Phase locked loop for high speed data capture of a serial data stream
First Claim
1. A phase locked loop for locking on to a phase and frequency of a serial data stream, comprising:
- a data input for receiving the serial data stream;
a multiple-bit latch having a plurality of designated data and boundary-detect latch elements, with each latch element comprising a latch input coupled to the data input, a sample clock input, and a latch output;
a multiple-stage voltage controlled oscillator having a voltage control input, a plurality of sample clock outputs, and an adjustable delay between each sample clock output, wherein each sample clock output is coupled to a corresponding sample clock input;
a phase detection circuit having phase detect inputs coupled to the latch outputs and having a phase control output; and
a feedback circuit coupled between the phase control output and the voltage control input.
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Accused Products
Abstract
A phase locked loop locks on to the phase of a high speed serial data stream. The phase locked loop includes a multiple bit latch, a multiple-stage voltage controlled oscillator, a phase detection circuit and a feedback circuit. The multiple-bit latch has a plurality of data latch elements and boundary-detect latch elements. Each latch element includes a latch input for receiving the serial data stream, a sample clock input and a latch output. The multiple-stage voltage controlled oscillator has a voltage control input, a plurality of sample clock outputs and an adjustable delay between each sample clock output. Each sample clock output is coupled to a corresponding sample clock input. The phase detection circuit is coupled to the latch outputs of the data and boundary-detect latch elements and has a phase control output. A feedback circuit is coupled between the phase control output and the voltage control input.
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Citations
19 Claims
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1. A phase locked loop for locking on to a phase and frequency of a serial data stream, comprising:
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a data input for receiving the serial data stream; a multiple-bit latch having a plurality of designated data and boundary-detect latch elements, with each latch element comprising a latch input coupled to the data input, a sample clock input, and a latch output; a multiple-stage voltage controlled oscillator having a voltage control input, a plurality of sample clock outputs, and an adjustable delay between each sample clock output, wherein each sample clock output is coupled to a corresponding sample clock input; a phase detection circuit having phase detect inputs coupled to the latch outputs and having a phase control output; and a feedback circuit coupled between the phase control output and the voltage control input. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A system for data capture and clock recovery of a serial data stream, comprising:
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a data input for receiving the serial data stream; a multiple-bit latch having a plurality of designated data and boundary-detect latch elements, with each latch element comprising a latch input coupled to the data input, a sample clock input, and a latch output; a multiple-stage voltage controlled oscillator having a voltage control input, a plurality of sample clock outputs, and an adjustable delay between each sample clock output, wherein each sample clock output is coupled to a corresponding sample clock input; a phase detection circuit having phase detect inputs coupled to the latch outputs and having a phase control output; a phase locked feedback loop coupled between the phase control output and the voltage control input; and a data recovery storage element having a plurality of data recovery inputs which are coupled to respective latch outputs of the designated data latch elements and having a recovery clock input which is coupled to one of the plurality of sample clock outputs.
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16. A method of locking onto a phase and frequency of a serial input signal, comprising:
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applying the serial input signal to a multiple-bit latch comprising a boundary detect latch element, a previous in time data latch element and a subsequent in time data latch element, wherein each latch element comprises a latch output; generating a first sample clock, a second sample clock which is delayed from the first sample clock by a delay, and a third sample clock which is delayed from the second sample clock by the delay; operating the previous data latch element with the first sample clock, the boundary-detect latch element with the second sample clock and the subsequent data latch element with the third sample clock; decreasing the delay if the latch outputs of the previous in time data latch element and the boundary-detect latch element have different logic states; and increasing the delay if the latch outputs of the boundary-detect latch element and the subsequent in time data latch element have different logic states. - View Dependent Claims (17, 18, 19)
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Specification