Abstract: Aspects of a method and system for feedback during optical communications are provided. In one embodiment, a system for optical communications comprises a digital-to-analog converter (DAC), a driver, and a transmit optical subsystem. The DAC is operable to receive a digital code of a plurality of digital codes and output an analog current signal having an analog current level of a plurality of analog current levels. The driver is operable to condition the analog current signal output from the digital-to-analog converter. The transmit optical subsystem is operable to generate an optical signal from the conditioned analog current signal. A digital modification of an input digital signal is dynamically controlled by a feedback path according to one or more characteristics of the optical signal. The one or more characteristics comprise a nonlinearity that may be temperature dependent.

Abstract: An integrated circuit may comprise a tuner operable to digitize a band of frequencies comprising a plurality of television channels, a crossbar operable to select one or more of the plurality of television channels output by the tuner, a plurality of demodulators operable to receive the selected one or more television channels from the crossbar and demodulate the selected one or more television channels to recover a plurality of transport streams, a transport module operable to multiplex the plurality of transport streams into a single packet stream, and a framer operable to: encapsulate packets of the plurality of transport streams into transport stream frames of a serial datastream, and insert filler frames into the serial datastream after every Nth transport stream frame of the serial datastream, where N is an integer.

Abstract: Methods and systems for time interleaved analog-to-digital converter timing mismatch calibration and compensation may include receiving an analog signal on a chip, converting the analog signal to a digital signal utilizing a time interleaved analog-to-digital-converter (ADC), and reducing a blocker signal that is generated by timing offsets in the time interleaved ADC by estimating complex coupling coefficients between a desired digital output signal and the blocker signal utilizing a decorrelation algorithm on frequencies within a desired frequency bandwidth. The decorrelation algorithm may comprise a symmetric adaptive decorrelation algorithm. The received analog signal may be generated by a calibration tone generator on the chip. An aliased signal may be summed with an output signal from a multiplier. The complex coupling coefficients may be determined utilizing the decorrelation algorithm on the summed signals.

Abstract: Methods and systems for multi-path video and network channels may comprise a communication device comprising a wideband tuner (WB) and a narrowband tuner (NB). A video channel and a network channel may be received in the WB when the device is operating in a first stage. A video channel and a network channel may be received in the WB and the network channel may also be received in the NB when the device is operating in a second stage. The network channel may be received in the NB when the device is operating in a third stage. The reception of the network channel from both the WB and NB may enable a continuous reception of the network channel in a transition between the first and third stages. The WB may be operable to receive a plurality of channels and the NB may be operable to receive a single channel.

Abstract: Methods and systems are provided for adaptive guard interval (GI) combining. When a signal carrying at least one symbol that is preceded by a guard interval that comprises a portion of the symbol is received, a portion of the guard interval that is free from inter-symbol interference (ISI) may be determined, and only a part of the ISI-free portion of the guard interval may be extracted. The part of the ISI-free portion of the guard interval may be selected based on timing adjustment, relative to start of the symbol, that is applied to a function used in extracting the symbol. The extracted part of the ISI-free portion of the guard interval may then be combined with a corresponding portion of the symbol. The extracting and/or combining may be performed after a determination that a delay spread is smaller than a predetermined channel delay.

Abstract: Methods and systems are provided for using priori knowledge of noise in controlling signal receivers. In a signal receiver, one or more adjustments, relating to generating output signals via the signal receiver, may be determined, with the adjustments directed to one or more particular components of the output signals. When applying the adjustments is determined to cause undesired effects on one or more other components of the output signals, with these other components being intended to remain unchanged when the adjustments are applied, operations of the signal receiver may be controlled based on the undesired effects, with the controlling including mitigating at least some of the effects on the one or more other components of the signals when the one or more adjustments are applied. The adjustments may include frequency re-assignment. The undesired effects may include one or more of amplitude glitches, phase glitches, bit or packet errors, etc.

Abstract: Aspects of a method and system for feedback during optical communications are provided. In one embodiment, a system for optical communications comprises a digital-to-analog converter (DAC), a driver, and a transmit optical subsystem. The DAC is operable to receive a digital code of a plurality of digital codes and output an analog current signal having an analog current level of a plurality of analog current levels. The driver is operable to condition the analog current signal output from the digital-to-analog converter. The transmit optical subsystem is operable to generate an optical signal from the conditioned analog current signal. A digital modification of an input digital signal is dynamically controlled by a feedback path according to one or more characteristics of the optical signal. The one or more characteristics comprise a nonlinearity that may be temperature dependent.

Abstract: An electronic receiver may generate a differential detection sequence based on a received symbol sequence and based on a m-symbol delayed version of the received symbol sequence, where in is an integer greater than 1. The particular differential detection sequence may be a result of an element-by-element multiplication of the particular received symbol sequence and the conjugate of an in-symbol delayed version of the particular received symbol sequence. The receiver may calculate differential decision metrics based on the differential detection sequence and based on a set of differential symbol sequences generated from the set of possible transmitted symbol sequences. The receiver may generate a decision as to which of a set of possible transmitted symbol sequences resulted in the received symbol sequence, where the decision is based on the differential decision metrics and the set of possible transmitted symbols sequences.

Abstract: Methods and systems for time interleaved analog-to-digital converter timing mismatch calibration and compensation may include receiving an analog signal on a chip, converting the analog signal to a digital signal utilizing a time interleaved analog-to-digital-converter (ADC), and reducing a blocker signal that is generated by timing offsets in the time interleaved ADC by estimating complex coupling coefficients between a desired digital output signal and the blocker signal utilizing a decorrelation algorithm on frequencies within a desired frequency bandwidth. The decorrelation algorithm may comprise a symmetric adaptive decorrelation algorithm. The received analog signal may be generated by a calibration tone generator on the chip. An aliased signal may be summed with an output signal from a multiplier. The complex coupling coefficients may be determined utilizing the decorrelation algorithm on the summed signals.

Abstract: A signal receiver may be configured to determine when signal generation adjustments directed to particular components of signals received by the signal receiver, cause performance changes relating to effects of the signal generation adjustments on other components of the received signals. Operations of the signal receiver may then be controlled based on the performance changes, to mitigate at least some of the effects on the one or more other components of the signals. The performance changes may comprise amplitude glitches, phase glitches, and/or bit or packet errors. The signal generation adjustments may comprise channel-to-frequency re-assignment. Controlling operations of the signal receiver may comprise adjusting such parameters as amplification gain and/or tracking loop bandwidth, and/or determining whether (or not) to ignore bit/packet errors.

Abstract: An electronic receiver may generate a differential detection sequence based on a received symbol sequence and based on a m-symbol delayed version of the received symbol sequence, where m is an integer greater than 1. The particular differential detection sequence may be a result of an element-by-element multiplication of the particular received symbol sequence and the conjugate of an m-symbol delayed version of the particular received symbol sequence. The receiver may calculate differential decision metrics based on the differential detection sequence and based on a set of differential symbol sequences generated from the set of possible transmitted symbol sequences. The receiver may generate a decision as to which of a set of possible transmitted symbol sequences resulted in the received symbol sequence, where the decision is based on the differential decision metrics and the set of possible transmitted symbols sequences.

Abstract: Methods and systems for time interleaved analog-to-digital converter timing mismatch calibration and compensation may include receiving an analog signal on a chip, converting the analog signal to a digital signal utilizing a time interleaved analog-to-digital-converter (ADC), and reducing a blocker signal that is generated by timing offsets in the time interleaved ADC by estimating complex coupling coefficients between a desired digital output signal and the blocker signal utilizing a decorrelation algorithm on frequencies within a desired frequency bandwidth. The decorrelation algorithm may comprise a symmetric adaptive decorrelation algorithm. The received analog signal may be generated by a calibration tone generator on the chip. An aliased signal may be summed with an output signal from a multiplier. The complex coupling coefficients may be determined utilizing the decorrelation algorithm on the summed signals.

Abstract: Methods and systems for repurposing of a global navigation satellite system receiver for receiving low-earth orbit (LEO) communication satellite timing signals may comprise receiving a medium Earth orbit (MEO) satellite signal and/or a LEO signal in a receiver of the communication device. The MEO or LEO signal may be down-converted, and a position of the communication device may be calculated utilizing the down-converted signal. The signal may be down-converted utilizing a local oscillator signal generated by a phase locked loop (PLL), which may be delta-sigma modulated via a fractional-N divider. A clock signal may be communicated to the PLL utilizing a temperature-compensated crystal oscillator. The signal may be down-converted to an intermediate frequency or down-converted directly to baseband frequencies. The signal may be processed utilizing surface acoustic wave (SAW) filters. In-phase and quadrature signals may be processed in the RF path utilizing a two-stage polyphase filter.

Abstract: A system comprises a microwave backhaul outdoor unit having a first resonant circuit, phase error determination circuitry, and phase error compensation circuitry. The first resonant circuit is operable to generate a first signal characterized by a first amount of phase noise and a first amount of temperature stability. The phase error determination circuitry is operable to generate a phase error signal indicative of phase error between the first signal and a second signal, wherein the second signal is characterized by a second amount of phase noise that is greater than the first amount of phase noise, and the second signal is characterized by a second amount of temperature instability that is less than the first amount of temperature instability. The phase error compensation circuitry is operable to adjust the phase of a data signal based on the phase error signal, the adjustment resulting in a phase compensated signal.

Abstract: An integrated circuit may comprise a tuner operable to digitize a band of frequencies comprising a plurality of television channels, a crossbar operable to select one or more of the plurality of television channels output by the tuner, a plurality of demodulators operable to receive the selected one or more television channels from the crossbar and demodulate the selected one or more television channels to recover a plurality of transport streams, a transport module operable to multiplex the plurality of transport streams into a single packet stream, and a framer operable to: encapsulate packets of the plurality of transport streams into transport stream frames of a serial datastream, and insert filler frames into the serial datastream after every Nth transport stream frame of the serial datastream, where N is an integer.

Abstract: A GPS receiver includes an RF front end for acquiring and tracking a satellite signal and a baseband processor configured to preserve power. The baseband processor includes a GPS engine configured to process the satellite signal and generate a PVT fix, a power supervisory module for receiving the PVT fix, and a user state module that determines an environmental state, wherein the power supervisory module may power down the GPS receiver for a period of time based on a result of the determined environment state. The baseband processor also includes a time-based management module that adjusts the TCXO in response to the determined environmental state. The GPS receiver includes a plurality of operation modes, each of which is associated with a plurality of tracking profiles.

Abstract: Systems and methods for adjusting timing in a communication system, such as an OFDM system are described. In one implementation an error signal is generated to adjust the timing of a variable rate interpolator so as to adjust FFT timing. The error signal may be based on detection of significant peaks in an estimate of the impulse response of the channel, with the peak locations being tracked over subsequent symbols and the system timing adjusted in response to changes in the peaks.

Abstract: A system comprises a microwave backhaul outdoor unit having a first resonant circuit, phase error determination circuitry, and phase error compensation circuitry. The first resonant circuit is operable to generate a first signal characterized by a first amount of phase noise and a first amount of temperature stability. The phase error determination circuitry is operable to generate a phase error signal indicative of phase error between the first signal and a second signal, wherein the second signal is characterized by a second amount of phase noise that is greater than the first amount of phase noise, and the second signal is characterized by a second amount of temperature instability that is less than the first amount of temperature instability. The phase error compensation circuitry is operable to adjust the phase of a data signal based on the phase error signal, the adjustment resulting in a phase compensated signal.

Abstract: Methods and systems for time interleaved analog-to-digital converter timing mismatch calibration and compensation may include receiving an analog signal on a chip, converting the analog signal to a digital signal utilizing a time interleaved analog-to-digital-converter (ADC), and reducing a blocker signal that is generated by timing offsets in the time interleaved ADC by estimating complex coupling coefficients between a desired digital output signal and the blocker signal utilizing a decorrelation algorithm on frequencies within a desired frequency bandwidth. The decorrelation algorithm may comprise a symmetric adaptive decorrelation algorithm. The received analog signal may be generated by a calibration tone generator on the chip. An aliased signal may be summed with an output signal from a multiplier. The complex coupling coefficients may be determined utilizing the decorrelation algorithm on the summed signals.

Abstract: Methods and systems for multi-path video and network channels may comprise a communication device comprising a wideband tuner (WB) and a narrowband tuner (NB). A video channel and a network channel may be received in the WB when the device is operating in a first stage. A video channel and a network channel may be received in the WB and the network channel may also be received in the NB when the device is operating in a second stage. The network channel may be received in the NB when the device is operating in a third stage. The reception of the network channel from both the WB and NB may enable a continuous reception of the network channel in a transition between the first and third stages. The WB may be operable to receive a plurality of channels and the NB may be operable to receive a single channel.