POLAR TRANSMITTER, METHOD AND APPARATUS FOR PHASE MODULATION
First Claim
1. A phase modulator, adaptable for a polar transmitter to generate a phase varying radio frequency (RF) signal based on a phase sample, comprising:
- a loop control unit, designating a target frequency based on a reference frequency, the phase sample and the RF signal;
a logic control unit, generating an oscillator control word based on the target frequency;
a digital oscillator, having a capability to modulate from a first phase to a second phase, for synthesizing a preliminary RF signal based on the oscillator control word;
wherein the first phase and the second phase are separated by 180 degrees;
a phase switch, coupled to the digital oscillator and the logic control unit, selectively shifting the preliminary RF signal by 180 degrees based on a switch signal;
wherein,when the target frequency exceeds the modulation capability of the digital oscillator, the logic control unit generates the oscillator control word based on the target frequency minus 180 degrees, and sends a switch signal to direct the phase switch to shift the preliminary RF signal by 180 degrees, such that the RF signal is synthesized to have the target frequency, andwhen the target frequency does not exceed the modulation capability of the digital oscillator, the logic control unit generates the oscillator control word solely based on the target frequency, and the phase switch directly outputs the preliminary RF signal to be the RF signal having the target frequency.
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Abstract
A phase modulation method with a polar transmitter. A target frequency is first designated by comparing the RF signal with a reference frequency and the phase sample. An oscillator control word is generated based on the target frequency. A digital oscillator can modulate from a first phase to a second phase to synthesize a preliminary RF signal based on the oscillator control word. When the target frequency exceeds the modulation capability of the digital oscillator, the oscillator control word is generated based on the target frequency minus 180 degrees, and the preliminary RF signal is shifted by 180 degrees to be the RF signal having the target frequency. When the target frequency does not exceed the modulation capability of the digital oscillator, the oscillator control word is generated solely based on the target frequency to output the preliminary RF signal to be the RF signal having the target frequency.
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Citations
36 Claims
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1. A phase modulator, adaptable for a polar transmitter to generate a phase varying radio frequency (RF) signal based on a phase sample, comprising:
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a loop control unit, designating a target frequency based on a reference frequency, the phase sample and the RF signal; a logic control unit, generating an oscillator control word based on the target frequency; a digital oscillator, having a capability to modulate from a first phase to a second phase, for synthesizing a preliminary RF signal based on the oscillator control word;
wherein the first phase and the second phase are separated by 180 degrees;a phase switch, coupled to the digital oscillator and the logic control unit, selectively shifting the preliminary RF signal by 180 degrees based on a switch signal;
wherein,when the target frequency exceeds the modulation capability of the digital oscillator, the logic control unit generates the oscillator control word based on the target frequency minus 180 degrees, and sends a switch signal to direct the phase switch to shift the preliminary RF signal by 180 degrees, such that the RF signal is synthesized to have the target frequency, and when the target frequency does not exceed the modulation capability of the digital oscillator, the logic control unit generates the oscillator control word solely based on the target frequency, and the phase switch directly outputs the preliminary RF signal to be the RF signal having the target frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A polar transmitter, for synthesizing an RF signal from a baseband signal, comprising:
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a polar processor, transforming the baseband signal into a magnitude sample and a phase sample; a magnitude modulator, generating a magnitude control signal based on the magnitude sample; a phase modulator, using the phase sample to synthesize the RF signal having variable phases; and a digital power amplifier, receiving the magnitude control signal to amplify and transmit the RF signal, wherein, the phase modulator comprises; a loop control unit, designating a target frequency based on a reference frequency, the phase sample and the RF signal; a logic control unit, generating an oscillator control word of binary form based on the target frequency; a digital oscillator, having a capability to modulate from a first phase to a second phase, for synthesizing a preliminary RF signal based on the oscillator control word; and a phase switch, coupled to the digital oscillator and the logic control unit, selectively shifting the preliminary RF signal by 180 degrees based on a switch signal;
wherein;when the target frequency exceeds the modulation capability of the digital oscillator, the logic control unit generates the oscillator control word based on the target frequency minus 180 degrees, and sends a switch signal to direct the phase switch to shift the preliminary RF signal by 180 degrees, such that the RF signal is synthesized to have the target frequency; and when the target frequency does not exceed the modulation capability of the digital oscillator, the logic control unit generates the oscillator control word solely based on the target frequency, and the phase switch directly outputs the preliminary RF signal to be the RF signal having the target frequency. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A phase modulation method, adaptable for a polar transmitter to generate a radio frequency (RF) signal of variable phases based on a phase sample, comprising:
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designating a target frequency by comparing the RF signal with a reference frequency and the phase sample; generating an oscillator control word based on the target frequency; providing a digital oscillator having a capability to modulate from a first phase to a second phase, for synthesizing a preliminary RF signal based on the oscillator control word; when the target frequency exceeds the modulation capability of the digital oscillator, generating the oscillator control word based on the target frequency minus 180 degrees, and shifting the preliminary RF signal by 180 degrees to be the RF signal having the target frequency; and when the target frequency does not exceed the modulation capability of the digital oscillator, generating the oscillator control word solely based on the target frequency, and directly outputting the preliminary RF signal to be the RF signal having the target frequency. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification