Signal decimation techniques
First Claim
1. A method for decimating a first periodic signal to generate a second periodic signal, the method comprising:
- calculating a first ratio comprising a ratio of the frequency of the first periodic signal to the frequency of the second periodic signal;
storing an incrementing cycle index;
accumulating the first ratio with a delayed signal once per cycle index;
computing the floor function of the output of the accumulating to generate a configurable integer ratio;
dividing the frequency of the first periodic signal by the configurable integer ratio to generate an intermediate signal; and
delaying the intermediate signal by a configurable delay to generate the second periodic signal.
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Accused Products
Abstract
Techniques for decimating a first periodic signal to generate a second periodic signal. In an exemplary embodiment, the first periodic signal is divided by a configurable integer ratio divider, and the output of the divider is delayed by a configurable fractional delay. The configurable fractional delay may be noise-shaped using, e.g., sigma-delta modulation techniques to spread the quantization noise of the fractional delay over a wide bandwidth. In an exemplary embodiment, the first and second periodic signals may be used to generate the transmit (TX) and receive (RX) local oscillator (LO) signals for a communications transceiver from a single phase-locked loop (PLL) output.
49 Citations
30 Claims
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1. A method for decimating a first periodic signal to generate a second periodic signal, the method comprising:
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calculating a first ratio comprising a ratio of the frequency of the first periodic signal to the frequency of the second periodic signal; storing an incrementing cycle index; accumulating the first ratio with a delayed signal once per cycle index; computing the floor function of the output of the accumulating to generate a configurable integer ratio; dividing the frequency of the first periodic signal by the configurable integer ratio to generate an intermediate signal; and delaying the intermediate signal by a configurable delay to generate the second periodic signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An apparatus configured to store an incrementing cycle index and to calculate a first ratio comprising a ratio of a frequency of a first periodic signal to a frequency of a second periodic signal, the apparatus comprising:
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a clocked summer configured to accumulate the first ratio with a delayed signal once per cycle index; a floor function block configured to compute a floor function of an output of the clocked summer to generate a configurable integer ratio; an integer division block configured to divide the frequency of a first periodic signal by the configurable integer ratio to generate an intermediate signal; and a delay block configured to delay the intermediate signal by a configurable delay to generate the second periodic signal. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A device for wireless communications, the device comprising at least one baseband TX amplifier for amplifying an analog TX signal, an LO signal generator comprising a TX LO signal generator and an RX LO signal generator, an upconverter coupled to the TX LO signal generator and the at least one baseband TX amplifier, a TX filter coupled to the output of the upconverter, a power amplifier (PA) coupled to the TX filter, an RX filter, a low-noise amplifier (LNA) coupled to the RX filter, a downconverter coupled to the RX LO signal generator and the RX filter, and at least one low-pass filter coupled to the output of the downconverter, the LO signal generator comprising:
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an integer division block configured to divide the frequency of a first periodic signal by a configurable integer ratio to generate an intermediate signal; and a delay block configured to delay the intermediate signal by a configurable delay to generate the second periodic signal;
at least one of the TX LO signal generator and the RX LO signal generator configured to buffer the first periodic signal as the LO signal. - View Dependent Claims (28, 29)
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30. A non-transitory computer-readable medium storing code for causing a computer to decimate a first periodic signal to generate a second periodic signal, the code comprising:
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code for causing a computer to calculate a first ratio comprising a ratio of the frequency of the first periodic signal to the frequency of the second periodic signal; code for causing a computer to store an incrementing cycle index; code for causing a computer to accumulate the first ratio with a delayed signal once per cycle index; code for causing a computer to compute the floor function of the output of the accumulating to generate a configurable integer ratio; code for causing a computer to divide the frequency of the first periodic signal by the configurable integer ratio to generate an intermediate signal; and code for causing a computer to delay the intermediate signal by a configurable delay to generate the second periodic signal.
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Specification