Origin-Avoiding Circuit for LINC Amplifier Ringing Suppression
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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, reducing efficiency.
Innovation Solution
An origin avoiding circuit is introduced upstream of the LINC type linear amplifier to modify input signals sampled near the origin, preventing ringing by replacing sampled values with fixed values based on the complex plane quadrant, thereby ensuring constant amplitude signals are maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low pass filters are used to limit high-frequency components in constant amplitude signals, then signal quality is improved, but ringing occurs causing amplitude variations that prevent continuous saturated operation
Solution Approach 1:
The origin avoiding circuit performs preliminary action by detecting signals near the origin before they pass through the low pass filter and replaces them with fixed values. This prevents the generation of ringing in the first place, rather than attempting to remove it afterward. The circuit calculates replacement values based on historical data and quadrant information, ensuring that the signal maintains constant amplitude characteristics before entering the filtering stage.
Solution Approach 2:
The origin avoiding circuit applies preliminary anti-action by preemptively counteracting the condition that causes ringing. By detecting when the signal approaches the origin (where phase changes cause ringing) and replacing those samples with predetermined fixed values, the circuit prevents the harmful amplitude variations from occurring. This is done by anticipating the problem before it manifests in the filtered output.
2Adaptability or versatility
If signals near the origin are sampled, then signal coverage is improved, but phase changes cause ringing that disrupts saturated operation
Solution Approach 1:
The origin avoiding circuit converts the harmful effect of origin sampling into a benefit by using the detected origin conditions to trigger a replacement mechanism. When the circuit detects that a signal is near the origin (where phase changes would cause ringing), it replaces that sample with a fixed value calculated from historical data. This transforms the problematic origin samples into controlled replacement values that maintain constant amplitude, thereby converting a source of ringing into a mechanism for ensuring signal stability.
3Use of energy by moving object
If nonlinear amplifiers operate in saturated state, then power efficiency is improved, but ringing causes amplitude variations that prevent continuous operation
Solution Approach 1:
The origin avoiding circuit ensures continuous saturated operation by performing preliminary action to prevent ringing before it occurs. By replacing origin-proximity samples with fixed values based on historical data and quadrant information, the circuit ensures that the signal maintains constant amplitude characteristics. This allows nonlinear amplifiers to operate continuously in their efficient saturated state without being disrupted by amplitude variations caused by ringing.
Data Source
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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.