Method and apparatus for mismatched shaping of an oversampled converter
AssigneeBroadcom Corporation
InventorsTodd L. Brooks, David S. P. Ho, Kevin L. Miller, Eric Fogleman
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Abstract
Methods and apparatuses for spectrally shaping mismatch errors in a multi-bit digital to analog converter (DAC). In an embodiment, a range signal is produced based on the digital input code. The range signal specifies which one of a plurality of ranges the digital input code is within. A density code is also produced, preferably, using a shuffling algorithm. The density code specifies a level within the range expressed by the range signal. The range signal and the density code are then combined to produce a plurality of sub-codes, a sum of the plurality of sub-codes equaling the digital input code.
Claims40
A method for mismatch shaping, comprising the steps of:
- (a) receiving a digital input code;
- (b) producing a range signal based on the digital input code, the range signal specifying one of a plurality of ranges the digital input code is within;
- (c) producing a density code, the density code specifying a level within the range expressed by the range signal;
- and
- (d) combining the range signal and the density code to thereby produce a plurality of sub-codes, a sum of the plurality of sub-codes equaling the digital input code.
A method for mismatch shaping, comprising the steps of:
- receiving a digital input code having a first value V1;
- producing a second digital value V2, wherein V2 equals a greatest integer less than V1÷K, where K>2;
- producing a third digital value V3, wherein V3 equals V1 modulo K;
- producing a shuffled density code based on the third digital value V3, wherein the shuffled density code includes K bits each of which has a value of 0 or 1, and wherein an order of the K bits with respect to one another is based on a shuffling algorithm;
- separately adding V2 to each of the K bits to produce K separate further digital outputs V41 . . . V4K, wherein a sum of the K separate further digital outputs equals the first value V1 [ i . e . , ∑ i = 1 k V4 i = V1 ] .
An apparatus for mismatch shaping, comprising:
- a range selector to produce a range signal based on the digital input code, the range signal specifying one of a plurality of ranges the digital input code is within;
- a density generator to produce a density code, the density code specifying a level within the range expressed by the range signal;
- and
- a combiner to combine the range signal and the density code to produce a plurality of sub-codes, a sum of the plurality of sub-codes equaling the digital input code.
An apparatus for mismatch shaping, comprising:
- means for receiving a digital input code having a first value V1;
- means for producing a second digital value V2, wherein V2 equals a greatest integer less than V1÷K, where K>2;
- means for producing a third digital value V3, wherein V3 equals V1 modulo K;
- means for producing a shuffled density code based on the third digital value V3, wherein the shuffled density code includes K bits each of which has a value of 0 or 1, and wherein an order of the K bits with respect to one another is based on a shuffling algorithm;
- and
- means for separately adding V2 to each of the K bits to produce K separate further digital outputs V41 . . . V4K, wherein a sum of the K separate further digital outputs equals the first value V1 [ i . e . , ∑ i = 1 k V4 i = V1 ] .
Dependencies are inferred from the claim text.