Claims
- 1. Apparatus for reducing frequency pulling of an output VCO involving AM modulation wherein the output frequency is structured to be larger than a synthesizer VCO frequency by a factor greater than unity to maintain a non-harmonic relation between the synthesizer and the output VCO, the apparatus comprising:a source for signals; the synthesizer for synthesizing said signals being in communication with a first frequency divider; a second frequency divider connected to the output VCO; a third frequency divider connected to said second frequency divider and further connected to said synthesizer; a mixer connected to the transmission side of the output VCO and further connected to the transmission side of said second frequency divider; a pretransmission filter connected to said mixer on the transmission side; and an amplifier connected to the pretransmission filter and further connected to a transmitter; the output frequency at said amplifier being non-harmonically related to the synthesizer VCO to thereby minimize frequency pulling during the AM modulation of the output VCO.
- 2. The apparatus of claim 1, wherein said mixer is structured to accept about 100% of the frequency from the output VCO and further accept a frequency input equal to about 50% of the output VCO.
- 3. The apparatus of claim 1, wherein said third frequency divider is structured to distribute 1N×50%of the frequency from the output VCO to the phase detector.
- 4. A frequency pulling reduction architecture implemented in an AM modulation process wherein spurious responses resulting from mixing products are eliminated, the architecture comprising:a frequency transmitter scheme having a 3/2 frequency output; a frequency synthesizer; and said frequency output being developed from a VCO for both said transmitter and being non-harmonically related to a VCO frequency of said synthesizer.
- 5. The architecture according to claim 4, wherein said transmitter scheme includes a frequency source and a frequency divider.
- 6. The architecture according to claim 4, wherein said frequency synthesizer is coupled to a plurality of conditioned frequencies at the input side and a low pass filter at the output side.
- 7. The architecture according to claim 4, wherein said 3/2 frequency output comprises conditioned frequencies from a frequency source and said VCO.
- 8. A method of reducing frequency pulling in an AM modulation process wherein spurious responses resulting from mixing devices are eliminated, the method comprising the steps of:generating a VCO output frequency equal to a value obtained from a source frequency conditioned by a plurality of frequency dividers and phase detectors; introducing said VCO output into a mixer; adding ½ of said VCO output into said mixer via one of said frequency dividers; introducing ½ of said VCO output into said synthesizer via one of said plurality of frequency dividers; and producing a frequency output equal to 1.5 times greater than said VCO output frequency at an output amplifier.
- 9. The method according to claim 8, wherein said step of introducing ½ of said VCO output into said synthesizer includes the step of apportioning ½ of said VCO frequency using a ½ frequency divider to generate an output frequency equal to ½ the VCO frequency (FVCO).
- 10. The method according to claim 9, wherein said step of apportioning includes the step of directing ½ of the FVCO into two opposite directions wherein one of the opposite directions feeds into a mixer.
- 11. The method according to claim 10, wherein said step of directing includes introducing ½ of the FVCO into a divider which ultimately feeds into the phase detector.
- 12. The method according to claim 8, wherein said step of producing a frequency output includes mixing output frequencies of FVCO and ½ FVCO in a mixer to generate a frequency output equal to 3/2 FVCO.
RELATED APPLICATION
This application claims the benefit of U.S. Provisional Application No. 60/120,641, filed Feb. 18,1999.
US Referenced Citations (9)
Provisional Applications (1)
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Number |
Date |
Country |
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60/120641 |
Feb 1999 |
US |