Receiver AGC Gain Hold for Pulse Noise Intelligibility
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Solution Overview
Problem
Receivers with IF-AGC function experience deterioration in reception signal quality due to pulse noise, causing intelligibility issues as the gain control mechanism reduces the amplitude of the reception signal, making voices or sounds inaudible.
Innovation Solution
A receiver with a pulse detection circuit that monitors gain changes to detect pulse noise and sets the gain setting value immediately before the noise occurrence as the value after occurrence, maintaining the signal amplitude within a predetermined range, thereby alleviating the gain decrease caused by pulse noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the IF-AGC function controls gain according to pulse noise amplitude, then the pulse noise amplitude is reduced to within a predetermined range, but the reception signal amplitude decreases and intelligibility deteriorates
Solution Approach 1:
The patent applies dynamics by making the AGC operation mode changeable based on detection results. The system dynamically switches between normal AGC operation and a special operation mode where the gain setting value is held constant at the pre-pulse-noise value, preventing unnecessary gain reduction during pulse noise events while maintaining amplitude control stability for actual signal variations.
Solution Approach 2:
The patent changes the parameter behavior by detecting abnormal gain changes (indicative of pulse noise) and adjusting the gain setting value accordingly. When pulse noise is detected, the system sets the gain setting value immediately before the noise occurrence as the value after occurrence, effectively parameter-changing the gain control behavior to preserve reception signal quality.
2Ease of operation
If the gain setting value is automatically adjusted by IF-AGC, then the amplified signal amplitude is maintained within a predetermined range, but pulse noise causes unnecessary gain reduction making voices inaudible
Solution Approach 1:
The patent introduces feedback by having the pulse detection circuit monitor gain setting value changes and provide detection results back to the gain control circuit. This feedback mechanism allows the system to recognize when automatic gain adjustment is caused by pulse noise rather than actual signal variations, enabling intelligent differentiation between legitimate amplitude changes and noise-induced changes.
Solution Approach 2:
The system performs self-service by automatically detecting pulse noise through monitoring gain setting value changes and autonomously adjusting the gain control behavior without external intervention. The receiver itself identifies the problem (abnormal gain changes) and implements the solution (holding gain constant), making the system self-correcting and maintaining voice intelligibility automatically.
3Reliability
If the receiver monitors and responds to all amplitude changes, then amplitude control stability is maintained, but pulse noise events cause unnecessary gain adjustments and silent periods
Solution Approach 1:
The patent applies preliminary action by recording the gain setting value immediately before pulse noise occurrence and using this pre-captured value after the noise event. This preliminary recording allows the system to quickly restore the appropriate gain level without prolonged silent periods, as the correct gain value is already stored and can be immediately reapplied once noise is detected and cleared.
Data Source
AI summary
A receiver and a program capable of, when they have received a pulse noise together with a reception signal, improving quality of the reception signal are provided. A receiver according to present disclosure includes a received-signal amplification circuit configured to amplify a received signal, a gain control circuit configured to set a gain setting value for an AGC operation in the received-signal amplification circuit, the AGC operation being an operation for making an amplitude of an amplified received signal fall within a predetermined range, and a pulse detection circuit configured to monitor a change in the gain setting value and detect whether or not a pulse noise is contained in the received signal based on whether or not the change in the gain setting value meets a predetermined condition.