Digital receivers

A method of processing a received digital signal comprising:

• generating a clock signal for sampling the received signal each bit period;
• continuously adjusting the phase of the clock signal to dynamically maximize the vertical eye opening of the received signal at a sampling time;
• measuring the vertical eye opening of the received signal at the phase of the clock signal;
• making an adjustment to the phase of the clock signal in a direction;
• determining whether the vertical eye opening has increased or decreased;
• and
• if the vertical eye opening has increased, making another adjustment to the phase in a same direction and, if not, making an adjustment to the phase in an opposite direction.

A method of processing a received digital signal comprising:

• generating a first clock signal for sampling the received signal each bit period;
• determining a vertical eye opening including determining a first signal value that a first predetermined proportion of samples are below and a second signal value that a second predetermined proportion of signal values are below and determining the difference between the first and second signal values;
• and
• continuously adjusting the phase of the first clock signal to dynamically maximize the vertical eye opening of the signal at a sampling time.