Embodiments of this application disclose example phase detection methods, phase detection circuits, and clock recovery apparatuses. One example method includes receiving a first signal and deciding a (2M−1) level of the first signal to obtain a decision result, where the first signal is a (2M−1)-level signal, and M is a positive integer. A response amplitude parameter of a transmission channel can then be obtained. Clock phase information in the first signal can then be extracted based on the first signal, the decision result, and the response amplitude parameter. Output clock phase information can then be determined based on at least three decision results and at least three pieces of clock phase information in at least three symbol periods.

An FPGA based system for decoding PAM-3 signals is disclosed, wherein the system comprises a directional coupler for separating 100BASE-T1 and 1000BASE-T1 master and slave signals, DVGAs for amplifying the master and slave signals, ADCs for sampling the amplified signals, and a FPGA module, wherein the FPGA module is configured for decoding the PAM-3 symbols, in real-time, from oversampled ADCs data using fully pipelined Register Transfer Level (RTL) architecture.

In one embodiment, a local clock is synchronized to a master clock using a Kalman filter to determine state variables using a state transition matrix that includes at least one coefficient that is associated with a digital-to-analog converter (DAC), where the state variables include a unit step variable indicative of a unit step for the system. The local clock is controlled based on the state variables determined using the Kalman filter. The unit step is indicative of an amount by which the frequency of the local clock signal changes in response to a change in the digital input of the DAC.

A receiver device implements enhanced data reception with edge-based clock and data recovery such as with a flash analog-to-digital converter architecture. In an example embodiment, the device implements a first phase adjustment control loop, with for example, a bang-bang phase detector, that detects data transitions for adjusting sampling at an optimal edge time with an edge sampler by adjusting a phase of an edge clock of the sampler. This loop may further adjust sampling in received data intervals for optimal data reception by adjusting the phase of a data clock of a data sampler such a flash ADC. The device may also implement a second phase adjustment control loop with, for example, a baud-rate phase detector, that detects data intervals for further adjusting sampling at an optimal data time with the data sampler.

A method for recovering a clock signal from a data signal by using a clock recovery module is described. Edge timings of the data signal are accumulated. The edge timings accumulated are transformed into one reference bit period. A time offset for the reference bit period is determined. A reference clock signal is determined based on the time offset. The number of bits within a system clock of the clock recovery module is determined. The clock signal is recovered based on the reference clock signal and the number of bits. Further, a clock recovery module as well as a computer program are described.

An example apparatus includes: a feed forward equalizer (FFE) with a FFE output, adder circuitry with a first adder input, a second adder input, and a first adder output, the first adder input coupled to the FFE output, a multiplexer (MUX) with a first MUX input, a second MUX input, and a MUX output, the first MUX input coupled to the first adder output, the second MUX input coupled to the FFE output, a decision feedback equalizer (DFE) with a DFE output coupled to the second adder input, and a timing error detector (TED) with a first TED input coupled to the MUX output.

An FPGA based system for decoding PAM-3 signals is disclosed, wherein the system comprises a directional coupler for separating 100BASE-T1 and 1000BASE-T1 master and slave signals, DVGAs for amplifying the master and slave signals, ADCs for sampling the amplified signals, and a FPGA module, wherein the FPGA module is configured for decoding the PAM-3 symbols, in real-time, from oversampled ADCs data using fully pipelined Register Transfer Level (RTL) architecture.

A clock data recovery (CDR) mechanism qualifies symbols received from the data detector prior to using those symbols to compute a timing gradient. The disclosed CDR mechanism analyzes one or more recently received symbols to determine whether the current symbol should be used in computing the time gradient. When configured with a Mueller-Muller phase detector, the timing gradient for the received signal is set to zero if the current symbol is a −2 or a +2 and the previous symbol is non-zero. Otherwise, the Mueller-Muller timing gradient is evaluated in the traditional manner. When configured with a minimum mean-squared error phase detector, the timing gradient for the received signal is set to zero if the previous symbol is non-zero. Otherwise, the minimum mean-squared error timing gradient is evaluated in the traditional manner.

A receiving apparatus includes a first sample circuit configured to extract first binary data based on a first voltage and a clock timing of a received signal, a second sample circuit configured to extract second binary data based on an adjustable second voltage and a clock timing of the received signal, and a waveform processor configured to acquire a plurality of the second binary data from the second sample circuit using a pattern, the pattern corresponding to the first binary data extracted by the first sample circuit with consecutive sampling timings, determine an appearance frequency of the received signal based on the plurality of second binary data and the first binary data, and generate waveform information of the received signal according to the determined appearance frequency.

A clock data recovery circuit includes a circuit that receives a data signal for which each of a plurality of potential levels is associated with a value of 2 bits or more, based on a result of a first comparison that compares the 3 or more first thresholds with the data signal at timing synchronized with a clock signal; a circuit that outputs a result of a second comparison that compares the data signal with a second threshold at the timing; a circuit that generates a phase difference signal indicating whether to advance or delay a phase of the clock signal, based on the result of the determination and the result of the second comparison; a filter that generates a phase adjusted value indicating an adjustment amount of the phase, based on the phase difference signal; and a circuit that adjusts the phase based on the phase adjusted value.