Parallel Mixing-Mode DAC for Sampling Image Attenuation
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Solution Overview
Problem
Current digital-to-analog conversion systems in wireless communication networks face challenges in attenuating image signals around multiple harmonics of the sampling frequency, which can lead to increased power consumption and silicon area, especially when using interleaving DACs to cancel these signals.
Innovation Solution
A system that includes a main DAC and a mixing-mode DAC operating in parallel, where the mixing-mode DAC frequency-mixes a replica of the input signal to cancel image signals by combining outputs through a combiner, allowing for reduced power consumption and smaller footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If interleaving DACs are used to cancel image signals, then image signal attenuation is improved, but power consumption and silicon area increase
Solution Approach 1:
The patent divides the single high-speed DAC function into two parallel DACs operating at lower speeds. The first DAC operates at the base sampling rate while the second DAC operates at a multiple of the sampling rate, with its output mixed and combined to cancel image signals. This segmentation allows image attenuation without requiring a single high-performance interleaved DAC, reducing overall power consumption and silicon area.
Solution Approach 2:
The patent introduces a mixer as an intermediary component between the second DAC and the combiner. The mixer frequency-translates the output of the second DAC to align it with the first DAC's output spectrum, enabling constructive combination that attenuates image signals. This intermediary approach provides a more power-efficient alternative to direct interleaving while achieving the desired image rejection.
2Object-generated harmful factors
If interleaving DACs are used to cancel image signals, then image signal attenuation is improved, but silicon area increases
Solution Approach 1:
The patent segments the high-speed conversion task across two parallel DAC paths with different sampling rates. By using a second DAC operating at a multiple of the base rate and mixing its output, the system achieves image signal cancellation without requiring a single large-scale high-speed DAC, thereby reducing total silicon area.
Solution Approach 2:
The patent changes the operating parameters of the parallel DACs, specifically using different sampling rates (one at the base rate and another at a multiple of the base rate). This parameter differentiation allows the system to achieve image attenuation through spectral manipulation rather than requiring identical high-speed interleaved DACs, reducing the total silicon area required.
3Object-generated harmful factors
If conventional interleaving DAC methods are used, then image signals are attenuated, but high-speed performance is compromised by increased complexity
Solution Approach 1:
The patent uses a mixer as an intermediary to frequency-translate the second DAC's output, simplifying the combination process. This approach avoids the complexity of directly interleaving high-speed DAC outputs while achieving image attenuation through controlled spectral manipulation, reducing overall system complexity.
Solution Approach 2:
By changing the sampling rate parameter of the second DAC to a multiple of the base rate and using frequency mixing, the patent achieves image attenuation with a simpler system architecture compared to conventional interleaving methods that require precise synchronization and matching of high-speed DAC channels.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively attenuates image signals while maintaining high-speed performance, reducing power consumption and silicon area compared to conventional interleaving DAC methods.
Implementation Method 1
frequency mixing the second analog signal to generate a frequency-mixed analog signal
Data Source
AI summary
Certain aspects of the present disclosure generally relate to circuitry and techniques for digital-to-analog conversion. One example system for digital-to-analog conversion generally includes a first digital-to-analog converter (DAC) having an input coupled to an input node of the system and a mixing-mode DAC having an input coupled to an input node of the system. The mixing-mode DAC may include a second DAC and a mixer, an output of the second DAC being coupled to an input of the mixer. The system may also include a combiner, wherein an output of the first DAC is coupled to a first input of the combiner, and wherein an output of the mixer is coupled to a second input of the combiner.