375results about "Optical analogue/digital converters" patented technology

A ultra high speed photonic Analog to Digital Converted (ADC) for sampling and quantizing an electrical voltage signal, internally enabled by photonics uses coherent optical detection architectures for photonic quantization. Coherent light is phase modulated by the test signal. Using an interferometer, or an array of interferometers the phase of modulated light is compared with a reference light. Flash ADC, successive approximation ADC and delta-sigma ADC configurations are presented.

Microstructures are fabricated by impinging a radiation beam, such as a laser beam, through a substrate that is transparent to the laser beam, into a negative photoresist layer on the substrate. The negative photoresist layer may be subsequently developed to provide a master for optical and/or mechanical microstructures. Related systems, microstructure products and microstructure masters also are disclosed.

A video encoder and corresponding method are provided for mixed inter/intra encoding of a macroblock having a plurality of partitions, where the encoder includes a reference picture weighting applicator coupled with a reference picture weighting factor unit for assigning weighting factors corresponding to each of the inter and intra coded partitions, respectively; and the corresponding method for encoding a macroblock with several partitions includes inter-coding at least one partition and intra-coding at least a second partition.

According to one embodiment, a method for scrambling and descrambling program data comprises the receipt of a mating key generator message including a manufacturer identifier. The mating key generator message is transmitted to a first remote source identified by the manufacturer identifier. In response, a mating key is received from the first remote source. Then, the mating key is supplied to a second remote source, the mating key being subsequently used to encrypt a service key used for scrambling program data.

The invention is related to decoding of block wise coded video pictures. The determination of using de-blocking filtering between coded blocks is based on alternative characteristics compared to the characteristics used in H.264/AVC.

Puncture sequences S₁, S₂, etc. for code rates R₁, R₂, etc. less than a maximum code rate R_max are defined subsets of a maximum rate puncture sequence S_max that corresponds to the maximum code rate R_max. Each puncture sequence S_i for a code rate R_i is related to the puncture sequence S_i−1, of the previous code rate R_i−1, and preferably S₁⊂S₂⊂ . . . ⊂S_max−1⊂S_max. The puncture sequences are groups of one or more memory elements, each of which is a variable degree, a variable node location, a check degree, or a check node location. A method for deriving such a puncture sequence for variable code rates is also disclosed.

A method and apparatus for staggercasting includes encoding a first signal representing content having a time duration and a second signal also representing that content. A time delay period is specified for the time duration of the content. A composite signal, comprising the first and second encoded signals, is generated. In the composite signal the first encoded signal is delayed with respect to the second encoded signal by the time delay period for the time duration of the content. If an error is detected in the composite signal, then the received second encoded signal is decoded to produce the content, otherwise the delayed received first encoded signal is decoded to produce the content.

A time-stretched enhanced recording scope (TiSER) is described using time stretch analog-to-digital conversion in a real-time burst mode. A chirped optical signal is modulated in response to receiving segments of an input signal. The optical signal with its modulated input signal, is stretched through an optical medium and digitized to represent the waveform segment. TiSER provides ultra-fast real-time sampling within short segment bursts of the original input signal while providing an ability to detect non-repetitive events. Methods and apparatus are also described for providing real-time information about inter-symbol information (ISI), rapidly determining bit-error rates (BER), performing time-domain reflectometry (TDR), generating eye diagrams for serial data, facilitating digital correction of data, clock recovery, optical carrier phase recovery, and otherwise increasing the speed and/or accuracy of a diverse range of high-speed signal measurement and processing activities.

A system and method for selective wavelength interleaved filtering technique for analog to digital conversion (ADC) comprises a remote aperture for analog input, a modulator operable to transform the analog input into an initial optical signal, a photonic front end having high resolution optical filters operable to filter the optical signal into multiple subsequent optical signals and supply local oscillators for downconversion into electrical signals, a segmented subsystem having a plurality of ADCs, each operable to receive and convert one subsequent optical signal of the optical signals, and a memory buffer and process subsystem operable to reconstruct the converted subsequent optical signals into a digital representation of the analog input by executing reconstruction algorithms. Provision is made for compensation of distortions arising in the electrical to optical to electrical conversion process. The optical filters can include a self-registered filter wherein individual passbands are intrinsically aligned to one another.

A communications system includes an encoder that produces a plurality of redundant symbols. For a given key, an output symbol is generated from a combined set of symbols including the input symbols and the redundant symbols. The output symbols are generally independent of each other, and an effectively unbounded number of output symbols (subject to the resolution of the key used) can be generated, if needed. The output symbols are information additive such that a received output symbol is likely to provide additional information for decoding even when many symbols are already received. The output symbols are such that a collection of received output symbols can provide probabilistic information to support error correction. A decoder calculates check symbols from the output symbols received, wherein each check symbol is associated with one or more input symbols and redundant symbols For each received output symbol, the decoder updates a running total of estimated information content and, in one or more rounds, generates a probability distribution for each input symbol over all or some of the possible values of input symbols. This process may be repeated until, for all of the input symbols, one of the many possible values is much more probable than others, or the process may be repeated a predetermined number of rounds, or other criteria is met. The updating can take into account already decoded symbols, additional output symbols and the check symbols.

An apparatus and method of decoding coded video bitstreams is disclosed. The apparatus comprises a first processor and a second processor configured to operate in parallel. The main processor receives the coded video bitstream, parses it, and calls the second processor to decode the coded video bitstream to retrieve macroblock data. If an error occurs during decoding, the second processor signals the first processor, which can instruct the second processor to perform an error recovery routine. The first processor the performs dequantization and inverse DCT to recover digital pixel data from the macroblocks so that an image formed from the digital pixel data can be later displayed on a monitor.

An dual phase pulse modulation (DPPM) encoder circuit converts data into a series of high and low signal pulses, each of whose time durations or pulse widths represents a group of M data bits, with the alternating high and low pulses representing successive groups. The encoder circuit may include a set of parallel-in, serial-out shift registers that subdivide received data words into the M-bit groups, a state machine that specified the pulse durations for each received group, e.g., by incrementing a state that indicates selected signal pulse transition times, a system clock delay chain with multiple taps, a multiplexer controlled by the state machine for successively selecting different taps, and a toggle flip-flop that is clocked by the multiplexer output.

A method and apparatus for storing staggercasted content includes encoding a set of signals representing content. The set of signals is capable of being decoded to produce a corresponding set of decoded signals, each decoded signal having a quality different from the qualities of the decoded signals corresponding to the other encoded signals. A composite signal comprising the set of encoded signals, staggered in time, is generated. The set of encoded signals is extracted from the composite signal. Errors in the set of extracted encoded signals are detected to produce a subset of available extracted encoded signals which are not erroneous. A content representative signal at a selectable desired quality is decoded. The decoded content representative signal is then stored in a storage device.

An optical analog-to-digital converter (ADC) is disclosed which converts an input optical analog signal to an output optical digital signal at a sampling rate defined by a sampling optical signal. Each bit of the digital representation is separately determined using an optical waveguide interferometer and an optical thresholding element. The interferometer uses the optical analog signal and the sampling optical signal to generate a sinusoidally-varying output signal using cross-phase-modulation (XPM) or a photocurrent generated from the optical analog signal. The sinusoidally-varying output signal is then digitized by the thresholding element, which includes a saturable absorber or at least one semiconductor optical amplifier, to form the optical digital signal which can be output either in parallel or serially.

The invention discloses an on-chip integrated optical digital-to-analog converter based on a silicon-based nanowire waveguide. The on-chip integrated optical digital-to-analog converter comprises N laser devices, a modulation multiplex integral structure and a photoelectric detector. The modulation multiplex integral structure comprises a trunk waveguide L0, N cascaded silicon-based nanowire waveguide micro-ring resonators (MRR1, MRR2...MRRN) and N bent waveguides (L1, L2...LN), the N laser devices are connected with the uploading ends of the N bent waveguides (L1, L2...LN) respectively, the photoelectric detector is connected with the straight-through end of the trunk waveguide L0, and N is a natural number. According to the on-chip integrated optical digital-to-analog converter, the advantages that the silicon-based waveguide is compact in structure, low in power consumption, compatible with the CMOS process and the like are fully achieved, the high speed and high resolution in the DAC process can be achieved, and the integration and miniaturization of the optical DAC can be achieved.