Phase-based receiver with multiple sampling frequencies
First Claim
1. A receiver for processing an input signal having a carrier frequency, the input signal having phase information, the receiver comprising:
- (a) a first clock generator adapted to generate a first clock independent of the carrier frequency of the input signal, wherein the first clock has a first clock frequency;
(b) a second clock generator adapted to generate a second clock independent of the carrier frequency of the input signal, wherein the second clock has a second clock frequency different from the first clock frequency;
(c) a sampler adapted to sample the input signal exclusively using a selected sampling clock having a selected sampling frequency; and
(d) a switch adapted to select one of the first and second clocks as the selected sampling clock for the input signal, wherein the selection of the selected sampling clock is dependent upon the carrier frequency of the input signal, wherein the clock frequency of the selected sampling clock is not harmonically related to the carrier frequency of the input signal.
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Accused Products
Abstract
A receiver for input signals generated using a phase-based modulation scheme such as bipolar-phase shift-keying (BPSK) modulation or quadrature-phase shift-keying (QPSK) modulation. The receiver can sample the input signal using one of at least two different sampling frequencies that are selected such that at least one of the sampling frequencies is not harmonically related to the carrier frequency of the input signal by a ratio of small numbers. In this way, the receiver can avoid interference patterns that can result when the sampling frequency and the carrier frequency are harmonically related. In one embodiment, the receivers are hard-limiting receivers that are suitable for use in the remote nodes of fiber-to-the-curb (FTTC) communication systems, where low-power receivers are desirable.
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Citations
17 Claims
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1. A receiver for processing an input signal having a carrier frequency, the input signal having phase information, the receiver comprising:
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(a) a first clock generator adapted to generate a first clock independent of the carrier frequency of the input signal, wherein the first clock has a first clock frequency; (b) a second clock generator adapted to generate a second clock independent of the carrier frequency of the input signal, wherein the second clock has a second clock frequency different from the first clock frequency; (c) a sampler adapted to sample the input signal exclusively using a selected sampling clock having a selected sampling frequency; and (d) a switch adapted to select one of the first and second clocks as the selected sampling clock for the input signal, wherein the selection of the selected sampling clock is dependent upon the carrier frequency of the input signal, wherein the clock frequency of the selected sampling clock is not harmonically related to the carrier frequency of the input signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for processing an input signal having a carrier frequency, the input signal having phase information, comprising the steps of:
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(a) generating a first clock independent of the carrier frequency of the input signal, wherein the first clock has a first clock frequency; (b) generating a second clock independent of the carrier frequency of the input signal, wherein the second clock has a second clock frequency different from the first clock frequency; (c) selecting one of the first and second clocks as a selected sampling clock, wherein the selection is dependent upon the carrier frequency of the input signal, wherein the clock frequency of the select sampling clock is not harmonically related to the carrier frequency of the input signal; (d) sampling the input signal exclusively using the selected sampling clock. - View Dependent Claims (14, 15, 16, 17)
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Specification