Base station having high speed, high resolution, digital-to-analog converter with off-line sigma delta conversion and storage
First Claim
1. A base station, comprising:
- a baseband processor having at least two data inputs;
a high speed, high resolution, digital-to-analog converter (DAC) coupling said baseband processor to a modulator;
an up-converter coupling said modulator to a power amplifier; and
an antenna coupled to said power amplifier.
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Accused Products
Abstract
A wireless base station having an improved DAC operable at higher speed than heretofore achievable which exploits the sigma-delta principle in a different way. More particularly, the invention comprises a base station 300 that implement a digital-to-analog conversion circuit (105) including a storage means (110), such as a read only memory, for storing delta-sigma analog sequences corresponding to all possible values of a digital input (106) coupled to a plurality of one-bit digital to analog converters (120, 122, 124, 126). Each of the digital-to-analog converters (120, 122, 124, 126) are clocked by multi-phase clocks, such that each phase applied to each one of the digital-to-analog converters (120, 122, 124, 126) is delayed with respect to one another by the oversampling period. An summer is coupled to each digital-to-analog converter (120, 122, 124, 126) for summing each output from each digital-to-analog converter (120, 122, 124, 126) to generate an analog output. Hereby, the digital-to-analog conversion circuit (105) according to the invention emulates a delta-sigma digital-to-analog converter having both high speed and high resolution.
36 Citations
24 Claims
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1. A base station, comprising:
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a baseband processor having at least two data inputs;
a high speed, high resolution, digital-to-analog converter (DAC) coupling said baseband processor to a modulator;
an up-converter coupling said modulator to a power amplifier; and
an antenna coupled to said power amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
a storage means having stored outputs of a delta-sigma converter fed by a number of predetermined interpolated samples corresponding to all possible values of at least one of said data inputs;
said storage means coupled to receive said data input;
a plurality of digital-to-analog converters coupled to said storage means to receive said stored outputs, said plurality of digital-to-analog converters clocked by multi-phase clocks wherein each phase applied to each of said plurality of digital to analog converters is delayed with respect to a next one by an oversampling period equal to the Nyquist period divided by the number of predetermined interpolated samples; and
a summer coupled to said plurality of digital-to-analog converters for summing all output from said plurality of digital-to-analog converters to generate said analog output.
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12. The base station of claim 11 wherein said storage means is a read/write programmable memory.
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13. The base station of claim 11 wherein said storage means is a read only memory.
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14. The base station of claim 11 wherein said digital baseband further comprises:
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a digital signal processor (DSP);
a microcontroller unit (MCU) coupled to said DSP; and
an ASIC backplane coupled to said DSP and said MCU.
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15. The base station of claim 1 wherein said analog baseband comprises an RF interface coupled to said DSP and to said RF section.
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16. The base station of claim 1 wherein said base station is a cellular base station.
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17. The base station of claim 1 wherein said baseband processor is a digital baseband processor.
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18. The base station of claim 1 wherein said data inputs provide digital data.
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19. The base station of claim 1 wherein said at least two data inputs receive input from Plain Old Telephone lines (POTS).
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20. The base station of claim 1 wherein said base station simultaneously sends information from multiple inputs over an RF transmission.
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21. The base station of claim 20 wherein said RF transmission is divided into multiple RF channels.
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22. A base station, comprising:
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circuitry for providing a digital baseband function;
circuitry, responsive to said digital baseband function, for providing a high speed, high resolution, digital-to-analog conversion function;
circuitry, responsive to said high speed, high resolution, digital-to-analog conversion function, for modulating said converted analog signal;
circuitry, responsive to said modulator function, for up-converting said modulated and converted analog signal to a broad cast frequency; and
circuitry, responsive to said being responsive to said up-converting function, for amplifying said up-converted signal and coupling said amplified signal to an antenna. - View Dependent Claims (23, 24)
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Specification