Crystal Semiconductor Corporation

Lucent Technologies Inc.

Draker, Inc.

Cirrus Logic Inc.

Agere Systems Inc.

Shawn R McCaslin

Nariankadu Datatreya Hemkumar

Mandeep Singh Chadha

Bertrand Jeffery Williams

Mile Milisavljevic

Bheeshmar Redheendran

Nicholas R Van Bavel

Zhuo Fu

Sam Brandon Sandbote

Hakim M Mesiwala

John Camagna

Mandeep Chadha

A converter unit configured to couple to a photovoltaic panel (PV) may include a controller to sense an output voltage and output current produced by the photovoltaic panel, and manage the output voltage of a corresponding power converter coupled to a DC bus to regulate the resultant bus voltage to a point that reduces overall system losses, and removes non-idealities when the panels are series connected. The controller may also adapt to output condition constraints, and perform a combination of input voltage and output voltage management and regulation, including maximum power point tracking (MPPT) for the PV. The output voltage and output current characteristic of the power converter may be shaped to present a power gradient&#x2014;which may be hysteretically controlled&#x2014;to the DC bus to compel an inverter coupled to the DC bus to perform its own MPPT to hold the DC-bus voltage within a determinate desired operating range.

Regulation of inverter DC input voltage in photovoltaic arrays

A converter unit configured to couple to a photovoltaic panel (PV) may include a controller to sense an input voltage and input current obtained from the photovoltaic panel, and manage the output voltage of a corresponding power converter coupled to a DC bus to regulate the resultant bus voltage to a point that reduces overall system losses, and removes non-idealities when the panels are series connected. The controller may also perform input voltage management and regulation, including maximum power point tracking (MPPT) for the PV. The controller may probe the bus voltage using a probe waveform generated according to a pseudo-random bit sequence (PRBS), to provide a probe signal that is distinct from the control steps performed by the controller. A PV array may feature a respective converter unit coupled to each PV, with each respective controller using a different and unique seed for generating its PRBS.

Pseudo-random bit sequence generation for maximum power point tracking in photovoltaic arrays

An echo canceling system, method of attenuating echo, and a bit pump and transceiver employing the system and method. The echo canceling system is couplable between a transmit and receive path of the bit pump and receives and attenuates the echo in a receive signal propagating along the receive path. In one embodiment, the echo canceling system includes a slave echo canceling stage that employs a filter coefficient to attenuate the echo. The echo canceling system also includes a separation circuit, coupled to the slave echo canceling stage, that generates data representing a residual echo substantially exclusive of the receive signal. The echo canceling system still further includes a master echo canceling stage, coupled to the separation circuit, that receives the data and modifies the filter coefficient based thereon.

Echo canceling system for a bit pump and method of operating the same

A separation circuit, method of determining a residual level of an echo, and an echo canceling system, bit pump and transceiver employing the circuit and method. The echo canceling system employing the separation circuit is couplable between a transmit and receive path of the bit pump and generates an echo canceling signal. In one embodiment, the separation circuit includes a symbol determination circuit that accepts a receive signal, propagating along the receive path, substantially free of an echo and determines a symbol associated with the receive signal. The separation circuit also includes an estimator stage, coupled to the symbol determination circuit, that receives the symbol and provides an estimated receive signal. The separation circuit generates data representing a residual level of the echo as a function of the estimated receive signal and the echo canceling signal.

Separation circuit for an echo canceling system and method of operating the same

A filter circuit, method of configuring the filter circuit, and a bit pump and transceiver employing the circuit and method. In one embodiment, the filter circuit includes a noise prediction equalizer that generates a noise prediction equalizer coefficient during activation of the bit pump to reduce an intersymbol interference associated with a receive signal propagating along a receive path of the bit pump. The filter circuit also includes a decision feedback equalizer that generates a decision feedback equalizer coefficient during the activation of the bit pump to reduce the intersymbol interference associated with the receive signal. The noise prediction equalizer is concatenated with the decision feedback equalizer during showtime of the bit pump to form a precoder associated with a transmit path of the bit pump.

Filter circuit for a bit pump and method of configuring the same

An adaptive filter is provided which has fixed point or floating point data stored in a data RAM (74) and block scale floating point coefficients stored in a coefficient RAM (84). The data and coefficients are utilized in a filter algorithm which utilizes a multiplier and an accumulator to provide a convolution result. Coefficients are updated by adding the multiplied result of the data RAM value and the error value to the old value of the coefficient. This is done for all the coefficient values in the coefficient RAM. The error value indicates the difference between the filter output and the sampled near-end signal that is the echo. These new coefficients are examined and if any have a value above or all have a value below a predetermined threshold, then the mantissas of all the coefficients are shifted and the exponent adjusted in the next filter cycle.

Adaptive filter system having mixed fixed point or floating point and

A signal detector for detecting the presence of a intermittent signal component in a signal. The signal detector receives each of the signal strength samples during a corresponding iteration, and compares a threshold value with the received signal sample. The signal detector sets a counter to a pre-determined number if the sample compared is greater than the threshold value. The signal detector decrements the persistence counter if a corresponding sample is not greater than the threshold value. If the persistence counter is greater than a trigger value, the detector indicates the presence of a intermittent signal component or otherwise declares the absence of a intermittent signal component. The detector may indicate the presence of a intermittent signal component by a logical value of 1 and the absence by a logical value of 0. The threshold value is composed of two components; the intermittent signal component and the background signal component. Each of the components of the threshold is determined separately by using a tracker and a low pass estimator under a control signal obtained from previous decisions as to whether intermittent signal was present or absent.

Persistence and dynamic threshold based intermittent signal detector

A double-talk detector for an echo canceller includes power estimators (60) and (62) which are utilized to measure the ERLE value in a calculator (64). This ERLE is stored in a register (70) when it is the largest value generated. This register (70) is updated whenever a new and better ERLE occurs. A fraction of the value in register (70) is utilized as an input to a comparator (88), and then compared to the current ERIE value. If the current ERLE differs from the SERLE in register (70) an inhibit signal is generated for blocking the updates of an adaptive filter (40). The value stored in the register (70) is periodically decremented to reduce the value thereof. This decrement operation is performed in response to detection of an utterance from the far-end. A half-Duplex operation is provided with two attentuators (352) and (354) to provide a switching operation and allow only one side access to the communication path. Speech, or the occurrence of an utterance is monitored at each end by comparing the raw input power at each end to a scaled up background noise power for that end. Different scaling factors for speech detection, or utterance detection, are provided, there being a high scaling factor and a low scaling factor. The side with the initially detected utterance will have access to the system and have the lowest scaling factor associated therewith, the other having the highest scaling factor associated therewith.

Half-duplex controller

A variable gain echo suppressor is provided that utilizes two variable attenuators (410) and (412) that are disposed in the receive and transmit paths, respectively, of a communication system. An echo suppressor (414) receives the input from the far end and transmits the output from the near end and controls the two attenuators to set a variable gain therein. The echo suppressor utilizes a normalized power level which is normalized with respect to the background noise at the respective end and then takes the ratio of this normalized power and the normalized power at the opposite end to define an associated power ratio. This power ratio value is utilized to determine the attenuation for the associated end. When the power ratio is high, this indicates that a stronger signal is being received from that end and a small amount of attenuation is associated in the transmit path from that end. When they aye equal, this will result in both systems having approximately the same attenuation, a mid-level attenuation. This is provided through a look up table (450) for the far end and a look up table (452) for the near end. Additionally, the signal power is derived from a peak detection IIR filter (420) and (428) which has the characteristics thereof changed as a function of the power ratio. This is achieved by changing the value of the pole in the IIR filter.

Variable gain echo suppressor

A double-talk detector for an echo canceller includes power estimators (60) and (62) which are utilized to measure the ERLE value in a calculator (64). This ERLE value is stored in a register (70) when it is the largest value generated. This register (70) is updated whenever a new and better ERLE occurs. A fraction of the value in register (70) is utilized as an input to a comparator (88), and then compared to the current ERLE value. If the current ERLE differs from the SERLE in register (70) an inhibit signal is generated for blocking the updates of an adaptive filter (40). The value stored in the register (70) is periodically decremented to reduce the value thereof. This decrement operation is performed in response to detection of an utterance from the far-end.

Growing community of inventors

Austin, TX, United States of America

Shawn R McCaslin