Method and system for digital to analog conversion for power amplifier driver amplitude modulation
View Patent ↗Aspects of a method and system for digital to analog conversion for power amplifier driver amplitude modulation are presented. Various aspects of the system may include circuitry that enables oversampling, within a single integrated circuit device, of each of a plurality of samples in a digital baseband signal. The circuitry may enable reduction of a number of bits, i.e., coarse quantization, in each of the oversampled plurality of samples so as to cause displacement of the quantization noise that occurred as a result of the coarse quantization. A subsequent signal may be generated based on the oversampled signal. The circuitry may enable the subsequent signal to be low-pass filtered utilizing filter circuitry in the single integrated circuit device, thereby attenuating the quantization noise displaced into the higher frequency range of the oversampled signal.
1. A method for amplitude modulation in a wireless communication system, the method comprising:
oversampling, within a single integrated circuit device, each of a plurality of samples in a baseband signal;
reducing a number of bits in each of said oversampled plurality of samples so as to cause, based on a generated pseudo random bit sequence, displacement of quantization noise that occurred as a result of said oversampling; and
low-pass filtering within said single integrated circuit device, a subsequent signal comprising said reduced number of bits.
2. The method according to claim 1 , wherein each of said plurality of samples in said baseband signal comprises an M-bit binary data word, that is converted to at least one of a plurality of K signal levels where K and M represent numbers, wherein said value of K is less than 2 M .
3. The method according to claim 2 , comprising generating said subsequent signal comprising a current one of said plurality of K signal levels, followed by a zero signal level, followed by a subsequent one of said plurality of K signal levels.
4. The method according to claim 3 , comprising converting each of said at least one of said plurality of K signal levels to a corresponding N-bit binary data word, wherein N represents a number.
5. The method according to claim 4 , wherein one of: a lowest and a highest, value for said N-bit binary data word corresponds to one of: a highest and a lowest, value for one of said plurality of K signal levels.
6. The method according to claim 4 , wherein a value for said N-bit binary data word that is greater than a lowest value and less than a highest value for said N-bit binary data word corresponds to a value for one of said plurality of K signal levels that is greater than a lowest level and less than a highest level for said one of said plurality of K signal levels.
7. The method according to claim 4 , comprising generating switching control bits based on said N-bit binary data word and bits generated based on said generated pseudo random bit sequence.
8. The method according to claim 7 , wherein said switching control bits are differentially encoded.
9. The method according to claim 8 , comprising selecting one of said plurality of K signal levels based on values for positive polarity bits in said differentially encoded switching control bits.
10. The method according to claim 8 , comprising generating a zero signal level based on values for negative polarity bits in said differentially encoded switching control bits.
11. The method according to claim 8 , comprising generating said subsequent signal comprising one of said plurality of K signal levels based on current values for positive polarity bits in said differentially encoded switching control bits, followed by a zero signal level based on values for negative polarity bits in said differentially encoded switching control bits, followed by a subsequent one of said plurality of K signal levels based on subsequent values for said positive polarity bits in said differentially encoded switching control bits.
12. The method according to claim 11 , wherein said current values for said positive polarity bits are binary complements to corresponding subsequent values for said positive polarity bits based on said generated pseudo random bit sequence.
13. A system for amplitude modulation in a wireless communication system, the method comprising:
one or more circuits within a single integrated circuit device that enable oversampling of each of a plurality of samples in a baseband signal;
said one or more circuits enable reduction of a number of bits in each of said oversampled plurality of samples so as to cause, based on a generated pseudo random bit sequence, displacement of quantization noise that occurred as a result of said oversampling; and
said one or more circuits enable low-pass filtering of a subsequent signal comprising said reduced number of bits.
14. The system according to claim 13 , wherein each of said plurality of samples in said baseband signal comprises an M-bit binary data word, that is converted to at least one of a plurality of K signal levels where K and M represent numbers, wherein said value of K is less than 2 M .
15. The system according to claim 14 , wherein said one or more circuits enable generation of said subsequent signal comprising a current one of said plurality of K signal levels, followed by a zero signal level, followed by a subsequent one of said plurality of K signal levels.
16. The system according to claim 15 , wherein said one or more circuits enable conversion of each of said at least one of said plurality of K signal levels to a corresponding N-bit binary data word, wherein N represents a number.
17. The system according to claim 16 , wherein one of: a lowest and a highest, value for said N-bit binary data word corresponds to one of: a highest and a lowest, value for one of said plurality of K signal levels.
18. The system according to claim 16 , wherein a value for said N-bit binary data word that is greater than a lowest value and less than a highest value for said N-bit binary data word corresponds to a value for one of said plurality of K signal levels that is greater than a lowest level and less than a highest level for said one of said plurality of K signal levels.
19. The system according to claim 16 , wherein said one or more circuits enable generation of switching control bits based on said N-bit binary data word and bits generated based on said generated pseudo random bit sequence.
20. The system according to claim 19 , wherein said switching control bits are differentially encoded.
21. The system according to claim 20 , wherein said one or more circuits enable selection of one of said plurality of K signal levels based on values for positive polarity bits in said differentially encoded switching control bits.
22. The system according to claim 20 , wherein said one or more circuits enable generation of a zero signal level based on values for negative polarity bits in said differentially encoded switching control bits.
23. The system according to claim 20 , wherein said one or more circuits enable generation of said subsequent signal comprising one of said plurality of K signal levels based on current values for positive polarity bits in said differentially encoded switching control bits, followed by a zero signal level based on values for negative polarity bits in said differentially encoded switching control bits, followed by a subsequent one of said plurality of K signal levels based on subsequent values for said positive polarity bits in said differentially encoded switching control bits.
24. The system according to claim 23 , wherein said current values for said positive polarity bits are binary complements to corresponding subsequent values for said positive polarity bits based on said generated pseudo random bit sequence.