Abstract: In some wireless local area networks (WLANs), signals of different modulation types and rates can be received. To operate optimally, the gain of an amplifier in a receiver can be set based on a specific modulation type and rate. For example, the gain of a receive path amplifier can be changed based on one or more unique identifying characteristics in a received data packet. Once the unique identifying characteristics are located, they can be analyzed to determine which modulation type and rate are represented. The appropriate gain of the amplifier can be set based on the modulation type and rate. Advantageously, subsequent data symbols can be amplified with the set gain, thereby ensuring that the receiver optimally receives those data symbols.

Abstract: A Viterbi decoding system interprets bits in received QAM constellations as many-valued parameters rather than binary valued parameters. It performs the Viterbi algorithm using these many-valued parameters to provide results superior to hard decision decoding. Rather than applying a hard 0-1 function to the QAM data, the system uses a non-stepped linear or curved transfer function to assign values to the bits. In another aspect, a system differentiates between data bits based on their estimated reliability, giving more emphasis to decoding reliable bits than unreliable bits using any of a variety of techniques. By differentiating between good and bad bits and de-emphasizing or ignoring unreliable bits, the system can provide a significant reduction in uncorrectable errors and packet loss.

Abstract: A dual band radio is constructed using a primary and secondary transceiver. The primary transceiver is a complete radio that is operational in a stand alone configuration. The secondary transceiver is a not a complete radio and is configured to re-use components such as fine gain control and fine frequency stepping of the primary transceiver to produce operational frequencies of the secondary transceiver. The primary transceiver acts like an intermediate frequency device for the secondary transceiver. Switches are utilized to divert signals to/from the primary transceiver from/to the secondary transceiver. The switches are also configured to act as gain control devices. Antennas are selected using either wideband or narrowband antenna switches that are configured as a diode bridge having high impedance at operational frequencies on control lines that bias the diodes.

Abstract: A radio communication device is tested by forwarding relevant signal characteristic data derived at the physical (PHY) layer to the media access control (MAC) layer for processing, analysis and feedback to the radio circuit to improve performance. The relevant signal characteristics are forwarded to the MAC within (appended to) a data packet. Thus, the relevant signal characteristic is forwarded to the MAC along an existing data path (a path originally designed to transfer the receive frame only, but now transfers the combined receive frame with the attached radio characteristic). The radio characteristic may be used for testing and/or tuning the radio circuit. In one embodiment, the radio characteristic is a frequency domain representation of a received signal. The radio is tuned based on a channel estimate derived from comparison of frequency domain representations of transmitted and received signals.

Abstract: A Viterbi decoding system interprets bits in received QAM constellations as many-valued parameters rather than binary valued parameters. It performs the Viterbi algorithm using these many-valued parameters to provide results superior to hard decision decoding. Rather than applying a hard 0-1 function to the QAM data, the system uses a non-stepped linear or curved transfer function to assign values to the bits. In another aspect, a system differentiates between data bits based on their estimated reliability, giving more emphasis to decoding reliable bits than unreliable bits using any of a variety of techniques. By differentiating between god and bad bits and de-emphasizing or ignoring unreliable bits, the system can provide a significant reduction in uncorrectable errors and packet loss.

Abstract: A Viterbi decoding system interprets bits in received QAM constellations as many-valued parameters rather than binary valued parameters. It performs the Viterbi algorithm using these many-valued parameters to provide results superior to hard decision decoding. Rather than applying a hard 0-1 function to the QAM data, the system uses a non-stepped linear or curved transfer function to assign values to the bits. In another aspect, a system differentiates between data bits based on their estimated reliability, giving more emphasis to decoding reliable bits than unreliable bits using any of a variety of techniques. By differentiating between god and bad bits and de-emphasizing or ignoring unreliable bits, the system can provide a significant reduction in uncorrectable errors and packet loss.

Abstract: A radio communication device is tested by forwarding relevant signal characteristic data derived at the physical (PHY) layer to the media access control (MAC) layer for processing, analysis and feedback to the radio circuit to improve performance. The relevant signal characteristics are forwarded to the MAC within (appended to) a data packet. Thus, the relevant signal characteristic is forwarded to the MAC along an existing data path (a path originally designed to transfer the receive frame only, but now transfers the combined receive frame with the attached radio characteristic). The radio characteristic may be used for testing and/or tuning the radio circuit. In one embodiment, the radio characteristic is a frequency domain representation of a received signal. The radio is tuned based on a channel estimate derived from comparison of frequency domain representations of transmitted and received signals.

Abstract: Specific bits of an incoming transmission are compared against a predetermined bit pattern. If the selected bits do not match the predetermined bit pattern, then the incoming transmission is rejected as a false packet. The predetermined bit pattern can include legal values for predetermined bits in a plurality of fields. Notably, these legal values are set by a networking standard. A parity check may check may be performed in addition to checking for predetermined bits in other fields. A user interface can be used to determine the predetermined bit pattern.

Abstract: A Viterbi decoding system interprets bits in received QAM constellations as many-valued parameters rather than binary valued parameters. It performs the Viterbi algorithm using these many-valued parameters to provide results superior to hard decision decoding. Rather than applying a hard 0-1 function to the QAM data, the system uses a non-stepped linear or curved transfer function to assign values to the bits. In another aspect, a system differentiates between data bits based on their estimated reliability, giving more emphasis to decoding reliable bits than unreliable bits using any of a variety of techniques. By differentiating between god and bad bits and de-emphasizing or ignoring unreliable bits, the system can provide a significant reduction in uncorrectable errors and packet loss.

Abstract: A method and system is presented for a digital licensing scheme that separates the license from the digital file containing the copyrightable material. According to the present invention, the files can be downloaded from any server, and transferred from user to user, even after the file has been licensed. The present invention utilizes producer software running on a vendor's computer, server software running on a computer provided by the license provider, and player software operating on the user's computer. Digitally encrypted communication streams keep communications between the producer software, the license provider, and the player software confidential. A software component running on the user's computer checks to make sure that the appropriate product license has been purchased. This is accomplished by comparing the product ID in the product license with the product ID contained in the product file.

Abstract: The present invention provides a method of and an apparatus for changing the gain of a receive path amplifier during the middle of a packet transmission, and particularly changing the gain during a guard interval between a symbol with encoding bits disposed therein and a subsequent data symbol encoded in a manner corresponding to the encoding bits.

Abstract: A circuit for texture tag checking includes a first comparison gate which compares a first dimension field of a tag with a first dimension element for a group of texels associated with a sample point. A second comparison gate compares a second dimension field of the tag with a second dimension element for the group of texels. A logic gate, coupled to each of the first and second comparison gates, is associated with one texel of the group of texels. The logic gate outputs a predetermined signal if the first and second dimension fields of the tag are the same as the first and second dimension elements, respectively.

Abstract: A Viterbi decoding system interprets bits in received QAM constellations as many-valued parameters rather than binary valued parameters. It performs the Viterbi algorithm using these many-valued parameters to provide results superior to hard decision decoding. Rather than applying a hard 0-1 function to the QAM data, the system uses a non-stepped linear or curved transfer function to assign values to the bits. This results in performance superior to pure hard decision decoding and approaches that of soft decision decoding; moreover, it is applicable in many situations where soft decision decoding cannot be used.

Abstract: A graphics processing system includes an initial processing system that receives a command to render an image component polygon and generates parameters for calculating image values for the image component polygon. The graphics processing system also includes a backtrack register capable of storing a pixel location. A rasterization engine scans a pixel span in a selected direction and determines whether the pixel span is to be scanned in a direction opposite the selected direction. The rasterization engine stores a backtrack location in the backtrack register in response to a determination that the pixel span is to be scanned in a direction opposite the selected direction, and stores a location to begin scanning a subsequent pixel span in the backtrack register in response to a determination that a backtrack location is not stored in the backtrack register. The rasterization engine also calculates image values for each pixel in the pixel span in the current scan direction.

Abstract: The present invention provides a method of and an apparatus for changing the gain of a receive path amplifier during the middle of a packet transmission, and particularly changing the gain during a guard interval between a symbol with encoding bits disposed therein and a subsequent data symbol encoded in a manner corresponding to the encoding bits.

Abstract: A method and system is presented for a digital licensing scheme that separates the license from the digital file containing the copyrightable material. According to the present invention, the files can be downloaded from any server, and transferred from user to user, even after the file has been licensed. The present invention utilizes producer software running on a vendor's computer, server software running on a computer provided by the license provider, and player software operating on the user's computer. Digitally encrypted communication streams keep communications between the producer software, the license provider, and the player software confidential. A software component running on the user's computer checks to make sure that the appropriate product license has been purchased. This is accomplished by comparing the product ID in the product license with the product ID contained in the product file.

Abstract: A method and system is presented for storing multiple tracks of music in a single structured storage file having multiple layers of organization. The top layer contains links to separate “folders” for each track, as well information associated with the collection of tracks as a whole. Inside each track folder is the digital data defining the music track, as well as information concerning that track. Audio/video information associated with the collection can be stored in the root file, while audio/video information associated with the track is stored in the track folder. A file header in the root directory contains a vendor ID and a product ID, which allows licensing software to examine the file and uniquely associate it with a particular license. Preview tracks contained in the track folders can be played if the no license exists. To prevent tampering with the product or vendor ID, the header file is encrypted with DES encryption using an encryption key common to all files.