Sub-ranging digital to analog converter for radiofrequency amplification
First Claim
Patent Images
1. A circuit comprising:
- a first digital to analog converter for providing amplification of a signal based on a digital control word; and
, a second digital to analog converter, wherein a first plurality of bits representing the most significant bits of the digital control word are supplied to the first digital to analog converter, and a second plurality of bits representing the least significant bits of the digital control word are supplied to the second digital to analog converter, and wherein the second digital to analog converter supplies an analog representation of the second plurality of bits to the first digital to analog converter.
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Abstract
An apparatus and method for amplifying a radiofrequency signal using a main Digital to Analog Converter (RFDAC) and a subordinate Digital to Analog Converter (Sub-DAC). The main RFDAC provides a first portion of a N-bit digital output, which specifies the amplification level of the radiofrequency signal, and the sub-DAC provides a second portion of the N-bit digital word. Together, the main RFDAC and the Sub-DAC convert a complete N-bit digital word, where N specifies the resolution of the output radiofrequency signal.
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Citations
16 Claims
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1. A circuit comprising:
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a first digital to analog converter for providing amplification of a signal based on a digital control word; and
,a second digital to analog converter, wherein a first plurality of bits representing the most significant bits of the digital control word are supplied to the first digital to analog converter, and a second plurality of bits representing the least significant bits of the digital control word are supplied to the second digital to analog converter, and wherein the second digital to analog converter supplies an analog representation of the second plurality of bits to the first digital to analog converter. - View Dependent Claims (4, 6, 7)
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2. (canceled)
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3. (canceled)
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5. (canceled)
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8. A method for amplifying a signal, comprising the steps of:
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generating a first plurality of bit values representative of the most significant bits of a digital signal;
generating a second plurality of bit values representative of the least significant bits of the digital signal;
converting the second plurality of bit values into an analog signal; and
,modulating the amplitude of an input signal to generate an output signal based on the first plurality of bit values and the analog signal. - View Dependent Claims (9, 11)
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10. (canceled)
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12. A circuit comprising:
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a digital processing circuit coupled to an input terminal for converting an analog signal into at least two digital signals, at least one of said digital signals comprising an amplitude signal, and at least one of said digital signals comprising a phase signal; and
,a digital to analog circuit for applying an N-bit digital word to the phase signal, said digital to analog circuit comprising a first digital to analog converter and a second digital to analog converter, wherein a first plurality of bits representative of the most significant bits of the N-bit digital word are supplied to the first digital to analog converter, and wherein a second plurality of bits representative of a second portion the least significant bits of the N-bit digital word are supplied to the second digital to analog converter, and wherein the second digital to analog converter supplies an analog representation of the second plurality of bits of the N-bit digital word to the first digital to analog converter.
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13. A circuit comprising:
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a first digital to analog converter, said first digital to analog converter controlled by a most significant digital word; and
a second digital to analog converter, said second digital to analog converter controlled by a least significant digital word, wherein an output of the second digital to analog converter is combined with the most significant digital word to form a composite output digital word.
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14. A circuit comprising:
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a first digital to analog converter, said first digital to analog converter controlled by a most significant digital word; and
a second digital to analog converter, said second digital to analog converter controlled by a least significant digital word, wherein an output of the second digital to analog converter is applied to a least significant bit input of the first digital to analog converter, so that the output of the first digital to analog converter is finely controlled by the least significant digital word and coarsely controlled by the most significant digital word.
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15. A circuit comprising:
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a digital processing circuit coupled to an input terminal for converting an analog signal into at least two digital signals, at least one of said digital signals comprising an amplitude signal, and at least one of said digital signals comprising a phase signal; and
,a digital to analog circuit including;
a first digital to analog converter, said first digital to analog converter controlled by a most significant digital word; and
a second digital to analog converter, said second digital to analog converter controlled by a least significant digital word, wherein an output of the second digital to analog converter is combined with the most significant digital word to form a composite output.
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16. A circuit comprising:
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a first digital to analog converter for providing amplification of a signal based on a digital control word; and
,a second digital to analog converter, wherein a first plurality of bits representing a first portion of the digital control word are supplied to the first digital to analog converter, and a second plurality of bits representing a second portion of the digital control word are supplied to the second digital to analog converter, and wherein the second digital to analog converter supplies an analog representation of the second plurality of bits to the first digital to analog converter. wherein an output voltage of the circuit is defined by the following equation;
Vout=(VRF*CC)/2C+(VRF*CF)/2(C+F−
1),where Vout=output voltage, VRF=voltage of the signal to be amplified, CC=Most Significant Bit (MSB) binary code input to the first digital to analog converter, C=Most Significant Bit (MSB) resolution of the first digital to analog converter, CF=Least Significant Bit (LSB) binary code input to the second digital to analog converter, and F=Least Significant Bit (LSB) resolution of the second digital to analog converter.
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Specification