Method and apparatus for detecting reception of a tone signal
First Claim
1. A method for detecting reception of a tone signal, the method comprising the steps of:
- a) receiving an in-phase signal component and a quadrature signal component;
b) sampling the in-phase signal component with a first sampler to produce a plurality of sampled in-phase signal components;
c) sampling the quadrature signal component with a second sampler to produce a plurality of sampled quadrature signal components;
d) shifting the plurality of sampled quadrature signal components by a predetermined phase angle to produce a plurality of phase shifted quadrature components;
e) comparing a set of phase shifted quadrature components with a set of sampled in-phase signal components; and
f) when each phase shifted quadrature component of the set of phase shifted quadrature components substantially matches each corresponding sampled in-phase signal component of the set of the sampled in-phase signal components, indicating that the tone signal is being received.
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Accused Products
Abstract
Tone detection may be accomplished by receiving an in-phase signal component 203 and a quadrature signal component 204. These components are then sampled to produce a plurality of sampled in-phase signal components 207 and a plurality of sampled quadrature signal components 208. The sampled in-phase signal components 207, or the sampled quadrature signal components 208, are then shifted by a pre-determined phase angle to produce a plurality of shifted components. Having shifted these signals, the shifted signals, or at least a set of them, are compared with the opposite non-shifted sampled signals, or a set thereof. When each of the shifted signal components substantially match the opposite non-shifted signal components, a tone signal is being received.
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Citations
16 Claims
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1. A method for detecting reception of a tone signal, the method comprising the steps of:
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a) receiving an in-phase signal component and a quadrature signal component; b) sampling the in-phase signal component with a first sampler to produce a plurality of sampled in-phase signal components; c) sampling the quadrature signal component with a second sampler to produce a plurality of sampled quadrature signal components; d) shifting the plurality of sampled quadrature signal components by a predetermined phase angle to produce a plurality of phase shifted quadrature components; e) comparing a set of phase shifted quadrature components with a set of sampled in-phase signal components; and f) when each phase shifted quadrature component of the set of phase shifted quadrature components substantially matches each corresponding sampled in-phase signal component of the set of the sampled in-phase signal components, indicating that the tone signal is being received. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for detecting reception of a tone signal, the method comprising the steps of:
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a) receiving an in-phase signal component and a quadrature signal component; b) sampling the in-phase signal component with a first sampler to produce a plurality of sampled in-phase signal components; c) sampling the quadrature signal component with a second sampler to produce a plurality of sampled quadrature signal components; d) shifting the plurality of sampled in-phase signal components by a predetermined phase angle to produce a plurality of phase shifted in-phase components; e) comparing a set of phase shifted in-phase components with a set of sampled quadrature signal components; and f) when each phase shifted in-phase component of the set of phase shifted in-phase components substantially matches each corresponding sampled quadrature signal component of the set of the sampled quadrature signal components, indicating that the tone signal is being received.
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9. A tone detection circuit comprising:
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a first sampler that samples an in-phase signal component to produce a plurality of sampled in-phase signal components; a second sampler that samples a quadrature signal component to produce a plurality of sampled quadrature signal components; a signal shifter that shifts the plurality of sampled in-phase signal components by a predetermined phase angle to produce a plurality of shifted in-phase signal components; a comparator that compares a set of phase shifted in-phase signal components with a set of the plurality of sampled quadrature signal components; and tone reception indicator, operably coupled to the comparator, that indicates when a tone signal is being received when each phase shifted in-phase signal component of the set of phase shifted in-phase signal components substantially matches each corresponding sampled quadrature signal component of the set of the plurality of sampled quadrature signal components. - View Dependent Claims (10, 11, 12, 13)
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14. A method for a cellular telephone to detect a tone signal, the method comprising the steps of:
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a) receiving an input signal; b) converting the input signal in to an in-phase signal component and a quadrature signal component; c) sampling the in-phase signal component with a first sampler to produce a plurality of sampled in-phase signal components; d) sampling the quadrature signal component with a second sampler to produce a plurality of sampled quadrature signal components; e) shifting the plurality of sampled quadrature signal components by a predetermined phase angle to produce a plurality of phase shifted quadrature components; f) comparing a set of phase shifted quadrature components with a set of sampled in-phase signal components; and g) when each phase shifted quadrature component of the set of phase shifted quadrature components substantially matches each corresponding sampled in-phase signal component of the set of the sampled in-phase signal components, indicating that the tone signal is being received.
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15. A cellular telephone comprising:
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a transceiver; an audio processor operably coupled to the transceiver; a tone detection circuit, operably coupled to the transceiver, wherein the tone detection circuit includes; a first sampler that samples an in-phase signal component to produce a plurality of sampled in-phase signal components; a second sampler that samples a quadrature signal component to produce a plurality of sampled quadrature signal components; a signal shifter that shifts the plurality of sampled in-phase signal components by a predetermined phase angle to produce a plurality of shifted in-phase signal components; a comparator that compares a set of phase shifted in-phase signal components with a set of the plurality of sampled quadrature signal components; and tone reception indicator, operably coupled to the comparator, that indicates when a tone signal is being received when each phase shifted in-phase signal component of the set of phase shifted in-phase signal components substantially matches each corresponding sampled quadrature signal component of the set of the plurality of sampled quadrature signal components.
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16. A tone detection circuit comprising:
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a first sampler that samples an in-phase signal component to produce a plurality of sampled in-phase signal components; a second sampler that samples a quadrature signal component to produce a plurality of sampled quadrature signal components; a signal shifter that shifts the plurality of sampled quadrature signal components by a predetermined phase angle to produce a plurality of shifted quadrature signal components; a comparator that compares a set of phase shifted quadrature signal components with a set of the plurality of sampled in-phase signal components; and tone reception indicator, operably coupled to the comparator, that indicates when a tone signal is being received when each phase shifted quadrature signal component of the set of phase shifted quadrature signal components substantially matches each corresponding sampled in-phase signal component of the set of the plurality of sampled in-phase signal components.
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Specification