Pentomics, Inc.

Other

Gateic, Inc.

Arthur Torosyan

Alan Neil Willson, Jr

Dengwei Fu

New hybrid filters are presented based on time and transform domain structures. The hybrid filters have a combined benefit from the advantages obtained by the time and transform domain structures. The overall efficiencies are drawn from combining the pre- and post-processing of the time domain and block based transform domain structures. Further improvements are obtained by interchanging block construction and transforms with linear operations in the pre- and post-processors. The hybrid structures apply to single input, single output, multiple input, and multiple output structures. For the multi input and multi output structures further improvements are obtained by having common processing blocks for the input(s) and common processing blocks for the output(s). They hybrid filters are also efficient in topologies where filter outputs are combined via linear operation(s) generating combined results. The efficiencies of the new hybrid filter may lead to significant fardware, power, silicon area, or somputational savings.

Method and apparatus for hybrid digital filtering

A function generator for a digital system includes a plurality of sub-function generators. Each sub-function generator has an input that receives a respective input value and has an output that provides a respective output value responsive to the respective input value. A case detector receives a system input value and selectively routes at least a first portion of the system input value to the input of at least one selected sub-function generator. The case detector selects the selected sub-function generator in response to at least a second portion of the system input value. The case detector further suppresses transitions of data on the input of at least one non-selected sub-function generator. The case detector further selects the respective output value provided by the at least one selected sub-function generator and provides the selected respective output value as a function generator output value.

Efficient function generator using case detection and output selection

An improved DDFS includes a minority-bit detector to permit a series of cascaded transformation stages to perform half or less than half of the rotational operations otherwise required by detecting whether the required rotation or non-rotation operations are in the minority and performing only the operations in the minority. This substantially reduces the number of minority-select butterfly stages that would otherwise be required. The cascaded transformation stages include a preliminary set of lookup tables in ROM memory, one of which is selected in accordance with the minority-bit detector and may include a subsequent set of butterfly stages providing the inputs to the minority-select butterfly stages.

Method and apparatus for improved direct digital frequency synthesizer

The present invention is embodied in a system for the analysis and design of direct digital synthesizers including a windowing engine, and a method that enables the analysis of DDS output spectra in the presence of phase truncation and arbitrary approximations and errors in the implementation of the sine/cosine mapping function (SCMF) without the need to approximate the DDS characteristics.

System for analysis and design of direct digital frequency synthesizers

An angle rotator uses a coarse stage rotation and a fine stage rotation to rotate an input complex signal in the complex plane according to an angle &#x3b8;. The coarse stage rotation includes a memory device storing pre-computed cosine &#x3b8;and sine &#x3b8;values for fast retrieval, where &#x3b8;is a radian angle that corresponds to a most significant word (MSW) of the input angle &#x3b8;. The fine stage rotation uses one or more error values that compensate for approximations and quantization errors associated with the coarse stage rotation. The rotator consolidates operations into a small number of reduced-size multipliers, enabling efficient multiplier implementations such as Booth encoding, yielding a smaller and faster overall circuit.

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La Crescenta, CA, United States of America

Arthur Torosyan