Non-linear decision feedback phase locked loop filter

A receiver for receiving signals from a transmission channel, comprising:

• slicer circuitry adapted to receive a signal transmitted through the transmission channel and determine amplitude levels for symbols in the received signal;
• and
• phase locked loop circuitry adapted to:
• provide a timing signal for use by the slicer circuitry in determining the amplitude levels for symbols;
• detect a phase of the received signal using signal transitions within the received signal;
• determine whether the signal transitions are good signal transitions for detecting the phase of the received signal;
• and
• adjust a phase of the timing signal using the good signal transitions.

A receiver for receiving signals transmitted through a transmission channel, comprising:

• slicer circuitry adapted to determine amplitude levels for symbols within a received signal, the slicer circuitry including a slicer output for providing the amplitude levels for the symbols;
• and
• phase locked loop circuitry, including:
• a voltage controlled oscillator adapted to provide a timing signal for the slicer circuitry to determine the amplitude levels;
• a phase detector adapted to detect signal transitions and provide a phase signal that represents a signal phase for the received signal;
• a decision logic module connected to the slicer output and adapted to provide a decision feedback output that indicates whether the amplitude levels represent good signal transitions for detecting the phase of the received signal;
• and
• a decision feedback equalizer adapted to receive the decision feedback output, and pass the phase signal for a good signal transition such that only good signal transitions are used by the voltage controlled oscillator in adjusting the timing signal for the slicer circuitry.

A method for selecting desirable signal transitions for use in correcting a timing signal for a receiver, comprising:

• receiving a first symbol pulse and a second symbol pulse from a transmission channel, wherein the first symbol pulse and the second symbol pulse have amplitude levels, and wherein a signal transition occurs between the first symbol pulse and the second symbol pulse;
• detecting a signal phase for one of the first symbol pulse and the second symbol pulse using the signal transition and the timing signal for the receiver;
• sampling a signal that represents the signal phase using the timing signal for the receiver;
• determining amplitude levels for the first symbol pulse and the second symbol pulse;
• determining whether the signal transition between the amplitude levels for the first and second symbol pulses is a good transition for determining the signal phase and correcting the timing signal for the receiver;
• and
• upon determining that the signal transition is a good transition, passing the sampled signal that represents the signal phase to a loop filter and a voltage controlled oscillator for use in adjusting the timing signal for the receiver.