Apparatus for skew compensating signals

An apparatus for skew compensating pulse signals, each pulse signal including a sequence of pulses transmitted to separate nodes of a circuit, the apparatus comprising:

• a plurality of delay circuits, each delay circuit producing a separate output signal in response to an applied pulse signal, each delay circuit having first and second control inputs, each output signal comprising pulses delayed from corresponding signal pulses by an adjustable delay time, said delay time comprising a sum of a selected number of unit delays, said number of unit delays being selected by a first control signal applied to said first control input, said unit delay being of duration controlled by a second control signal applied to said second control input;
• means for coupling the output signal produced by each delay circuit to a separate one of said nodes;
• delay setting means for generating a plurality of first control signals, each first control signal being applied to the first control input of a separate one of said delay circuits, each first control signal being set so that pulses of separate output signals arrive at said nodes substantially at the same time when the unit delays of said delay circuits are substantially similar;
• means for generating a periodic reference clock signal having a constant period;
• an oscillator for producing a periodic output signal of period determined in accordance with said second control signal;
• and
• means for producing said second control signal of magnitude determined in accordance with a comparison of the period of said reference clock signal with the period of said periodic output signal, said second control signal being applied in common to the second control input of each of said delay circuits.

An apparatus for providing skew compensated clock signals to separate nodes of a circuit comprising:

• means for generating a master clock signal comprising a sequence of pulses;
• a plurality of delay circuits, each for producing in response to said master clock signal a separate output clock signal and each having first, second and third control inputs, each output clock signal comprising pulses delayed from corresponding master clock signal pulses by an adjustable delay time, said delay time comprising a sum of a selected number of unit delays and an insertion delay, said number of unit delays being selected by a first control signal applied to said first control input, said unit delay being of duration controlled by a second control signal applied to said second control input, and said insertion delay being controlled by a second control signal applied to said third control input;
• means for conducting the output clock signal produced by each delay circuit to a separate one of said nodes;
• delay setting means for generating a plurality of first control signals, each first control signal being applied to the first control input of a separate one of said delay circuits, each first control signal being set so that pulses of separate output clock signals corresponding to the same pulse of the master clock signal arrive at said nodes substantially at the same time when each delay circuit has substantially the same insertion delay and substantially the same unit delay;
• means for generating a periodic reference clock signal having a constant period;
• a first oscillator for producing a first periodic output signal of period determined in accordance with said second control signal;
• means for producing said second control signal of magnitude determined in accordance with a comparison of the period of said reference clock signal with the period of said first periodic output signal;
• a second oscillator for producing a second periodic output signal of period proportional to said insertion delay, the duration of said insertion delay being determined in accordance with said third control signal;
• and
• means for producing said third control signal of magnitude determined in accordance with a difference between the period of said reference clock signal and the period of said second periodic output signal.