Abstract: Methods, apparatuses, and systems are presented for performing adaptive equalization involving receiving a signal originating from a channel associated with inter-symbol interference, filtering the signal using a filter having a plurality of adjustable tap weights to produce a filtered signal, and adaptively updating each of the plurality of adjustable tap weights to a new value to reduce effects of inter-symbol interference, wherein each of the plurality of adjustable tap weights is adaptively updated to take into account a constraint relating to a measure of error in the filtered signal and a constraint relating to group delay associated with the filter. Each of the plurality of adjustable tap weights may be adaptively updated to drive group delay associated with the filter toward a target group delay.

Abstract: Methods, apparatuses, and systems are presented for performing channel equalization comprising receiving a signal from a channel associated with inter-symbol interference, processing the received signal to effectively apply a plurality of linearly independent impulse responses to the received signal to produce a plurality of intermediate signals, scaling each of the intermediate signals by each of a plurality of multiplier factors to produce a plurality of scaled signals, and combining the scaled signals to produce a resulting signal corresponding to an equalized version of the received signal in order to reduce effects of inter-symbol interference.

Abstract: Methods, apparatuses, and systems are presented for performing channel equalization involving receiving a signal from a channel associated with inter-symbol interference (ISI), providing the received signal to an LCR network comprising a plurality of inductors and a plurality of capacitors, generating in the LCR network a first plurality of intermediate signals representing voltages associated with capacitors in the LCR network and a second plurality of intermediate signals representing currents associated with inductors in the LCR network, wherein the first plurality and second plurality of intermediate signals correspond to application of linearly independent impulse responses to the received signal, applying a corresponding one of a plurality of multiplier factors to each of the first plurality and second plurality of intermediate signals, and generating from the LCR network a resulting signal corresponding to an equalized version of the received signal.

Abstract: A method and apparatus for producing high-frequency oscillations is disclosed. A new resonator architecture minimizes via losses and supports a compact layout of active circuitry. The resonator architecture incorporates dual resonant transmission lines to reduce resonator loss and facilitate compact layout. The oscillations of two oscillators are cross-coupled in a way that compensates for the delay in the active devices of the oscillator, thus permitting accurate alignment of the active circuitry response with the oscillation waveform. The cross-coupling of the two oscillators improves phase noise performance and eliminates spurious oscillations. An active circuit architecture provides very narrow pulses for the operation of the oscillator. This architecture provides for accurate cross-coupling and pulsed-mode operation to improve manufacturing stability and phase noise performance.

Abstract: A method and apparatus for eliminating dead zone in a phase locked loop with binary quantized detectors are described. Dead zone can be eliminated by changing the threshold used to quantize the cross point sample. A quantized cross point sample is integrated in order to set a new threshold. The integration may be performed during data transitions to eliminate threshold drift during long sequences where no transitions occur.

Abstract: The system includes a receiver for receiving a bit stream; an error monitor for indicating a first error rate for a first set of data received in the bit stream; and an adjustable circuit for converting an incoming signal into the bit stream using a reference signal that is modulated using a control signal. The system also includes a subsystem for correlating the first error rate and the control signal to generate the reference signal. The control signal has an amplitude that is selected so that a second set of data received in the bit stream has a second error rate that is less than the first error rate.

Abstract: A method for performing adaptive equalization is presented comprising receiving a Forward Error Correction (FEC) encoded signal from a channel, filtering the received FEC encoded signal using a filter according to at least one adjustable filter coefficient to produce a filtered signal, evaluating the filtered signal to generate a signal error output, adjusting the at least one adjustable filter coefficient in response to the signal error output, performing FEC decode processing dependent on the filtered signal to generate an FEC output, and adjusting the at least one adjustable filter coefficient in response to the FEC output. In one embodiment, the signal error output relates to Mean Squared Error (MSE), and the FEC output relates to bit error rate. The at least one adjustable filter coefficient may be first adjusted in response to the signal error output until a specified condition is met, then adjusted in response to the FEC output.

Abstract: Improved high-speed adaptive equalization is presented that may involve converting an optical signal into an electrical signal and performing equalization by (i) filtering the electrical signal with an analog filter according to at least one filter coefficient to produce a filtered output, (ii) generating an error signal from the filtered output according to an error function, (iii) providing at least one control signal to the analog filter for adjusting the at least one filter coefficient, (iv) detecting a relationship between a change in the at least one filter coefficient and a change in the error signal, and (v) adjusting the at least one filter coefficient according to the relationship to minimize the error signal. The least one coefficient may comprise a plurality of coefficients, and the relationship may be a gradient estimate having multiple components, each determined by varying only one of the coefficients and detecting a resulting change in the error signal.

Abstract: The invention discloses phase-shifters, modulators, and method that produces a smaller &pgr; by means of a field excitation using multiple electrodes. A negative signal is introduced that travels with the positive signal, which enhances the electric field significantly. The field enhancement is provided by the superposition of the fields accumulated from each electrode. A base or substrate material can be made from any compound having linear electro-optic properties, such as lithium niobate, lithium tantalite, potassium lithium niobate, potassium titanyl phosphate or gallium-arsenide. For lithium niobate, there are two possible orientations of electric field, z-cut orientation or x-cut orientation.

Abstract: A method and apparatus for producing high-frequency oscillations is disclosed. A new resonator architecture minimizes via losses and supports a compact layout of active circuitry. The resonator architecture incorporates dual resonant transmission lines to reduce resonator loss and facilitate compact layout. The oscillations of two oscillators are cross-coupled in a way that compensates for the delay in the active devices of the oscillator, thus permitting accurate alignment of the active circuitry response with the oscillation waveform. The cross-coupling of the two oscillators improves phase noise performance and eliminates spurious oscillations. An active circuit architecture provides very narrow pulses for the operation of the oscillator. This architecture provides for accurate cross-coupling and pulsed-mode operation to improve manufacturing stability and phase noise performance.

Abstract: An integrated high-speed package comprising a package housing having a housing lip and connector having a center pin abutting along a bottom surface of the housing lip. For signal registration of a first substrate to the signal lead, the substrate is “floated” up to the housing lip, which provides an alignment reference to ensure that the top surface of the first substrate is aligned and in direct registration with the signal lead. In another embodiment, the center pin to substrate registration is provided at a top surface of a housing base. The housing base preferably comprises a first portion of a first height and a second portion of a second height. Accordingly, the housing base can accommodate substrates of different thickness while allowing a top surface of the first and a second substrate to be coplanar to facilitate signal registration there between.

Abstract: The invention discloses phase-shifters, modulators, and method that produces a smaller &pgr; by means of a field excitation using multiple electrodes. A negative signal is introduced that travels with the positive signal, which enhances the electric field significantly. The field enhancement is provided by the superposition of the fields accumulated from each electrode. A base or substrate material can be made from any compound having linear so electro-optic properties, such as lithium niobate, lithium tantalite, potassium lithium niobate, potassium titanyl phosphate or gallium-arsenide. For lithium niobate, there are two possible orientations of electric field, z-cut orientation or x-cut orientation.

Abstract: A method and system to compensate for DC and low frequency current produced by a photodiode that is illuminated with an optical data stream is described. An optical data stream ideally produces no current from a photodiode when the bit is a 0 and produces a current proportional to the optical power when the bit is a 1. Thus, the current produced from the photodiode consists of a DC component, which is typically half the current of a 1 bit (if there is an equal number of 1s and 0s in the data), and a high frequency component that carries the data. The DC component can interfere with the signal path's ability to process the information carrying component of the photodiode current, by causing a fixed offset to propagate and be amplified through it. This offset distorts the voltage signal at the output of the signal path, and must therefore be cancelled early in the path; usually in the first transimpedance stage or just after it.

Abstract: Method and system for a programmable analog tapped delay line filter are disclosed. One embodiment of the present invention is a programmable analog tapped delay line filter comprising an input line, an output line, and one or more gaincells or taps coupled between the input line and the output line. The input and output lines each comprises a cascade of one or more differential delay cells, and each of the one or more gaincells or taps corresponds to a tap weight or coefficient. Furthermore, the input and output lines are terminated in impedances and the filter produces one or more outputs.

Abstract: An optical data transmission system using a Mach Zehnder (M-Z) modulator asymmetrically modulates the optical carrier to generate control information to optimize the transmitted optical signal.