Receiver Gain Compensation for Fast Settling Digital Filtering
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Solution Overview
Problem
In high-speed packet communication, the preamble occupies a large portion of the overhead, leading to elongated gain settling time due to transient signals, which hinders rapid gain control and delays digital signal processing.
Innovation Solution
A receiver structure and method that includes a programmable gain amplifier, ADC, digital filter, received power estimator, and gain controller, with a digital filter configured to substitute gain-compensated values for predetermined delay times, and a transient signal compensator to minimize transient signal periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If closed loop gain control is used to maintain signal quality, then reception performance is improved, but gain settling time is elongated due to transient signals
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing compensation values in a lookup table before transient signals occur. The compensation values are prepared in advance based on expected gain adjustments, allowing the system to quickly retrieve and apply the appropriate compensation without waiting for transient signals to develop and be measured in real-time.
Solution Approach 2:
The patent introduces an intermediary compensation signal that mediates between the gain control adjustment and the digital filter processing. This compensation signal is added to the transient signal to cancel it out, allowing the gain control to proceed rapidly while maintaining signal quality. The intermediary compensation acts as a bridge that resolves the conflict between speed and accuracy.
2Speed
If transient signal compensation is applied to reduce settling time, then gain control speed is improved, but device complexity increases
Solution Approach 1:
The patent uses copying by creating a compensation signal that replicates the characteristics of the transient signal but with opposite polarity. Instead of directly manipulating the complex transient signal, the system generates a simplified copy that can be easily added to cancel the transient effect. This copying approach simplifies the compensation mechanism while achieving the desired speed improvement.
Solution Approach 2:
The patent applies parameter changes by modifying the gain control parameters to include pre-calculated compensation values. Rather than changing the fundamental operation of the gain control, the system adjusts the parameters (compensation values stored in lookup tables) to enable faster settling. This parameter-based approach improves speed without significantly increasing device complexity.
3Measurement precision
If digital filter uses past values for processing, then filtering accuracy is improved, but transient signals cause performance degradation
Solution Approach 1:
The patent converts the harmful transient signal into a beneficial compensation opportunity. By detecting the transient signal caused by gain adjustments, the system generates a compensation value that, when added to the transient signal, eliminates its harmful effects. The transient signal that initially degrades performance is transformed into a trigger for compensation, ultimately improving filtering accuracy and reception performance.
Solution Approach 2:
The patent applies preliminary anti-action by pre-calculating compensation values that counteract the expected transient signals before they degrade filter performance. The lookup table stores compensation values that are applied in advance or at the moment of transient occurrence, preventing the transient signal from causing performance degradation in the first place.
Data Source
AI summary
Embodiments of the present general inventive concept relate to a transient signal compensator for apparatuses such as a transceiver or receiver used in a wire/wireless communication and/or a digital signal processor that may be used in the receiver and methods thereof. In one embodiment, a receiver can include an amplifier to amplify a received signal, a digital filter to filter a digital signal corresponding to an output signal of the amplifier, where the digital filter is configured to replace a corresponding value (e.g., stored in a memory) for the digital filter with a gain compensated value during a predetermined delay time after a gain of the amplifier is changed (e.g., from a first gain g1 to a different second gain g2). The gain compensated value to compensate for a transient signal (e.g., related to the change from the first gain g1 to the second gain g2).