Multi-Threshold Receiver Circuit for Feedforward Gain Calibration
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Solution Overview
Problem
Existing receiver circuits face challenges in achieving fast and efficient automatic gain control, particularly in high dynamic range applications, where stability constraints and the need for auxiliary calibration circuits or programmable gain amplifiers can limit performance.
Innovation Solution
A receiver circuit with multiple sub-receivers that compare input-signalling with different weighted threshold values, allowing for fast feed-forward automatic gain calibration by identifying the most significant triggered sub-receiver and configuring the circuit for subsequent signal processing, thereby eliminating the need for large circuit overhead or auxiliary calibration circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional feedback-based automatic gain control is used, then gain stability is improved, but calibration speed deteriorates due to loop settling time requirements
Solution Approach 1:
The patent inverts the traditional feedback-based AGC approach by implementing a feedforward calibration mechanism. Instead of using feedback loops that require settling time, the system uses multiple sub-receivers with different threshold values to determine the appropriate gain setting in advance, before the actual signal processing begins. This inversion of the control direction eliminates loop stability constraints and achieves instant calibration.
Solution Approach 2:
The patent performs gain calibration in advance by having multiple sub-receivers ready with different threshold values. During calibration mode, the system determines which sub-receiver threshold is appropriate for the current signal conditions before actual signal processing. This preliminary determination of gain settings eliminates the need for slow feedback adjustment during operational mode.
2Speed
If auxiliary calibration circuits or programmable gain amplifiers are added to achieve fast calibration, then calibration speed is improved, but device complexity increases
Solution Approach 1:
The patent makes the sub-receivers multi-functional by having them serve dual purposes: they perform the calibration function by comparing signals with different thresholds, and they also serve as the operational receivers for actual signal processing. This eliminates the need for separate auxiliary calibration circuits because the calibration function is integrated into the existing receiver structure.
Solution Approach 2:
The patent merges the calibration circuitry with the signal processing circuitry by using the same sub-receivers for both calibration and operational modes. The comparators and amplifiers are reused across different functions, eliminating redundant components and reducing overall device complexity while maintaining fast calibration capability.
3Measurement precision
If multiple sub-receivers with different threshold values are used for feedforward calibration, then calibration accuracy is improved, but power consumption increases due to all sub-receivers being active
Solution Approach 1:
The patent segments the receiver functionality into multiple sub-receivers, each handling a specific signal range or condition. By dividing the overall reception task into segments with different threshold values, the system can accurately handle diverse signal conditions while only activating the necessary sub-receiver segments during operation, thereby reducing overall power consumption.
Solution Approach 2:
The patent implements dynamic switching between different sub-receivers based on signal conditions. During calibration mode, all sub-receivers are active to determine the appropriate threshold, but during operational mode, only the selected sub-receiver with the matching threshold is activated. This dynamic activation strategy maintains calibration accuracy while minimizing power consumption by keeping only necessary components active.
Data Source
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AI summary
A receiver circuit, comprising: an receiver-input-terminal configured to receive input-signalling; an receiver-output-terminal configured to provide output-signalling; a plurality of sub-receivers, each configured to compare the received input-signalling with a different effective threshold value in order to provide a digital sub-receiver-output-signal, wherein the different effective threshold values have weighted values in a sequence between a least significant value and a most significant value; a controller configured to, in response to detecting calibration-signalling at the receiver-input-terminal: process the digital sub-receiver-output-signals in order to identify the sub-receiver with the most significant effective threshold value that is triggered by the calibration-signalling as a triggered-sub-receiver; identify a preceding-sub-receiver as the sub-receiver that has an effective threshold value that is before that of the triggered-sub-receiver in the sequence of weighted effective threshold values; and configure the receiver circuit such that, for subsequent signal processing, the sub-receiver-output-signal from the preceding-sub-receiver is provided to the receiver-output-terminal.