Briefly, a transmitter that includes first and second fractional N synthesizers that may generate outphased modulated signals. First and second sigma-delta modulators may control the modulation of the first and second fractional N synthesizers.
1. An apparatus comprising:
first and second fractional-N synthesizers to provide first and second, respective, modulated outphased signals; and
first and second sigma-delta modulators operably coupled to the first and second fractional-N synthesizers, respectively, wherein the first and second sigma-delta modulators are configured to modulate the first and second fractional-N synthesizers, respectively;
wherein one or both of the first and second sigma-delta modulators are configured to adjust an instantaneous frequency of one or both of the first and second fractional-N synthesizers, respectively, based on a desired power level of a transmitted frequency.
2. The apparatus of claim 1 , further comprising a combiner to combine the first and second modulated outphased signals and to provide a radio frequency transmission signal having a power level substantially equal to the desired power level of the transmitted frequency.
3. The apparatus of claim 2 , wherein the combiner comprises a reactive termination combiner associated with an adjustable amplifier.
4. The apparatus of claim 1 , further comprising first and second variable gain amplifiers to adjust amplitudes of the first and second modulated outphased signals, respectively.
5. An apparatus comprising:
first and second fractional-N synthesizers to provide first and second, respective, modulated outphased signals;
a digital signal processor that includes the first and second sigma-delta modulator modules to control an instantaneous frequency of the first and second fractional-N synthesizers, respectively, based on a desired transmitted frequency; and
a separator module to provide first and second phase derivatives to the first and second sigma-delta modulator modules, respectively.
6. An apparatus comprising:
first and second fractional-N synthesizers to provide first and second, respective, modulated outphased signals;
first and second sigma-delta modulators operably coupled to the first and second fractional-N synthesizers, respectively, wherein the first and second sigma-delta modulators are configured to modulate the first and second fractional-N synthesizers, respectively; and
a separator to provide first and second phase derivatives to the first and second sigma-delta modulators.
7. A method comprising:
separating an input signal into first and second phase-shifted signals;
generating first and second outphased signals by first and second fractional-N synthesizers, respectively, wherein the generating comprises modulating the first and second outphased signals using first and second sigma-delta modulators to generate modulated outphased signals, respectively; and
providing first and second phase derivatives of phases of the first and second phase-shifted signals, respectively, to the first and second sigma-delta modulators, respectively.
8. The method of claim 7 , further comprising:
combining the first and second modulated outphased signals; and
providing a transmission signal based on said combining of said modulated outphased signals.
9. The method of claim 7 , further comprising varying the amplitudes of the first and second modulated outphased signals.
10. A wireless communication system comprising:
a base station to transmit a desired power level value of a transmitted signal; and
a mobile station comprising a transmitter having first and second fractional-N synthesizers to provide first and second modulated outphased signals, respectively, and first and second sigma-delta modulators operably coupled to the first and second fractional-N synthesizers, respectively, to modulate the first and second outphased signals based on the desired power level value of the transmitted signal;
wherein one or both of the first and second sigma-delta modulators are able to adjust an instantaneous frequency of one or both of the first and second fractional-N synthesizers, respectively, based on a desired power level of a transmitted frequency.
11. The wireless communication system of claim 10 , wherein the transmitter further comprises a combiner to combine the first and second modulated outphased signals and to provide a radio frequency transmission signal having a power level substantially equal to the desired power level of the transmitted frequency.
12. The wireless communication system of claim 11 , wherein the combiner comprises a reactive termination combiner and an adjustable amplifier.
13. The wireless communication system of claim 10 , further comprising first and second variable amplifiers to adjust amplitudes of the first and second outphased modulated signals, respectively.
14. A wireless communication system comprising:
a base station to transmit a desired power level value of a transmitted signal;
a mobile station comprising a transmitter having first and second fractional-N synthesizers to provide first and second modulated outphased signals, respectively, first and second sigma-delta modulators operably coupled to the first and second fractional-N synthesizers, respectively, to modulate the first and second outphased signals based on the desired power level value of the transmitted signal, and a digital signal processor that includes the first and second sigma-delta modulator modules to control an instantaneous frequency of the first and second fractional-N synthesizers, respectively, based on a desired transmitted frequency.
15. The wireless communication system of claim 14 , wherein the digital signal processor comprises a separator module to provide first and second phase derivatives to the first and second sigma-delta modulators modules, respectively.
16. A wireless communication system comprising:
a base station to transmit a desired power level value of a transmitted signal; and
a mobile station comprising a transmitter having first and second fractional-N synthesizers to provide first and second modulated outphased signals, respectively, first and second sigma-delta modulators operably coupled to the first and second fractional-N synthesizers, respectively, to modulate the first and second outphased signals based on the desired power level value of the transmitted signal, and a separator to provide first and second phase derivatives to the first and second sigma-delta modulators.
17. An article comprising a storage medium, having stored thereon instructions that, when executed, result in:
separating an input signal into first and second phase-shifted signals;
generating first and second outphased signals by first and second fractional-N synthesizers, respectively;
modulating the first and second outphased signals using first and second sigma-delta modulators, respectively, to provide modulated outphased signals; and
providing first and second phase derivatives of phases of the first and second phase-shifted signals, respectively, to first and second sigma-delta modulators, respectively.
18. The article of claim 17 , wherein the instructions of providing, when executed, further result in:
combining the first and second modulated outphased signals; and
providing a transmission signal based on said combining of said modulated outphased signals.
19. The article of claim 17 , wherein the instructions of providing, when executed, further result in:
varying the amplitudes of the first and second modulated outphased signals.