Up/down conversion circuitry for radio transceiver
First Claim
1. Down conversion circuitry for use in a radio transceiver for down converting a received RF information signal to a base band information signal in two stages wherein a first said stage converts said RF information signal to an IF information signal and a second said stage converts said IF information signal to said base band information signal, said down conversion circuitry comprising:
- a mixer component configured for down converting said RF information signal to said IF information signal using an RF oscillator signal;
an image rejection mixer component configured for down converting said IF information signal to said base band signal using an IF oscillator signal and achieving image signal rejection of said IF information signal; and
,a frequency synthesizer configured for generating one or more of said RF or IF oscillator signals, or combinations thereof, wherein said IF oscillator signal is an integer (N) sub-harmonic of said RF oscillator signal and a frequency value of said IF oscillator signal is pre-selected to be within an operating frequency band of said image rejection mixer component.
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Accused Products
Abstract
A multi-channel RF receiver uses an image rejection mixer (e.g. double quadrature mixer) in the IF down conversion stage for image side band rejection (whereby use of an IF narrow band filter for image rejection may be omitted if desired) and comprises a simplified frequency synthesizer which generates both a “wandering” IF oscillator frequency and an RF oscillator frequency for the up/down conversion stages (being, for down conversion, from RF to IF and from IF to base band. The IF used for a particular RF carrier (channel) is selected so as to be both an integer (N) sub-harmonic of that RF carrier and within the operating frequency band of the image rejection mixer. Advantageously, the synthesizer comprises only one loop and one VCO, wherein the IF oscillator signal is produced from the RF oscillator signal by means of a frequency divider.
89 Citations
21 Claims
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1. Down conversion circuitry for use in a radio transceiver for down converting a received RF information signal to a base band information signal in two stages wherein a first said stage converts said RF information signal to an IF information signal and a second said stage converts said IF information signal to said base band information signal, said down conversion circuitry comprising:
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a mixer component configured for down converting said RF information signal to said IF information signal using an RF oscillator signal; an image rejection mixer component configured for down converting said IF information signal to said base band signal using an IF oscillator signal and achieving image signal rejection of said IF information signal; and
,a frequency synthesizer configured for generating one or more of said RF or IF oscillator signals, or combinations thereof, wherein said IF oscillator signal is an integer (N) sub-harmonic of said RF oscillator signal and a frequency value of said IF oscillator signal is pre-selected to be within an operating frequency band of said image rejection mixer component. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for use in a radio transceiver for down converting, in two stages, a received RF information signal to a base band information signal wherein a first said stage converts said RF information signal to an IF information signal and a second said stage converts said IF information signal to said base band information signal, said method comprising:
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down converting said RF information signal to said IF information signal using an RF oscillator signal; down converting said IF information signal to said base band signal to provide image signal rejection, and an IF oscillator signal; and generating one or more of said RF or IF oscillator signals, or combinations thereof, wherein said IF oscillator signal comprises an integer (N) sub-harmonic of said RF oscillator signal, said generating including preselecting the frequency value of said IF oscillator signal to be within an operating frequency band of said down converting said IF information signal. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. An apparatus, comprising:
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means for down converting an RF information signal to an IF information signal using an RF oscillator signal; means for down converting the IF information signal to a base band signal to provide image signal rejection, and to provide an IF oscillator signal; and means for generating one or more of the RF oscillator signal or the IF oscillator signal, or combinations thereof, wherein the IF oscillator signal comprises an integer (N) sub-harmonic of the RF oscillator signal, and for preselecting the frequency value of the IF oscillator signal to be within an operating frequency band of said IF information signal down converting means. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification