Reference-less frequency detector
AssigneeBroadcom Corporation
InventorsMahyar Kargar, Siavash Fallahi, Namik Kocaman, Mehdi Khanpour, Afshin Momtaz
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Abstract
Embodiments provide a reference-less frequency detector that overcomes the “dead zone” problem of conventional circuits. In particular, the frequency detector is able to accurately resolve the polarity of the frequency difference between the VCO clock signal and the data signal, irrespective of the magnitude of the frequency difference and the presence of VCO clock jitter and/or ISI on the data signal.
Claims20
A method for determining a polarity of a frequency difference between a data signal and a clock signal, comprising:
- sampling the clock signal according to an in-phase component and a quadrature phase component of the data signal, respectively, to generate a first signal and a second signal;
- sampling the second signal according to the first signal to generate a third signal;
- sampling the first signal according to the second signal to generate a fourth signal;
- and
- sampling the third signal according to the fourth signal to generate a fifth signal, wherein the fifth signal provides the polarity of the frequency difference between the data signal and the clock signal.
A method for calibrating a Voltage Controlled Oscillator (VCO), comprising:
- sampling a VCO clock according to a first component and a second component of a data signal, respectively, to generate a first signal and a second signal;
- sampling the second signal according to the first signal to generate a third signal;
- sampling the first signal according to the second signal to generate a fourth signal;
- sampling the third signal according to the fourth signal to generate a fifth signal;
- and
- controlling the VCO according to the fifth signal when a frequency difference between the data signal and the VCO clock is within a defined frequency difference range.
A method for calibrating a clock signal, comprising:
- sampling the clock signal according to an in-phase component and a quadrature phase component of a data signal, respectively, to generate a first signal and a second signal;
- sampling the second signal according to the first signal to generate a third signal;
- sampling the first signal according to the second signal to generate a fourth signal;
- and
- sampling the third signal according to the fourth signal to generate a fifth signal.
Dependencies are inferred from the claim text.