State-delayed technique and system to remove tones of dynamic element matching
AssigneeBroadcom Corporation
InventorMinsheng Wang
Life of this patent
Estimating the term…
Abstract
A filter structure used with a dynamic element matching encoder for a sigma-delta digital-to-analog converter is presented. A sampled input sequence having undesired frequency tones is divided into even and odd data sub-sequences. Each of the sub-sequences is processed by a dynamic element matching encoder, with a transfer function H(z−1). The resulting processed sub-sequences are combined into an output sequence. The undesired frequency tones are substantially reduced in the output sequence.
Claims24
A method of performing dynamic element matching (DEM) on an input data stream having a data sample, rate equal to Fs, the input data stream including alternating even and odd input data samples, comprising:
- a. performing a DEM operation on each of the even input data samples to produce shuffled even data samples;
- b. performing a DEM operation on each of the odd input data samples to produce shuffled odd data samples;
- and
- c. combining in an alternating manner the shuffled even and odd data samples to produce an output data stream, wherein Fs/2 tones produced by the DEM operations of steps (a) and (b) are substantially reduced in the output data stream.
A method of performing dynamic element matching (DEM) on an input data stream having a data sample rate equal to Fs, the input data stream including alternating even and odd incoming data samples, each separated from the next by one sample period, comprising:
- a. determining a new state of a swapper based on an incoming data sample and a current state of the swapper, wherein the current state of the swapper has been delayed for at least one sample period;
- b. delaying the new state of the swapper for at least one sample period;
- and
- c. repeating steps (a) and (b) for each incoming data sample.
A method of performing data weighted averaging (DWA) on an input data stream having a data sample rate equal to Fs, the input data stream including alternating even and odd incoming data samples, each separated from the next by one sample period, comprising:
- a. determining a new DAC pointer position based on an incoming data sample and a current DAC pointer position, wherein the current DAC pointer position has been delayed for at least one sample period;
- b. delaying the new DAC pointer position for at least one sample period;
- and
- c. repeating steps (a) and (b) for each incoming data sample.
A system configured to perform dynamic element matching (DEM) on an input data stream having a sample rate equal to Fs, the input data stream including alternating even and odd input data samples, comprising:
- a. an input stage configured to form from the input data stream:
- i. an even data stream including the even input data samples, and
- ii. an odd data stream including the odd input data samples;
- b. a first stage configured to perform a DEM operation on each of the even input data samples to produce shuffled even data samples;
- c. a second stage configured to perform a DEM operation on each of the odd input data samples to produce shuffled odd data samples;
- and
- d. a combiner configured to combine in an alternating manner the shuffled even and odd data samples to produce an output data stream.
Dependencies are inferred from the claim text.