Electric signal conversion
AssigneeAnalog Devices Technology
InventorsTrevor Clifford Caldwell, Richard E. Schreier, David Alldred, Wenhua W. Yang
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Abstract
In one aspect, an electrical signal converter is disclosed. The exemplary electrical signal converter may include a plurality of ordered converter elements. Element selection logic may be provided to pseudorandomly select a pointer to a switch matrix, wherein the switch matrix maps converter elements according to a stepwise “delta-two-maximum pattern.” Advantageously, pseudorandom stepwise delta-two-maximum patterns may be applied both to a first order converter, and to a feedback converter for error correction.
Claims23
An electrical signal converter, comprising:
- a plurality of inputs for receiving a first species of signal;
- a plurality of n, converter elements for converting the first species of signal into a second species of signal, wherein n>3;
- a switch for mapping the plurality of inputs to the plurality of converter elements;
- and
- logic configured to cause the switch to map the inputs on a plurality of successive input cycles to different converter elements according to a delta-two-maximum pattern, wherein on a first input cycle, a converter element is used at position k, and on a second conversion cycle the converter element is used at position kt+1, wherein |k−kt+1|≦2.
A delta-sigma modulator comprising:
- an analog-to-digital converter configured to receive an analog input and provide a digital output, the analog-to-digital converter comprising a plurality of n ordered converter elements, wherein n>3, and logic to rotate converter elements according to a first stepwise delta-two-maximum pattern;
- a digital-to-analog converter configured to receive the digital output of the analog-to-digital converter and provide an analog output, the digital-to-analog converter comprising a plurality of ordered converter elements and logic rotate converter elements according to a second stepwise delta-two-maximum pattern;
- a loop filter configured to receive the analog input and the analog output of the digital-to-analog converter, and to provide a filtered analog signal the analog-to-digital converter;
- and
- element selection logic configured to select a number of steps;
- wherein the first stepwise delta-two-maximum pattern and second stepwise delta-two-maximum pattern each ensure that a converter element used at a position k on a first conversion cycle is used at kt+1 on a second conversion cycle, wherein |k−kt+1|≦2.
A method performed by an electrical signal converter, comprising:
- during a first time period, selecting a first converter element from among a plurality of n available ordered converter elements in the electrical signal converter, wherein n>3;
- during a second time period:
- calculating a pseudorandom number;
- selecting a second converter element by stepping through available converter elements according to a delta-two-maximum pattern, the number of steps being a function of the pseudorandom number and being less than two.
Dependencies are inferred from the claim text.