Signal Generation Apparatus Using Serial-Parallel Conversion and Convolution
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Solution Overview
Problem
Conventional signal generation devices face issues with signal quality deterioration due to frequency ripples and increased peak-to-average power ratio (PAPR) caused by steep cutouts in the frequency domain during signal division.
Innovation Solution
A signal generation device comprising a digital signal processing unit that performs serial-parallel conversion, convolution arithmetic operations, and addition to generate divided signals, which are then converted to analog signals by DACs and interleaved by an analog multiplexer to produce a broadband signal with high quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If steep cutout in frequency domain is used to divide input signal, then signal division is achieved, but frequency ripples and increased PAPR occur causing signal quality deterioration
Solution Approach 1:
The input signal is divided into multiple frequency bands (low frequency and high frequency components) using band division units. Each band is processed separately through spectrum folding and filtering operations, allowing independent optimization of each segment to avoid the PAPR and ripple issues that would affect the entire signal if processed as a single steep cutout operation.
Solution Approach 2:
A filter is introduced as an intermediary component between the spectrum folding unit and the DAC. This filter smooths the transition between frequency bands, eliminating the steep cutout effect that causes frequency ripples and PAPR increase, while still achieving effective signal division through the combined band division and filtering process.
2Productivity
If multiple DACs and analog multiplexer are used to generate broadband signal, then signal capacity is increased, but system complexity increases
Solution Approach 1:
The signal generation system is segmented into multiple parallel processing channels, each handling a specific frequency band. Multiple DACs convert digital signals to analog in parallel, and an analog multiplexer combines these parallel outputs into a single broadband signal. This segmentation allows high signal capacity through parallel processing while managing complexity by organizing functions into modular, independent units.
Solution Approach 2:
The analog multiplexer serves multiple functions: it combines outputs from multiple DACs, performs signal interleaving to achieve broadband output, and synchronizes the parallel processed signals. This multi-functionality increases signal capacity while minimizing the increase in system complexity by having a single component perform multiple critical operations.
3Measurement precision
If band division and spectrum folding are performed, then frequency domain processing is achieved, but frequency ripples are generated
Solution Approach 1:
The frequency domain processing is segmented into band division and spectrum folding operations that create gentle transitions between frequency bands. By dividing the signal into multiple bands with overlapping or adjacent frequency ranges and processing them separately, the system achieves precise frequency domain control without the abrupt cutoffs that generate frequency ripples.
Solution Approach 2:
A filter is used as an intermediary between spectrum folding and the DAC to smooth the frequency transitions. This filter eliminates the frequency ripples generated by the band division and spectrum folding operations, maintaining the precision of frequency domain control while removing the harmful ripple effects from the final signal.
Data Source
AI summary
A signal generation device that includes a digital signal processing unit, a plurality of digital-analog conversion units that respectively converts a plurality of digital signals output from the digital signal processing unit into analog signals, and an analog multiplexer that interleaves the analog signals respectively output from the plurality of digital-analog conversion units to generate a broadband signal, in which the digital signal processing unit includes a serial-parallel conversion unit that divides an input signal into a number according to a ratio between a sampling frequency of the plurality of digital-analog conversion units and a clock frequency of the analog multiplexer in a time domain to generate a plurality of divided signals, and a plurality of convolution arithmetic operation units that receives the plurality of divided signals generated by the serial-parallel conversion unit as inputs and generates a plurality of digital signals corresponding to the respective digital-analog conversion units.