connections.

Abstract: Disclosed is an apparatus for modifying a radio frequency signal. In one embodiment, the apparatus includes a mixer, an amplifier module and an interface circuit. The mixer is configured to receive a first signal having a first frequency and a second signal having a second frequency, and to output a third signal which is a function of the first and second signals. The amplifier module includes a first amplifier stage and a second amplifier stage and is configured to amplify a communications signal which is then input into the mixer as the first signal. The first and second amplifier stages are in communication via a first signal path and a second signal path. The interface circuit is interposed between the mixer and the amplifier module, and inserted into the second signal path so that a DC bias current flows from the first amplifier stage through the interface module into the second amplifier stage.

Abstract: A method and apparatus 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 communications system. A predetermined set of parameters is extracted from the incoming speech signal, including a pitch gain and a pitch lag. A frame voicing decision is made for each frame of the incoming speech signal according to values calculated from the extracted parameters. The predetermined set of parameters further includes a partial residual frame full band energy, and a set of spectral parameters called Line Spectral Frequencies (LSF). A signal-to-noise value is estimated and tracked to adaptively set threshold values, thereby improving performance under various noise conditions.

Abstract: An amplifier circuit including a novel degeneration input stage that permits a low Noise Figure and superior linearity to be achieved in combination. The amplifier is suitable for use in fully integrated direct-conversion tuner circuits, and provides continuously variable gain functionality implemented by steering current away from an output load of the amplifier through differential transistor pairs located in the current signal paths of an input stage. Voltage headroom problems are avoided by placing the attenuation resistors of the degenerated input stage in the signal path, such that there is little or no DC voltage drop across the resistors. Further, this arrangement permits very accurate on-chip matching to an off-chip signal source. The distribution of IP3 values over the gain range of the amplifier, as well as gain and NF characteristics, are dependent on resistor ratios rather than absolute values. These amplifier characteristics are thus largely temperature and process independent.

Abstract: An imager reduces lighting induced flicker by setting its pixel integration time to an integral multiple of the periods between peak intensity of the lighting. In one implementation, flicker is reduced in a 30 Hz frame rate camera capturing an image lighted with 50 Hz lighting by setting the integration time to approximately 10 ms, the period between lighting intensity peaks.

Abstract: A cable modem provides upstream data signals in a cable system on a return channel. The upstream data signals are provided in a 50-550 MHz frequency range and yet do not affect the picture quality associated with conventional cable television signals. The data is provided on vestigial sidebands associated with the cable television signals or during black periods associated with the cable television signals. The data can be modulated in accordance with quadrature amplitude modulation (QAM) techniques.

Abstract: A modem system start-up routine is performed in an improved manner such that information related to the exchange of the operational capabilities of the modem devices is transmitted at a higher data rate than prior art systems. A transition protocol is utilized to enable the modem system to seamlessly shift operating modes during the start-up routine. An initial data rate is utilized to transmit initial capabilities exchange data near the beginning of the start-up routine. Next, an initial training procedure is conducted to train the receive modem for operation at an intermediate data rate. The exchange of operational capabilities occurs at this intermediate data rate. Eventually, the modem system shifts to the primary data rate utilized during the normal data transmission mode. A final training procedure is performed to tune the receive modem in a more precise manner in response to the primary data rate. The overall effect of the improved start-up routine is a reduction in the start-up latency time.

Abstract: Method for dual damascene metallization of semiconductor workpieces which uses a process for creating an etch stop in an insulator thereby eliminating the need for deposition of an etch stop layer. Electron beam exposure is used to cure the insulator, or material having a low dielectric constant. Application of the electron beam to the low dielectric constant material converts the topmost layer of the low dielectric constant material to an etch stop layer, while rapid thermal heating cures the remainder of the low dielectric constant material. Creation of an etch stop layer in the low dielectric constant material can also be achieved by curing the low dielectric constant material using ion implantation.

Abstract: A compression system and process employs a group of quantizers (or sets of predefined quantized values) and involes the selection of the quantizers for each video frame or frame portion. For each frame portion, a selection of the most appropriate quantizer is made. The selection of which quantizer from the selection group is most appropriate for coding of a video frame or frame portion is based on a formula which takes into account both the distortion (accuracy) and bit rate characteristics of each quantizer. The quantizer that exhibits the best combined distortion and bit rate characteristics is selected for coding the frame or frame portion. A similar formula, based on both distortion and bit rate characteristics, is used to select the particular quantization value within the quantizer set for each video signal value being coded.