Abstract: A construction method of fast-setting polymer grouting for rapid control of slope erosion and landslide.

Abstract: The disclosed systems and methods for detecting mirror crosstalk between frequency bands equally above and below the center frequency of a Digital Subcarrier Multiplexing system include: a transmitter configured to insert zero-power symbols on half the frequency bands below center frequency, and insert other zero-power symbols, partially overlapping in time with the first zero-power symbols, on the other half of the frequency bands above center frequency. A receiver zeroes out ASE and other noises during the overlapping portion of all the zero-power symbols, then uses the power detected during the remaining portion of each zero-power symbol in each frequency band to accurately evaluate the mirror crosstalk from the corresponding frequency band on the opposite side of center frequency.

Abstract: Methods and devices for IQ time skew and conjugation compensation and calibration of a coherent transmitter or transceiver are described. A pilot tone is combined with a digital data signal such that relative powers of the pilot tone in each of two frequency bands of the transmitted data signal may be detected by a pilot tone detector and used to calculate the time skew between I and Q modulation channels of the transmitter. A transmitter DSP applies IQ time skew bias to the data signal to compensate for any calculated IQ time skew. The pilot tone detector also provides the transmitter DSP with the information necessary to detect phase conjugation of the optical signal, which can be corrected by inverting the polarity of the data signal or changing the phase bias point of the optical modulator.

Abstract: Methods and systems for performing signal pre-correction of a transmission signal comprising a sequence of symbols using a Pattern Dependent Look-up Table (PDLUT) containing one or more distortion correction values. Upon accessing a distortion correction value from the PDLUT for a symbol of the sequence of symbols, the accessed distortion correction value is quantized into one or more quantized values according to one or more quantizations, thereby reducing the bit-width of the distortion correction value. The transmission signal and the distortion correction value with reduced bit-width may undergo linear correction compensation, such as through a finite impulse response (FIR) filter, independent of one another, where the one or more quantized correction values with reduced bit-width reduce a number of calculation steps performed during linear correction compensation resulting in power savings.

Abstract: Methods and systems for performing signal pre-correction of a transmission signal comprising a sequence of symbols using a Pattern Dependent Look-up Table (PDLUT) containing one or more distortion correction values. Upon accessing a distortion correction value from the PDLUT for a symbol of the sequence of symbols, the accessed distortion correction value is quantized into one or more quantized values according to one or more quantizations, thereby reducing the bit-width of the distortion correction value. The transmission signal and the distortion correction value with reduced bit-width may undergo linear correction compensation, such as through a finite impulse response (FIR) filter, independent of one another, where the one or more quantized correction values with reduced bit-width reduce a number of calculation steps performed during linear correction compensation resulting in power savings.

Abstract: Methods and apparatus for coherent transmitter calibration are provided that employ direct detection (DD) using one single photodetector (PD). The provided method and apparatus do not require hardware for coherent reception, or additional ADCs for quality control. An additional optical tone is added to a QAM optical signal that is outside the band of the QAM optical signal. The result of this is that after direct detection, there is a correlation between the real and imaginary parts, and the imaginary part can be recovered with a Hilbert transform. The estimated QAM optical signal obtained by direct detection is used to perform a transmitter factory calibration method to calibrate for one or more transmitter impairments and/or to perform in-line self-calibration.

Abstract: Methods and apparatuses for IQ time skew calibration in a coherent transceiver are described. A four-channel signal is received. A set of inputs is constructed for a 4×8 MIMO equalizer by converting the four-channel signal into four complex inputs that each have a phase shift corresponding to an estimated carrier frequency offset. The set of inputs further includes conjugate replicas of the four complex inputs. Using output from the 4×8 MIMO equalizer, equalizer coefficients are calculated by minimizing error between the MIMO output and a reference signal. Receiver and transmitter IQ skew are estimated using the equalizer coefficients, by converting the equalizer coefficients form the time domain to the frequency domain to determine receiver and transmitter IQ differential phase responses, which are indicative of respective receiver and transmitter IQ skew in the time domain. Skew compensation is then performed.

Abstract: Methods and devices for power imbalance compensation and calibration of a coherent transmitter or transceiver are described. A pilot tone is combined with a digital data signal such that relative amplitudes of the pilot tone in each of four transmitted optical data channels may be detected by a pilot tone detector and used to calculate any power imbalances between I/Q phase channels and/or X/Y polarized channels of the transmitter. The pilot tone detector applies gain to the data signal of the transmitter to compensate for any calculated power imbalances. Because the pilot tone is combined with the digital data signal, its amplitude in each received channel is proportional to the data signal power of that channel.

Abstract: The present disclosure relates to methods and apparatus for graphics processing. An example method generally includes receiving, at a graphics processing unit (GPU), a plurality of commands corresponding to a plurality of draws across a frame, each of the plurality of commands indicating a depth test direction with respect to a low-resolution depth (LRZ) buffer for the corresponding draw. The method generally includes maintaining, at the GPU, a LRZ status buffer to store a corresponding depth test direction for a first command in time of the plurality of commands processed by the GPU. The method generally includes disabling, at the GPU, use of the LRZ buffer for depth testing for any of the plurality of commands remaining unprocessed after processing a command of the plurality of commands having a different depth test direction than the corresponding depth test direction stored in the LRZ status buffer.

Abstract: Optical transmitters, receivers, and methods are described in an optical network. An optical transmitter comprises an encoder configured to receive an input data stream and to encode the input data stream into a signal. The signal is defined as a sequence of regular units, and a rotator is configured to receive each unit of the signal and to output, for each given input unit with an input state of polarization (SOP), a respective given output unit associated with an output SOP. The output SOP of the given output unit is different from a corresponding output SOP of each other output unit that is immediately adjacent to the given output unit. The output SOPs of the units in a transmitted signal may form an alternating pattern (or other repeating pattern), which may help to lower the average BER, in particular, due to forward error correction (FEC).

Abstract: Methods and apparatuses for IQ time skew calibration in a coherent transceiver are described. A four-channel signal is received. A set of inputs is constructed for a 4×8 MIMO equalizer by converting the four-channel signal into four complex inputs that each have a phase shift corresponding to an estimated carrier frequency offset. The set of inputs further includes conjugate replicas of the four complex inputs. Using output from the 4×8 MIMO equalizer, equalizer coefficients are calculated by minimizing error between the MIMO output and a reference signal. Receiver and transmitter IQ skew are estimated using the equalizer coefficients, by converting the equalizer coefficients form the time domain to the frequency domain to determine receiver and transmitter IQ differential phase responses, which are indicative of respective receiver and transmitter IQ skew in the time domain. Skew compensation is then performed.

Abstract: The disclosed systems, apparatuses and methods are directed to controlling a difference between a first center frequency of a first optical subcarrier and a second center frequency of a second optical subcarrier of an optical super-channel signal in an optical network. The method comprises modulating the first optical subcarrier at a first optical side component frequency with a first side modulation frequency and modulating the second optical subcarrier at a second optical side component frequency with a second side modulation frequency. The method further comprises detecting a radio-frequency (RF) power at a modulated beat frequency tone in the modified optical signal.

Abstract: Methods and apparatus for coherent transmitter calibration are provided that employ direct detection (DD) using one single photodetector (PD). The provided method and apparatus do not require hardware for coherent reception, or additional ADCs for quality control. An additional optical tone is added to a QAM optical signal that is outside the band of the QAM optical signal. The result of this is that after direct detection, there is a correlation between the real and imaginary parts, and the imaginary part can be recovered with a Hilbert transform. The estimated QAM optical signal obtained by direct detection is used to perform a transmitter factory calibration method to calibrate for one or more transmitter impairments and/or to perform in-line self-calibration.

Abstract: The disclosed systems, structures, and methods are directed to monitoring performance of optical networks. Transmitted and received optical channel signal has both low-power gaps and an amplitude modulation pilot tone applied. The low-power gaps are applied at a gap frequency with gap power being lower than a signal power of the optical channel signal. The pilot tone is applied to the optical channel signal at a pilot tone modulation frequency, which is different from the gap frequency. Described methods include determining pilot tone modulation depth based on detected gap power in low-power gaps of the received optical channel signal. Amplifier spontaneous emission and nonlinear noise in optical link are detected separately. This permits determining and monitoring of optical signal-to-noise ratio.

Abstract: The disclosed systems, apparatuses and methods are directed to controlling a difference between a first center frequency of a first optical subcarrier and a second center frequency of a second optical subcarrier of an optical super-channel signal in an optical network. The method comprises modulating the first optical subcarrier at a first optical side component frequency with a first side modulation frequency and modulating the second optical subcarrier at a second optical side component frequency with a second side modulation frequency. The method further comprises detecting a radio-frequency (RF) power at a modulated beat frequency tone in the modified optical signal.

Abstract: The present disclosure relates to methods and apparatus for graphics processing. In some aspects, multiple processing units can be in a graphics processing pipeline of a GPU. The apparatus can also group the multiple processing units into one or more processing unit clusters. In some aspects, each of the one or more processing unit clusters can correspond to one or more context registers. Additionally, the apparatus can determine one or more context states of the one or more context registers in each of the one or more processing unit clusters. Also, the apparatus can implement one or more execution counters corresponding to at least one of the one or more processing unit clusters in the graphics processing pipeline, where each of the one or more execution counters includes an execution value.

Abstract: The present disclosure relates to methods and apparatus of operation of a processing unit. The apparatus can update a first context register of one or more context registers based on a first programming state. In some aspects, the one or more context registers can be associated with at least one processing unit cluster in a graphics processing pipeline of the processing unit. The apparatus can execute a first draw call function corresponding to the first programming state. The apparatus can determine whether at least one additional first draw call function corresponds to the first programming state. In some aspects, the at least one additional first draw call function can follow the first draw call function in the graphics processing pipeline. Also, the apparatus can execute the at least one additional first draw call function when the at least one additional first draw call function corresponds to the first programming state.

Abstract: The present disclosure relates to methods and apparatus of operation of a processing unit. The apparatus can update a first context register of one or more context registers based on a first programming state. In some aspects, the one or more context registers can be associated with at least one processing unit cluster in a graphics processing pipeline of the processing unit. The apparatus can execute a first draw call function corresponding to the first programming state. The apparatus can determine whether at least one additional first draw call function corresponds to the first programming state. In some aspects, the at least one additional first draw call function can follow the first draw call function in the graphics processing pipeline. Also, the apparatus can execute the at least one additional first draw call function when the at least one additional first draw call function corresponds to the first programming state.

Abstract: The disclosed systems, structures, and methods are directed to monitoring performance of optical networks. Transmitted and received optical channel signal has both low-power gaps and an amplitude modulation pilot tone applied. The low-power gaps are applied at a gap frequency with gap power being lower than a signal power of the optical channel signal. The pilot tone is applied to the optical channel signal at a pilot tone modulation frequency, which is different from the gap frequency. Described methods include determining pilot tone modulation depth based on detected gap power in low-power gaps of the received optical channel signal. Amplifier spontaneous emission and nonlinear noise in optical link are detected separately. This permits determining and monitoring of optical signal-to-noise ratio.

Abstract: In a powered device (PD), four MOSFETs are used in a rectifier circuit. The four MOSFETs are disposed based on a premise that an electric potential of a contact pair 1-2 is lower than that of a contact pair 3-6 and an electric potential of a contact pair 7-8 is lower than that of a contact pair 4-5, so that a PoE current of each contact group passes through only two of the MOSFETs but does not pass through a diode.