Method and apparatus for a digital clock multiplication circuit
First Claim
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1. A method for frequency multiplication of an input signal having a first signal level and a second signal level and a first frequency, comprising:
- producing a first intermediate signal having m oscillations during the first half of a first cycle of said input signal and no oscillations during the second half of said first cycle, including feeding said input signal to an input of a first oscillation circuit;
producing a second intermediate signal having no oscillations during the first half of said first cycle and having n oscillations during a second half cycle of said first cycle, including inverting said input signal to produce an inverted signal and feeding said inverted signal to an input of a second oscillation circuit; and
combining said first and second intermediate signals to produce an output signal having a second frequency that is a multiple of said first frequency, each said oscillation circuit having an operating point which varies depending on the level of the signal at its input, each said oscillation circuit further having a transfer function characterized by having an unstable operating region bounded by a first stable operating region and a second stable operating region so that said circuit produces oscillatory output when said operating point is varied into said unstable region and said circuit has a non-oscillatory output when said operating point is varied into either of said first and second stable regions.
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Abstract
A clock multiplication technique includes driving two oscillatory circuits by an input signal. One of the circuits has an inverted input. The oscillatory circuits are characterized by a transfer function having an unstable region bounded by two stable region. Oscillations produced during operation of each of the circuits in the unstable regions are combined to produce a signal whose frequency is a multiple of the input frequency.
5 Citations
28 Claims
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1. A method for frequency multiplication of an input signal having a first signal level and a second signal level and a first frequency, comprising:
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producing a first intermediate signal having m oscillations during the first half of a first cycle of said input signal and no oscillations during the second half of said first cycle, including feeding said input signal to an input of a first oscillation circuit;
producing a second intermediate signal having no oscillations during the first half of said first cycle and having n oscillations during a second half cycle of said first cycle, including inverting said input signal to produce an inverted signal and feeding said inverted signal to an input of a second oscillation circuit; and
combining said first and second intermediate signals to produce an output signal having a second frequency that is a multiple of said first frequency, each said oscillation circuit having an operating point which varies depending on the level of the signal at its input, each said oscillation circuit further having a transfer function characterized by having an unstable operating region bounded by a first stable operating region and a second stable operating region so that said circuit produces oscillatory output when said operating point is varied into said unstable region and said circuit has a non-oscillatory output when said operating point is varied into either of said first and second stable regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21)
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13. A frequency multiplication circuit comprising:
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a signal input terminal for receiving an input signal having a first frequency, said input signal having a first signal level and a second signal level;
a first oscillation circuit having an input coupled to receive a signal from said signal input terminal, and further having an output;
an inverter circuit having an input coupled to receive a signal from said signal input terminal, and further having an output;
a second oscillation circuit having an input coupled to receive an inverted signal from said output of said inverter circuit, and further having an output; and
a combining circuit having an input coupled to receive signals from said outputs of said oscillation circuits, said combining circuit further having a signal output terminal, each said oscillation circuit configured so that its transfer function has an unstable operating region bounded by a first stable operating region and by a second stable operating region, said transfer function defining a set of operating points, said operating points being dependent on the signal level at said oscillation circuit input, each said oscillation circuit further configured to produce oscillatory output when said operating point is varied into said unstable region, each said oscillation circuit further adapted to produce a non-oscillatory output when said operating point is varied into either of said first and second stable regions.
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22. A digital system comprising:
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first digital circuitry; and
second digital circuitry operatively coupled to said first digital circuitry, said second digital circuitry including a digital clock multiplier, said digital clock multiplier comprising;
a clock input terminal for receiving a clock signal having a first frequency, said clock signal having a first signal level and a second signal level;
a first oscillation circuit having an input coupled to receive a signal from said clock input terminal, and further having an output;
an inverter circuit having an input coupled to receive a signal from said clock input terminal, and further having an output;
a second oscillation circuit having an input coupled to receive an inverted signal from said output of said inverter circuit, and further having an output; and
a combining circuit having an input coupled to receive signals from said outputs of said oscillation circuits, said combining circuit further having a clock output terminal, each said oscillation circuit having a transfer function, said transfer function having an unstable operating region bounded by a first stable operating region and by a second stable operating region, said transfer function defining a set of operating points of each said oscillation circuit, each said oscillation circuit adapted to produce oscillatory output when said operating point is varied into said unstable region, each said oscillation circuit further adapted to produce a non-oscillatory output when said operating point is varied into either of said first and second stable regions. - View Dependent Claims (23, 24, 26, 27, 28)
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25. A method for frequency multiplication of an input signal by a factor of (m+n), comprising:
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producing a first signal having m oscillations during the first half of a first cycle of said input signal and no oscillations during the second half of said first cycle;
producing a second signal having no oscillations during the first half of said first cycle and having n oscillations during a second half cycle of said first cycle; and
combining said first and second signals to produce a third signal that has a frequency of (m+n) times the frequency of said input signal.
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Specification