Quarter-Rate Digital Upconverter With Half-Sample Interpolation
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Solution Overview
Problem
Digital upconversion in communication systems is processing-intensive, limited by sampling rate, requiring high-speed digital signal processors and increased processing components, which can restrict bandwidth and data rate.
Innovation Solution
The method involves filtering one stream of complex samples to form a half-sample interpolated stream and delaying the other stream by the group delay of the filter plus half a sample, followed by quarter-rate upconversion to achieve efficient digital upconversion, reducing processing requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If higher sample rates are used to process higher bandwidth signals, then bandwidth increases, but processing requirements and system complexity increase
Solution Approach 1:
The patent segments the complex upconversion process into separate in-phase and quadrature component processing. By treating the complex signal as two independent real signals that can be processed separately, the computational complexity is reduced while maintaining the ability to handle high bandwidth signals.
Solution Approach 2:
The patent inverts the conventional approach by performing upconversion on the complex baseband signal before conversion to real passband, rather than converting to real first and then upconverting. This allows the use of efficient complex arithmetic operations that reduce processing requirements.
2Productivity
If faster digital signal processors and increased processing components are used, then processing speed improves, but device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates redundant computational operations in the upconversion process. By identifying and removing unnecessary calculations and multiplications, the system achieves faster processing with fewer processing components.
Solution Approach 2:
The patent changes the mathematical parameters and representation of the signal processing operations. By using complex baseband representation and optimizing the arithmetic operations, the processing speed improves without requiring additional hardware components.
3Reliability
If conventional digital upconversion methods are used, then upconversion functionality is achieved, but processing complexity and computational load increase
Solution Approach 1:
The patent merges the filtering and upconversion operations into a unified process. By combining these functions and optimizing their interaction, the processing complexity is reduced while maintaining reliable upconversion functionality.
Solution Approach 2:
The patent performs preliminary filtering of the complex baseband signal before the upconversion operation. This preliminary action simplifies subsequent processing steps and reduces the overall computational load while ensuring functional correctness.
Data Source
AI summary
Techniques for efficient upconversion can process complex input data, such as for example data in an inphase and quadrature form. Half sample interpolation filtering and delay can be performed, and the results can be combined in a quarter-rate upconverter. The quarter rate upconversion can allow one of the half-sample interpolating filtering and the delay to be performed on one of either the inphase and quadrature samples.