Joint DSA-VVA Gain Control for Step Attenuation Spikes
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Solution Overview
Problem
Current communication receiver systems face challenges in handling a wide dynamic range of signal strengths due to limited dynamic range capabilities of detectors and the introduction of distortion by variable voltage attenuators, which can lead to power spikes and disruptions in demodulation and error correction processes.
Innovation Solution
Implementing a coordinated control system using a digital step attenuator (DSA) and a variable voltage attenuator (VVA) to manage signal attenuation, where the DSA attenuates signals in discrete steps and the VVA provides fine adjustments to prevent power spikes, ensuring smooth gain control across the dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable voltage attenuator (VVA) is used to handle wide dynamic range, then the dynamic range capability is improved, but signal distortion occurs especially at the margins of the dynamic range
Solution Approach 1:
The gain control function is segmented into two independent attenuators: a step attenuator (DSA) that handles coarse attenuation in discrete steps, and a variable voltage attenuator (VVA) that handles fine continuous adjustments. This segmentation allows each component to operate within its optimal range, reducing overall distortion while maintaining wide dynamic range capability.
Solution Approach 2:
The patent combines two different attenuator technologies (step attenuator and variable voltage attenuator) into a unified gain control system. The step attenuator provides the bulk of the attenuation range, while the VVA provides smooth fine-tuning, merging their strengths to achieve both wide dynamic range and low distortion.
2Adaptability or versatility
If a step attenuator is used to provide coarse attenuation, then the dynamic range is improved, but power spikes occur due to discrete steps in attenuation
Solution Approach 1:
The variable voltage attenuator is configured to preemptively adjust its attenuation level in response to predicted signal strength changes before the step attenuator switches between discrete steps. This preliminary action smooths out the transitions and prevents power spikes from occurring.
Solution Approach 2:
The variable voltage attenuator acts as an intermediary between the input signal and the step attenuator, absorbing the discontinuities caused by the step attenuator's discrete switching. It provides a buffering effect that smooths the overall gain control output.
3Adaptability or versatility
If a high dynamic range variable voltage attenuator is used, then the dynamic range is improved, but the cost increases and frequency bandwidth is limited
Solution Approach 1:
The attenuation function is segmented between a step attenuator that provides the majority of the dynamic range (handling coarse adjustments), and a variable voltage attenuator that provides fine continuous control. This segmentation allows the use of a more limited-range VVA, reducing cost and bandwidth constraints while achieving overall high dynamic range performance.
Solution Approach 2:
Instead of using a single VVA with full dynamic range capability, the patent uses a step attenuator to handle the partial (coarse) attenuation needs, allowing the VVA to operate only in a limited fine-adjustment range. This partial action approach reduces the requirements for the VVA, lowering cost and improving bandwidth.
Data Source
AI summary
Signal processing to compensate for gain control output spikes caused by steps in a digital step attenuator. A method includes receiving a changing power input signal at a receiver. The method includes determining that a change in power of the input signal will cause a step attenuator to change its attenuation in a step of a predetermined amount. The method further includes based on determining that the change in power of the input signal will cause a digital step attenuator to change its attenuation in a step of a predetermined amount, causing a variable attenuator to change its attenuation by an amount related to the predetermined amount at a time coinciding with a time when the step attenuator changes its attenuation by the predetermined amount. The method further includes outputting a gain-controlled output signal resulting from applying the step attenuator and the variable attenuator to the changing power input signal.