Origin-Avoiding Circuit for Ringing Control in LINC Amplifiers
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Solution Overview
Problem
Ringing in the signal after passing through low pass filters in LINC type linear amplifiers disrupts the continuous saturated operation of nonlinear amplifiers, leading to inefficiency.
Innovation Solution
An origin avoiding circuit is introduced upstream of the linear amplifier, which samples the input signal and modifies its value when near the origin, replacing it with a fixed value to prevent ringing by using a comparator and modification circuit to determine the quadrant on the complex plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low pass filters are used to remove high-frequency components in LINC type linear amplifiers, then signal filtering is improved, but ringing occurs in the output signal
Solution Approach 1:
The origin avoiding circuit performs preliminary action by detecting and modifying input signals near the origin before they pass through the low pass filter. By replacing origin-near samples with fixed values in advance, the circuit prevents the generation of ringing that would otherwise occur during filtering, thus eliminating the harmful effect before it manifests in the filtered output.
2Reliability
If ringing occurs in the signal after low pass filtering, then signal purity is improved, but nonlinear amplifier cannot operate continuously in saturated state
Solution Approach 1:
The origin avoiding circuit performs preliminary modification of the input signal by detecting samples near the origin and replacing them with fixed values before the signal enters the low pass filter and nonlinear amplifier chain. This advance correction ensures that the signal maintains proper amplitude characteristics throughout processing, enabling nonlinear amplifiers to operate continuously in their efficient saturated state while preserving signal purity.
3Object-generated harmful factors
If origin avoiding circuit modifies sampled values near origin, then ringing is reduced, but device complexity increases
Solution Approach 1:
The origin avoiding circuit acts as an intermediary component positioned between the signal source and the low pass filter. It includes a comparator that detects origin-near samples and a modification circuit that replaces these samples with fixed values. This intermediary structure effectively reduces ringing by correcting problematic signal samples before they undergo filtering, while adding only moderate complexity through the use of standard comparator and modification circuit components.
Data Source
AI summary
Ringing of a signal after passing through a low pass filter in an LINC type linear amplifier is remedied. A linear amplifying device includes the linear amplifier including the low pass filter for removing high-frequency components; and an origin avoiding circuit which receives an original input signal and is provided upstream of the linear amplifier. If the original input signal is sampled in the vicinity of an origin, the origin avoiding circuit modifies a sampled value so at to replace the sampled value with a fixed value, and supplies the modified input signal to the linear amplifier.