Claims
- 1. A direct conversion circuit for radio frequency signals, said circuit comprising:a pair of quadrature related mixers coupled to a radio frequency signal input port for mixing down radio frequency input signals having a frequency of f1 in a first mode of operation, and alternatively for mixing down radio frequency input signals of a second frequency f2 in a second mode of operation where f1=2f2; and a local oscillator for producing a local oscillator signal, said local oscillator including a phase locked loop frequency multiplier for multiplying the frequency of a first voltage controlled oscillator signal by {fraction (4/3)} while said circuit is operating in said first mode of operation, said phase locked loop frequency multiplier including a frequency divider for dividing the signal by an integer that is a factor of 2 in the feedback path of the phase locked loop.
- 2. A direct conversion circuit as claimed in claim 1, wherein said first voltage controlled oscillator produces a signal having a frequency of about 1350 MHz.
- 3. A direct conversion circuit for radio frequency signals, said circuit comprising:a pair of quadrature related mixers coupled to a radio frequency signal input port for mixing down radio frequency input signals of about 1800 MHz in a first mode of operation, and for mixing down radio frequency input signals of about 900 MHz in a second mode of operation; and a local oscillator for producing a local oscillator signal at a frequency of fLO, said local oscillator including a non-integer frequency multiplier means for multiplying the frequency of a first voltage controlled oscillator signal by a non-integer number greater than one while said circuit is operating in said first mode of operation, and for dividing the frequency of the first voltage oscillator by a non-integer number greater than one while said circuit is operating in said second mode of operation.
- 4. A direct conversion circuit as claimed in claim 3, wherein said voltage controlled oscillator produces a signal having a frequency of 1350 MHz.
- 5. A direct conversion circuit for radio frequency signals, said circuit comprising:a pair of quadrature related mixers coupled to a radio frequency signal input port for mixing down radio frequency input signals of about 1800 MHz in a first mode of operation, and for mixing down radio frequency input signals of about 900 MHz in a second mode of operation; a phase shift device coupled to said pair of quadrature related mixers; a local oscillator for producing a local oscillator signal at a frequency of fLO, said local oscillator including a non-integer frequency multiplier means for multiplying the frequency of a first voltage controlled oscillator signal by a non-integer number; and a local oscillator path through which a local oscillator signal may pass from said local oscillator to said phase shift device, said local oscillator path including a local oscillator path switch and a frequency divider, the local oscillator path switch being movable between first and second positions such that said local oscillator signal may pass through said frequency divider when said switch is in said first position, and said local oscillator signal may by-pass said frequency divider when said switch is in said second position.
- 6. A direct conversion circuit as claimed in claim 5, wherein said frequency divider is a divide by two frequency divider.
- 7. A direct conversion circuit for radio frequency signals, said circuit comprising:a pair of quadrature related mixers coupled to a radio frequency signal input port for mixing down radio frequency input signals of about 1800 MHz in a first mode of operation, and for mixing down radio frequency input signals of about 900 MHz in a second mode of operation; and a local oscillator for producing a local oscillator signal at a frequency of fLO, said local oscillator including a non-integer frequency multiplier means for multiplying the frequency of a first voltage controlled oscillator signal by a non-integer number, said non-integer frequency multiplier means including a feedback loop through which a feedback signal may pass, said feedback loop including first and second frequency dividers, and a switch that is movable between first and second positions, said feedback signal passing through both frequency dividers when said switch is in said first position, and said feedback signal passing through one of the first or second dividers when said switch is in said second position.
- 8. A direct conversion circuit as claimed in claim 7, wherein each of said first and second frequency dividers is a divide by two frequency divider.
- 9. A direct conversion circuit as claimed in claim 7, wherein said voltage controlled oscillator signal has a frequency of 1350 MHz., and said local oscillator provides non-integer frequency multiplication of {fraction (4/3)} while said circuit is operating in said first mode of operation, and provides non-integer frequency multiplication of ⅔ while said circuit is operating in said second mode of operation.
Parent Case Info
This patent application is a continuation-in-part patent application of U.S. Ser. No. 09/133,781 filed on Aug. 12, 1998 now U.S. Pat. No. 6,243,569.
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GB |
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JP |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
09/133781 |
Aug 1998 |
US |
Child |
09/785383 |
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US |