The present subject matter relates to methods, systems, circuitry, equipment and devices providing for the automatic provisioning of clock data recovery (CDR) circuitry to automatically align, tune and lock the CDR circuitry to a communication signal. The methods, systems, circuitry, equipment and devices comprise a first CDR circuitry and a second CDR circuitry, and a first connection having two paths and a second connection having two paths. The CDR circuitry is automatically aligned kind locked a communication signal bit rate or wavelength or both. Automatic alignment is achieved by progressing through a communication services list until a communication signal bit rate or wavelength is aligned.

A digital-to-analog conversion circuit includes a first digital-to-analog converter (DAC) and a second DAC. The first DAC includes a first current generation circuit (CGC) and a first current-to-voltage converter. The first CGC generates a first current based on a first digital code received through a first terminal to provide the first current to an output node. The second DAC includes a second CGC and a second current-to-voltage converter. The second CGC generates a second current based on a second digital code received through a second input terminal to provide the second current to the output node. The first current-to-voltage converter and the second current-to-voltage converter convert a sum of the first current and the second current to a an analog voltage corresponding to a sum of the first digital code and the second digital code, and output the analog voltage at the output node.

Methods and apparatus for quickly changing line rates in PCIe analyzers without resetting the receivers. One example circuit for multi-rate reception generally includes: a receiver having a data input, a data output, and a clock input configured to receive a clock signal from a clock generator, the receiver being configured to switch between receiving data at a first data rate and at least one second data rate and to sample data according to the first data rate, wherein the first data rate is higher than the at least one second data rate; a phase detector having an input coupled to the data output of the receiver; and a filter having an input coupled to an output of the phase detector and having an output configured to effectively control a phase of the sampling by the receiver when the data is at the at least one second data rate.

An apparatus has a plurality of multi-level comparison circuits, each coupled to a pair of wires in a three-wire communication link, a plurality of first-level clock recovery circuits and a second-level clock recovery circuit. Each multi-level comparison circuit provides a multibit signal as an output. Each first-level clock recovery circuit includes a plurality of first-level flipflops clocked by transitions in a multibit signal received from one multi-level comparison circuit of the plurality of multi-level comparison circuits, and a first delay circuit that delays an output of the each first-level clock recovery circuit to provide a first reset signal that resets the each first-level clock recovery circuit. The second-level clock recovery circuit includes a second-level flipflop clocked by transitions in the outputs of the plurality of first-level clock recovery circuits, and a second delay circuit that delays an output of the second-level clock recovery circuit to provide a second reset signal to the second-level flipflop.

A clock data recovery circuit includes the following elements: a phase detector for outputting a phase adjustment signal by comparing a clock signal of a first node and an input signal; a charge pump for adjusting a charge amount of a second node according to the phase adjustment signal; a first switch including one end coupled to the second node and including another end coupled to a third node; a second switch including one end which receives a bias voltage and including another end coupled to the third node; a capacitor including a first electrode coupled to the third node; third switches; and voltage control oscillators including control terminals coupled to the third node and including output terminals coupled to the first node through the third switches.

A clock and data recovery circuit includes a voltage controlled oscillator, a frequency detector and a control circuit. The voltage controlled oscillator is configured to generate a clock signal according to a voltage signal. The frequency detector is configured to detect whether increasing a frequency of the clock signal is required according to a plurality of sampling results of the input data signal and accordingly generate a first up control signal. The control circuit is coupled to the voltage controlled oscillator and the frequency detector and configured to adjust the voltage signal according to the first up control signal. The clock and data recovery circuit operates in a data recovery mode after detecting that the frequency of the clock signal is locked, and the frequency detector is configured to detect whether increasing the frequency of the clock signal is required in the data recovery mode.

Disclosed is a card clock recovery system for use in an NFC card transceiver couplable to an NFC reader. The card clock recovery system has: a phase lock loop having: a phase/frequency detector, which is configured to receive a reference signal provided at an RX port of a matching network during a receiving mode of the NFC transceiver or to receive a reference signal provided at the RX port of the matching network during a transmission mode of the NFC transceiver, to receive a loop feedback signal, and to provide a phase error signal that represents a phase difference between the reference signal and the loop feedback signal; a loop filter configured to receive a corrected phase error signal that is derived from the phase error signal, and to provide a filtered corrected phase error signal; a controllable oscillator, which is configured to receive the filtered corrected phase error signal and to provide a controlled frequency output signal, which is provided as the card clock generation control signal to a card clock generation unit of an NFC card transceiver, and as the loop feedback signal, via the loop feedback line, to the phase/frequency detector. The card clock recovery system further has a phase offset correction unit, which is configured to receive the phase error signal provided by the phase/frequency detector and to provide the corrected phase error signal to the loop filter, and which has a phase error sampling unit, a phase offset computation unit, and a phase subtractor unit.

The present invention discloses a transceiver apparatus having phase-tracking mechanism. A phase detection circuit of a receiver circuit performs sampling and phase detection on an input data signal according to a sampling clock signal to generate a phase detection result. A proportional gain circuit of the receiver circuit applies a proportional gain operation on the phase detection result to generate a phase adjusting signal. A CDR circuit of the receiver circuit receives a source clock signal to generate the sampling clock signal and performs phase-adjusting according to the phase adjusting signal. The integral gain circuit apples an integral gain operation on the phase detection result to generate a frequency adjusting signal. The source clock generating circuit receives a reference clock signal to generate the source clock signal and perform frequency-adjusting according to the frequency adjusting signal. The transmitter circuit performs signal transmission according to the source clock signal.

A PAM-4 receiver with jitter compensation clock and data recovery is provided. The receiver includes a first-order delay-locked loop (DLL) which employs a bang-bang phase detector (BBPD) and a voltage-controlled delay line (VCDL) circuit supporting 40 MHz jitter tracking bandwidth and static phase skew elimination. A second-order wideband phase-locked loop (WBPLL) using the ¼-rate reference clock provides multi-phase clock generation with low input-to-output latency. To suppress the consequent jitter transfer, a jitter compensation circuit (JCC) acquires the jitter transfer amplitude and frequency information by detecting the DLL loop filter voltage (VLF(s)) signal, and generates an inverted loop filter voltage signal, denoted as VLF.sub.INV(s). The VLF.sub.INV(S) modulates a group of complementary VCDLs (C-VCDLs) to attenuate the jitter transfer on both recovered clock and data. With the provided receiver, a jitter compensation ratio up to 60% can be supported from DC to 4 MHz, with a −3-dB corner frequency of 40 MHz.

A memory controller includes a clock signal generator generating a clock signal; a first data receiving circuit receiving a serial signal having a plurality of logic values from a memory, using the serial signal to compensate for a phase error of the clock signal, and generating a phase-compensated clock signal as a first clock signal; and at least one second data receiving circuit receiving data from the memory, receiving the first clock signal from the first data receiving circuit, and using the first clock signal to recover the data.