Multi-Sub-DAC Signal Generation With Folded-Signal Compensation
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Solution Overview
Problem
Current signal generating devices using multiple sub DACs face challenges in compensating for individual differences and signal degradation due to incomplete analog devices, particularly when up-converting baseband output signals, leading to suboptimal broadband signal generation.
Innovation Solution
A signal generating device is designed with a digital signal processing unit that includes a 2M×M filter capable of independent response function settings for each input and output combination, using M sub DACs to generate a broadband signal by down-converting and folding signals, and employing an IQ modulator circuit or analog multiplexer to achieve precise compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple sub DACs are used to generate broadband signals, then the signal bandwidth is improved, but the individual differences between sub DACs cause signal degradation
Solution Approach 1:
The patent divides the broadband signal generation into multiple sub-DAC channels, each handling a portion of the total bandwidth. By segmenting the signal processing across multiple devices, the system achieves broader bandwidth while managing individual device limitations through parallel processing of signal portions.
Solution Approach 2:
The patent implements a feedback mechanism where the output signals from multiple sub-DACs are combined and processed through a combiner and filter. The system uses the combined signal to adjust and compensate for individual differences between sub-DACs, ensuring consistent signal quality across the broadband output.
2Reliability
If conventional compensation methods are used for sub DAC individual differences, then some signal degradation is corrected, but the computational load increases and compensation is incomplete
Solution Approach 1:
The patent performs preliminary compensation by processing each sub-DAC output individually through dedicated filters before combination. This preliminary action addresses individual differences at an early stage, reducing the computational burden on subsequent processing while achieving more complete compensation than conventional methods.
Solution Approach 2:
The patent merges the compensated outputs from multiple sub-DACs through a combiner circuit. By combining the individually compensated signals, the system achieves complete compensation效果 while distributing the computational load across parallel processing paths rather than requiring intensive centralized computation.
3Speed
If analog devices are used for up-conversion, then broadband signal generation is achieved, but incompleteness of analog devices causes signal degradation
Solution Approach 1:
The patent introduces digital signal processing elements as intermediaries between the analog sub-DACs and the final output. Digital filters and processing stages compensate for analog device imperfections, acting as a mediator that corrects signal degradation caused by analog incompleteness while preserving the broadband capabilities.
Solution Approach 2:
The patent replaces purely analog up-conversion and signal processing with a hybrid approach that uses digital signal processing for compensation and filtering. This substitution of digital processing for analog operations corrects signal fidelity issues while maintaining the broadband signal generation capability.
Data Source
AI summary
A signal generating device includes a digital signal processing unit, M sub DACs of which an analog bandwidth is fB, M being an integer equal to or greater than 2, a broadband analog signal generating unit configured to generate a broadband analog signal that includes a component of a frequency of (M-1)fB or more by using M analog signals output from the M sub DACs. The digital signal processing unit includes components for generating M original divided signals that correspond to signals obtained by dividing a desired output signal into M portions on a frequency axis and down-converting the portions to the baseband, components for generating M folded divided signals by folding back the M original divided signals on the frequency axis, and a 2M×M filter that takes the original divided signals and the folded divided signals as inputs and outputs M composite signals to be transmitted to the M sub DACs. The 2M×M filter can set a response function independently for each of 2M2 combinations of input and output.