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US 2009/0267818 A1Published application
Low distortion current switch
AssigneeAnalog Devices, Inc.
InventorWilliam George John SCHOFIELD
Life of this patent
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Abstract
A system and method is provided for code independent switching in a digital-to-analog converter (DAC). A synchronous digital circuit is triggered by a synchronizing clocking signal and develops a digital data signal. A circuit arrangement provides the synchronizing clock a constant load at every clocking cycle, thereby assuring a data independent load. By providing a data independent load to the synchronizing clock at every clocking cycle, third harmonic distortion is advantageously reduced.
Claims10
A complementary digital control circuitry for a DAC comprising:
- a synchronous digital circuit triggered by a clocking signal and providing at least one digital output signal;
- a first input for receiving a digital signal;
- a second input for receiving a complement of said digital signal;
- an SR latch for storing the digital signal and the complement digital signal received at said first input and said second input, respectively;
- and
- a plurality of switching elements arranged so that said clocking signal drives a load substantially independently of the state of said first input and said second input, reducing third harmonic distortion.
3 more elements
A method of signal processing comprising:
- pre-charging a first input and a second input to the same predetermined logic level;
- receiving a digital signal at said first input;
- receiving a complement of said digital signal at said second input;
- and
- providing complementary digital signals with a synchronous digital circuit triggered by a clocking signal, wherein a plurality of switching elements are arranged such that said clocking signal has a load of a constant number of said switching elements changing conduction state with every cycle of said clocking signal, reducing third harmonic distortion.
2 more elements
Dependencies are inferred from the claim text.