Method and apparatus for adapting a receiver frequency plan according to location
First Claim
1. A selectable frequency source for use in a Global Positioning System (GPS) receiver, comprising:
- a reference frequency source;
a first divider, coupled to the reference frequency source, the first divider having a first dividing factor;
a first mixer, coupled to the first divider;
a filter, coupled to the first mixer;
a voltage controlled oscillator, coupled to the filter;
a second divider, coupled between the voltage controlled oscillator and the first mixer, the second divider having a second dividing factor; and
a second mixer, coupled to an output of the voltage controlled oscillator, for controlling the frequency of the voltage controlled oscillator, wherein at least one of the first dividing factor and the second dividing factor is automatically changed to change a frequency output of the voltage controlled oscillator, in response to an external interfering signal.
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Accused Products
Abstract
A selectable frequency source for use in GPS receivers. A device in accordance with the present invention comprises a reference frequency source, a first divider, coupled to the reference frequency source, the first divider having a first dividing factor, a first mixer, coupled to the first divider, a filter, coupled to the first mixer, a voltage controlled oscillator, coupled to the filter, a second divider, coupled between the voltage controlled oscillator and the first mixer, the second divider having a second dividing factor, and a second mixer, coupled to an output of the voltage controlled oscillator, for mixing a GPS signal with the output of the voltage controlled oscillator, wherein at least one of the first dividing factor and the second dividing factor is changed to change a frequency output of the voltage controlled oscillator.
17 Citations
20 Claims
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1. A selectable frequency source for use in a Global Positioning System (GPS) receiver, comprising:
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a reference frequency source; a first divider, coupled to the reference frequency source, the first divider having a first dividing factor; a first mixer, coupled to the first divider; a filter, coupled to the first mixer; a voltage controlled oscillator, coupled to the filter; a second divider, coupled between the voltage controlled oscillator and the first mixer, the second divider having a second dividing factor; and a second mixer, coupled to an output of the voltage controlled oscillator, for controlling the frequency of the voltage controlled oscillator, wherein at least one of the first dividing factor and the second dividing factor is automatically changed to change a frequency output of the voltage controlled oscillator, in response to an external interfering signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A selectable frequency source for use in a Global Positioning System (GPS) receiver, comprising:
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a reference frequency source generating a reference frequency; a circuit, coupled to the reference frequency source, the circuit having an output frequency which is scaled in relation to the reference frequency; a mixer, coupled to the circuit, wherein the output frequency of the circuit is automatically changed to change a frequency output of the mixer in response to a presence of an external interfering signal. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method fox changing a local oscillator frequency in a Global Positioning System (GPS) receiver, comprising:
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determining that the GPS receiver is in a predetermined geographic region; and automatically changing the local oscillator frequency when the GPS receiver is in the predetermined geographic region in response to a presence of an external interfering signal. - View Dependent Claims (19, 20)
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Specification