Abstract: An adaptive coefficient signal generator for use in an adaptive signal equalizer with fractionally-spaced feedback. The signals representing the feedback tap coefficients are generated in conjunction with a timing interpolation parameter such that the fractionally-spaced feedback circuitry dynamically emulates symbol-spaced feedback circuitry.

Abstract: Systems and methods are disclosed to adaptively generate coefficients for continuous time least mean square error equalizers and to correct offset in high-gain amplifiers. An adaptive coefficient generator includes a bank of individual coefficient generators, each utilizing a first adaptive correction signal for a first correction and a second adaptive correction signal for a second more precise correction. The adaptive correction signals for offset correction can be a current or voltage. The first adaptive correction signal is set by maintaining the second adaptive correction signal constant, such as setting it to zero, and adjusting the first signal until the magnitude of the coefficient is minimized. The second adaptive correction signal is then set by maintaining the first adaptive correction signal at its set value by adjusting the second signal until the magnitude of the coefficient is again minimized.

Abstract: A low-voltage constrained coefficient adaptation and multiplication is provided. To provide the constrained coefficient adaptation, an adder adds an adaptive differential control voltage to a forcing differential control voltage to provide an effective coefficient. The adder is configured such that the forcing differential control voltage can prevent the adaptive differential control voltage from producing a sign change in the effective coefficient.

Abstract: Tap coefficients for fractionally-spaced equalizers are updated iteratively using error statistics from an input bit stream and an output bit stream, such as from a forward error correction circuit. The process continues until the errors converge to a sufficiently small number. Knowledge of the error patterns are used apriori to adaptively change the tap coefficients in a feedforward filter.

Abstract: A linear interpolator is provided that includes differential pairs of transistors biased such that a first input voltage may be multiplied by a factor r wherein 0?r?1 and such that a second input voltage may be multiplied by the complement factor (1?r). By combining the multiplied input voltages, a linear interpolation is provided based upon the factor r.

Abstract: A digitally controlled transconductance cell includes a differential transistor pair coupled to load elements (either passive or active with resistive or impedance loads) and a variable bias current source, where the transconductance or gain is digitally varied by changing the aspect ratio of the transistors and the bias current.

Abstract: An apparatus and method for adaptively introducing a compensating signal latency related to a signal latency of a data symbol decision circuit. Adaptive timing control circuitry, including an interpolating mixer implemented as a tapped delay line with correlated tap coefficients, introduces a latency adaptively and substantially matching the latency of the data decision circuit for use within an adaptive equalizer, thereby minimizing the mean-squared error of such decision circuit. This adaptive latency is used in generating the feedback error signal which, in turn, can be used by the feedforward equalizer for dynamically adjusting its adaptive filter tap coefficients.

Abstract: Systems and methods provide automatic gain control, such as by employing analog and digital techniques. For example, overall gain may be controlled through coarse and fine control signals provided to gain stages, with the overall gain monitored via a power detector circuit.

Abstract: A linear interpolator is provided that includes differential pairs of transistors biased such that a first input voltage may be multiplied by a factor r wherein 0?r?1 and such that a second input voltage may be multiplied by the complement factor (1?r). By combining the multiplied input voltages, a linear interpolation is provided based upon the factor r.

Abstract: An adaptive coefficient signal generator for use in an adaptive signal equalizer with fractionally-spaced feedback. The signals representing the feedback tap coefficients are generated in conjunction with a timing interpolation parameter such that the fractionally-spaced feedback circuitry dynamically emulates symbol-spaced feedback circuitry.

Abstract: An integrated circuit including a differentially excited symmetric microstrip inductor formed over multiple layers while maintaining both electrical and geometrical symmetry.

Abstract: An apparatus and method for adaptively introducing a compensating signal latency related to a signal latency of a data symbol decision circuit. Adaptive timing control circuitry, including an interpolating mixer implemented as a tapped delay line with correlated tap coefficients, introduces a latency adaptively and substantially matching the latency of the data decision circuit for use within an adaptive equalizer, thereby minimizing the mean-squared error of such decision circuit. This adaptive latency is used in generating the feedback error signal which, in turn, can be used by the feedforward equalizer for dynamically adjusting its adaptive filter tap coefficients.

Abstract: Systems and methods provide analog delay elements, which may be utilized in isolation or in a cascade. For example, a delay element may include a broadband amplifier and a passive, programmable filter, which may provide a desired magnitude and group delay response over a wide frequency range while being tolerant of process variations.

Abstract: Systems and methods provide automatic gain control, such as by employing analog and digital techniques. For example, overall gain may be controlled through coarse and fine control signals provided to gain stages, with the overall gain monitored via a power detector circuit.

Abstract: A linear interpolator is provided that includes differential pairs of transistors biased such that a first input voltage may be multiplied by a factor r wherein 0?r?1 and such that a second input voltage may be multiplied by the complement factor (1-r). By combining the multiplied input voltages, a linear interpolation is provided based upon the factor r.

Abstract: A bandgap reference includes a current source providing a current that is proportional to the sum of a first voltage having a positive-to-absolute-temperature (PTAT) temperature dependency and a second voltage having a complementary-to-absolute-temperature (CTAT) dependency. The bandgap reference further includes a variable resistor comprising a fixed resistor that may be selectively combined with one or more of a plurality of selectable resistors, wherein the first voltage is inversely proportional to the resistance of the variable resistor.

Abstract: A digitally controlled transconductance cell includes a differential transistor pair coupled to load elements (either passive or active with resistive or impedance loads) and a variable bias current source, where the transconductance or gain is digitally varied by changing the aspect ratio of the transistors and the bias current.

Abstract: An inductor for an integrated circuit made of a plurality of stacked, electrically coupled, metal layers. Each metal layer includes an inductor formed of a spiral pattern, which except for the top and bottom inductors, are electrically coupled to the spiral inductor formed on the metal layer above and below with an electrical path or via formed between each metal layer. The top and bottom inductors are electrically coupled to the inductor directly below and above, respectively.

Abstract: An integrated circuit including a differentially excited symmetric microstrip inductor formed over multiple layers while maintaining both electrical and geometrical symmetry.

Abstract: An apparatus and method for adaptively introducing a compensating signal latency related to a signal latency of a data symbol decision circuit. Adaptive timing control circuitry, including an interpolating mixer implemented as a tapped delay line with correlated tap coefficients, introduces a latency adaptively and substantially matching the latency of the data decision circuit for use within an adaptive equalizer, thereby minimizing the mean-squared error of such decision circuit. This adaptive latency is used in generating the feedback error signal which, in turn, can be used by the feedforward equalizer for dynamically adjusting its adaptive filter tap coefficients.