Abstract: A tunable bandpass filter to provide a filtered differential clock signal in response to an input differential clock signal, where an embodiment comprises a transistor pair loaded by tunable loads, and a feedback circuit to tune the tunable loads. In some embodiments, the feedback circuit tunes the loads to maximize a small-signal differential gain. In other embodiments, the feedback circuit tunes the loads to minimize a metric indicative of jitter in the filtered differential clock signal. Other embodiments are described and claimed.

Abstract: In some embodiments disclosed herein, equalizers in a receiver are adapted during normal operation, as they extract bit data from a received bit stream, to account for channel and/or circuit fluctuations.

Abstract: An apparatus is provided that includes an injection locked oscillator and a transmitting device. The injection locked oscillator to receive a first clock signal and to provide a second clock signal by skewing the first clock signal. The transmitting device to receive an input signal and to receive the second clock signal as a clocking signal, the transmitting device to transmit an output signal based on the received clocking signal.

Abstract: A global clock recovery circuit and port circuit determine and combine static phase adjustment information and dynamic phase adjustment information for multiple data signals. Static phase adjustment information is determined for each of the multiple data signals, and dynamic phase adjustment information is determined in common for the multiple data signals.

Abstract: In general, in one aspect, the disclosure describes an apparatus that includes an inductive capacitive voltage controlled oscillator (LC VCO) to generate an output clock. A voltage to current converter is used to receive a forwarded clock and to inject the forwarded clock to the LC VCO. The output clock is a deskewed version of the forwarded clock.

Abstract: A system and method for encoding and receiving data is provided. The data is encoded as a pulse amplitude modulated signal such that the amplitude signals do not transition from the highest signal level to the lowest signal level and do not transition from the lowest signal level to the highest signal level. The encoding and decoding is performed in some embodiments via a lookup table, and in further embodiments is designed to minimize the step between sequential pulse amplitude modulated symbols.

Abstract: An integrated circuit compensates for power supply voltage dependent delay using a clock circuit that is responsive to a power supply voltage measuring circuit. The clock circuit modifies a phase relationship based on a measured power supply voltage value.

Abstract: A system and method for encoding and receiving data is provided. The data is encoded as a pulse amplitude modulated signal such that the amplitude signals do not transition from the highest signal level to the lowest signal level and do not transition from the lowest signal level to the highest signal level. The encoding and decoding is performed in some embodiments via a lookup table, and in further embodiments is designed to minimize the step between sequential pulse amplitude modulated symbols.

Abstract: A clock signal is deskewed relative to a data signal by sweeping a sampling point in time and sweeping an amplitude offset. Bit error measurements are made at each sampling point in time and compared. Bit error measurements may be made by comparing received data to predetermined data values. The predetermined data values may be sourced from a linear feedback shift register.

Abstract: According to some embodiments, a circuit includes a current mirror to receive a multi-level current signal, and to generate a plurality of current signals substantially identical to the multi-level current signal. Such a circuit may also include a plurality of current comparison circuits, each of the plurality of current comparison circuits to receive a respective one of the plurality of generated current signals, to receive a respective reference current signal, and to generate a signal indicating a relationship between the received respective one of the plurality of generated current signals and the respective reference current signal.

Abstract: An adaptive equalizer finite impulse response (FIR) filter for high-speed communication channels with modest complexity, where the filter is iteratively updated during a training sequence by a circuit performing the update: h(t+1)= h(t)+?[sgn{d(t)}?sgn{z(t)?Kd(t)}]sgn{ x(t)}, where h(t) is the filter vector representing the filter taps of the FIR filter, x(t) is the data vector representing present and past samples of the received data x(t), d(t) is the desired data used for training, z(t) is the output of the FIR filter, ? determines the memory or window size of the adaptation, and K is a scale factor taking into account practical limitations of the communication channel, receiver, and equalizer. Furthermore, a procedure and circuit structure is provided for calibrating the scale factor K.

Abstract: A current summing FIR filter can be implemented with multiple differential input stages and variable tail currents. The variable tail currents can be used to appropriately weight the present and previous digital input signals. The weighted outputs of the differential transistor pairs can be summed to provide a filtered output signal. The tail currents can be advantageously varied with variable current sources or by adjustment of the relative widths of the differential transistor pairs. In other embodiments, additional differential pairs can be added to adjust for systematic offset voltages caused by process-induced variations in the structure of circuit devices or to induce a desired offset.

Abstract: An adaptive equalizer finite impulse response (FIR) filter for high-speed communication channels with modest complexity, where the filter is iteratively updated during a training sequence by a circuit performing the update: h(t+1)= h(t)+?[sgn{d(t)}?sgn{z(t)?Kd(t)}]sgn{ x(t)}, where h(t) is the filter vector representing the filter taps of the FIR filter, x(t) is the data vector representing present and past samples of the received data x(t), d(t) is the desired data used for training, z(t) is the output of the FIR filter, ? determines the memory or window size of the adaptation, and K is a scale factor taking into account practical limitations of the communication channel, receiver, and equalizer. Furthermore, a procedure and circuit structure is provided for calibrating the scale factor K.

Abstract: In some embodiments, an adaptive filter employs two adaptation modes, where during one adaptation mode the adaptive filter is updated only when the received training sample is a first binary value and during the other adaptation mode the adaptive filter is updated only when the received sample is a second binary value. Each adaptation mode provides a set of filter weights, and these two sets of filter weights are averaged to provide an adapted set of filter weights. The use of two adaptation mode allows for a clock boundary in which the digital portion of the filter operates at a lower clock rate than the analog portion. In other embodiments, a filter architecture is described for providing the algebraic signs of the received data samples, important for sign-sign least means square filtering algorithms. In other embodiments, a filter architecture is described in which efficient use is made of voltage-to-current converters so as to achieve a high throughput rate during filtering.

Abstract: An integrated circuit is provided that includes a first port to receive a first signal from a first channel and a first device coupled to the first port to modify a channel response of the first signal received from the first channel. A waveform capture device may be coupled to the first device to capture a waveform of a signal modified by the first device.

Abstract: An electrostatic discharge protection unit includes a channel, a passive filter, and an electrostatic discharge protection circuit. The passive filter and the electrostatic discharge protection circuit are formed on a substrate. The electrostatic discharge protection circuit couples the channel to the passive filter. A method includes, for a channel having a bandwidth determining the bandwidth, and generating a transfer function for a passive filter which when combined in series an electrostatic discharge protection circuit and the channel yields a combination transfer function which has a combination bandwidth that is greater than the channel transfer function bandwidth.

Abstract: A digital to analog converter (DAC) circuit operates least significant bit (LSB) first.

Abstract: A receiver is calibrated using a transmitter that can output a plurality of substantially constant amplitude signals.

Abstract: A clock recovery circuit includes a delay locked loop, and a clock phase interpolator circuit. The delay locked loop provides multiple phases of an input clock signal to the interpolator circuit, which interpolates between two of the clock phases to provide a clock signal at a desired phase. The clock phase interpolator circuit includes selectable differential transistor pairs coupled to variable current sources. Different differential transistor pairs are driven by clock signals of different phases provided by the delay locked loop circuit. Two differential transistor pairs are selected, and currents provided to the selected differential transistor pairs are adjusted to provide an output clock of the desired phase.

Abstract: A device includes a bus, a first transmitter connected to the bus and configured to transmit a first signal over the bus in a first frequency band, a second transmitter connected to the bus and configured to transmit a second signal over the bus in a second frequency band at the same time that the first transmitter is transmitting the first signal, a first receiver connected to the bus and configured to receive the first signal transmitted over the bus in the first frequency band, and a second receiver connected to the bus and configured to receive the second signal transmitted over the bus in the second frequency band. The first frequency band and the second frequency band occupy different portions of the frequency spectrum.