According to one aspect of the invention, there is provided a signal processing method, wherein a frame is generated in which at least one position of occurrence of a transition in a pulse value is determined from an input bitstream. According to another aspect of the invention, there is provided a signal processing method, wherein a frame including at least one pulse having a pulse width not less than a minimum pulse width is generated from an input bitstream.

There is provided a clock and data recovery circuit for a high-speed PAM-4 receiver through statistical learning. A clock and data recovery device according to an embodiment includes: an input unit through which data is inputted; a clock input unit through which a clock is inputted; a sampling unit configured to sample the inputted data by using the inputted clock; a controller configured to combine results of sampling at a plurality of sampling points, to determine a state of the clock based on the combined results, and to generate a control value for controlling the clock; and an adjustment unit configured to adjust the clock applied to the sampling unit, based on the control value generated by the controller. Accordingly, a hardware structure is simplified and energy efficiency is enhanced compared to an exiting oversampling clock and data recovery circuit for a PAM-4 receiver.

A receiver samples an analog, multi-level, pulse-amplitude-modulated signal using a clock-and-data recovery circuit (CDR) that samples the signal against adaptively calibrated symbol-decision thresholds in time with a clock signal that is phased aligned with and locked to the signal. The CDR can erroneously align the clock signal to inter-symbol edges of the signal, a condition called “edge lock,” rather than on the symbols themselves. A transition-type detector senses the edge-lock condition and unlocks the CDR, which can then realign the clock signal, this time on the symbols rather than the inter-symbol edges. The receiver can also respond to the edge-lock condition by kick-starting a shift of symbol-decision threshold that helps the CDR settle more quickly on correct symbol-decision thresholds.

According to one embodiment, a semiconductor integrated circuit includes: a converter configured to convert an analog signal into a digital signal based on a clock signal; a comparator configured to determine first data having data of a first number of bits per symbol and second data having data of a second number of bits, less than the first number, per symbol based on the digital signal; a recovery circuit configured to recover the clock signal; and a control circuit configured to input the digital signal and the first data to the recovery circuit in a case where a condition is not satisfied, and to input the digital signal and the second data to the recovery circuit in a case where the condition is satisfied.

Methods, apparatus, and systems for clock and data recovery in a C-PHY interface are disclosed. A receiving device has a plurality of differential receivers and a recovery circuit. The differential receivers are configured to generate difference signals. Each difference signal is representative of voltage difference between one pair of wires in a three-wire serial bus. The recovery circuit is configured to identify a first difference signal that has the greatest voltage magnitude among the plurality of difference signals in a first unit interval and determine signaling state of the three-wire serial bus for the first unit interval based on identity of the pair of wires corresponding to the first difference signal and polarity of the first difference signal in the first unit interval, and to generate a first edge in a clock signal responsive to a transition in the first difference signal during the first unit interval.

Disclosed clock recovery modules provide improved performance with only limited complexity and power requirements. In one illustrative embodiment, a clock recovery method includes: oversampling a receive signal to obtain mid-symbol interval (MSI) samples and between-symbol interval (BSI) samples; processing at least the MSI samples to obtain symbol decisions; filtering the symbol decisions to obtain BSI targets; determining a timing error based on a difference between the BSI samples and the BSI targets; and deriving from the timing error a clock signal for said oversampling.

A multi-PAM equalizer receives an input signal distorted by inter-symbol interference (ISI) and expressing a series of symbols each representing one of four pulse amplitudes to convey two binary bits of data per symbol. High-order circuitry resolves the most-significant bit (MSB) of each two-bit symbol, whereas low-order circuitry 115 resolves the immediate least-significant bit (LSB). The MSB is used without the LSB for timing recovery and to calculate tap values for both MSB and LSB evaluation.

There is provided a clock and data recovery circuit for a high-speed PAM-4 receiver through statistical learning. A clock and data recovery device according to an embodiment includes: an input unit through which data is inputted; a clock input unit through which a clock is inputted; a sampling unit configured to sample the inputted data by using the inputted clock; a controller configured to combine results of sampling at a plurality of sampling points, to determine a state of the clock based on the combined results, and to generate a control value for controlling the clock; and an adjustment unit configured to adjust the clock applied to the sampling unit, based on the control value generated by the controller. Accordingly, a hardware structure is simplified and energy efficiency is enhanced compared to an exiting oversampling clock and data recovery circuit for a PAM-4 receiver.

A clock adjustment circuit includes a pattern filter circuit, a phase error detector (PED) circuit, and a phase error calculation circuit. The pattern filter circuit selects first predetermined data patterns from a plurality of consecutive data samples under an acquisition mode of the clock adjustment circuit, wherein the plurality of consecutive data samples are derived from an output of a first sampler circuit. The PED circuit detects phase errors according to an output of the pattern filter circuit and error samples derived from an output of a second sampler circuit. The phase error calculation circuit determines timing compensation of a sampling clock according to an output of the PED circuit, wherein the sampling clock is used by the first sampler circuit and the second sampler circuit.

A receiver samples an analog, multi-level, pulse-amplitude-modulated signal using a clock-and-data recovery circuit (CDR) that samples the signal against adaptively calibrated symbol-decision thresholds in time with a clock signal that is phased aligned with and locked to the signal. The CDR can erroneously align the clock signal to inter-symbol edges of the signal, a condition called “edge lock,” rather than on the symbols themselves. A transition-type detector senses the edge-lock condition and unlocks the CDR, which can then realign the clock signal, this time on the symbols rather than the inter-symbol edges. The receiver can also respond to the edge-lock condition by kick-starting a shift of symbol-decision threshold that helps the CDR settle more quickly on correct symbol-decision thresholds.