Joint Noise Shaping for Quantized Signal Parameters
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Solution Overview
Problem
Conventional noise shaping methods for quantized parameters in digital signal processing fail to achieve desired spectral properties when multiple parameters contribute to the generation of an output signal, particularly in wireless transceivers, leading to undesirable noise behavior in RF or baseband signals.
Innovation Solution
A method for determining a noise-shaped quantized parameter that considers the quantization of one parameter and a further parameter contributing to the output signal, using error estimation and selection criteria to optimize noise shaping, thereby maintaining low noise energy at a notch frequency and improving signal characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional noise shaping methods are applied independently to each quantized parameter, then the individual spectral behavior of each parameter is satisfactory, but the resultant output signal does not achieve desired spectral properties
Solution Approach 1:
The patent merges the noise shaping processes of multiple quantized parameters into a unified joint noise shaping approach. Instead of independently shaping noise for each parameter (I and Q components), the system jointly shapes the noise across all parameters contributing to the output signal, ensuring the composite spectral properties meet desired specifications.
Solution Approach 2:
The patent implements feedback by calculating the actual error energy in the output signal resulting from quantization and using this information to adjust the noise shaping filter coefficients. The system iteratively optimizes the joint noise shaping filters based on the observed spectral characteristics and error energy, enabling adaptive optimization of the overall output signal quality.
2Device complexity
If word length of digital signal is reduced for implementation reasons, then device complexity is reduced, but quantization error increases
Solution Approach 1:
The patent changes the spectral distribution parameters of quantization error through noise shaping filters. By modifying the transfer functions of the noise shaping filters, the system redistributes quantization error energy from in-band frequencies to out-of-band frequencies, effectively reducing in-band error energy even with reduced word length.
Solution Approach 2:
The patent converts the harmful quantization error into a beneficial shaped noise spectrum. Instead of treating quantization error as unwanted distortion, the system uses noise shaping filters to deliberately shape the error spectrum, pushing error energy to frequency regions where it causes minimal degradation to the desired signal.
3Ease of manufacture
If quantization is applied to steering values, then implementation feasibility is improved, but error energy in frequency range of interest increases
Solution Approach 1:
The patent applies local quality by implementing noise shaping that specifically targets the frequency range of interest. The noise shaping filters are designed with transfer functions that selectively push error energy away from the frequency band containing the desired signal, while allowing other frequency regions to contain the shaped noise.
Data Source
AI summary
A method for determining a noise shaped quantized parameter contributing to generation of an output signal comprises estimating an error within the output signal using a quantization of the parameter and a quantization of a further parameter contributing to generation of the output signal. The quantization of the parameter is used as the noise shaped quantized parameter according to a selection criterion.