US 2004/0111650 A1 · Apparatus for delay calibration of a forward clock

Abstract

An apparatus for automatic delay calibration of a forward clock. According to the invention, the apparatus includes control logic to receive a normal clock, a lead clock and a lag clock. The control logic therefore generates a delay control signal based on a timing relationship among the normal, the lead and the lag clocks. The apparatus also includes a delay calibrator to receive a reference clock having the same frequency as the forward clock. The delay calibrator generates the lead, the phase lag and the normal clocks from the reference clock and provides them as feedback to the control logic. According to the delay control signal, the delay calibrator can adjust the lead and the lag clocks. Once the timing relationship meets a predetermined condition, the delay control signal is provided to calibrate a delay for the forward clock.

Claims13

Dependent claims

An apparatus for automatic delay calibration of a forward clock, comprising:

control logic for receiving a normal clock, a lead clock and a lag clock, and generating a delay control signal based on a timing relationship among the normal clock, the lead clock and the lag clock;
and
a delay calibrator for receiving a reference clock having the same frequency as the forward clock to provide the normal, the lead and the lag clocks as feedback to the control logic, and adjusting the lead and the lag clocks in accordance with the delay control signal;
wherein the delay control signal is provided to perform a delay calibration for the forward clock once the timing relationship has been adjusted to meet a predetermined condition.

1 more element

An apparatus for automatic delay calibration of a forward clock, comprising:

control logic for receiving a normal clock, a lead clock and a lag clock, and generating a delay control signal based on a state transition table having a set of present states, a set of prior states, a set of prior actions and a set of next actions, wherein each of the present states is defined by a currently received timing relationship among the normal, the lead and the lag clocks, each of the prior states is defined by a previously received timing relationship among the normal, the lead and the lag clocks, and wherein each of the prior actions is indicative of a prior adjustment for the delay control signal, and each of the next actions is indicative of a next adjustment for the delay control signal;
and
a delay calibrator coupled to the control logic, for receiving a reference clock having the same frequency as the forward clock to provide the normal, the lead and the lag clocks as feedback to the control logic, and adjusting the lead and the lag clocks in accordance with the delay control signal.

Dependencies are inferred from the claim text.

Apparatus for delay calibration of a forward clock

Life of this patent

Apparatus for delay calibration of a forward clock

Life of this patent

Abstract

Claims13