Receiver Gain Monitoring for Pulse Noise Suppression
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Solution Overview
Problem
Receivers with IF-AGC function deteriorate the quality of reception signals when they receive pulse noise, causing the amplitude of smaller signals to decrease and leading to inaudible voices or sounds.
Innovation Solution
A receiver with a received-signal amplification circuit, gain control circuit, pulse detection circuit, and pulse noise removal circuit that sets a gain setting value to maintain signal amplitude within a range, detects pulse noise based on gain changes, and attenuates the signal only during the detection of pulse noise to prevent intelligibility loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the receiver uses IF-AGC function to control gain automatically, then the amplitude control of received signals is improved, but the intelligibility of reception signals deteriorates when pulse noise is present
Solution Approach 1:
The received signal is divided into two paths: a main path for normal AGC processing and a monitoring path for pulse noise detection. The monitoring path extracts a monitoring signal from the received signal to independently detect pulse noise, allowing the system to differentiate between normal signal variations and pulse noise events.
Solution Approach 2:
A monitoring signal acts as an intermediary between the received signal and the pulse noise detection mechanism. This monitoring signal is derived from the received signal but processed separately to detect pulse noise characteristics without affecting the main AGC control loop.
2Object-affected harmful factors
If the receiver attenuates the signal to reduce pulse noise impact, then the harmful effect of pulse noise is reduced, but the amplitude of the reception signal decreases causing voices to become inaudible
Solution Approach 1:
The pulse noise removal circuit applies attenuation periodically only during detected pulse noise events rather than continuously. The attenuation is activated when pulse noise is detected and deactivated when normal signal conditions prevail, creating a periodic on-off action that removes noise while preserving signal.
Solution Approach 2:
The system performs preliminary detection of pulse noise using the monitoring signal and gain setting value changes before applying attenuation to the main received signal. This preliminary detection allows the system to prepare and apply attenuation only when necessary, preventing unnecessary signal loss.
3Stability of the object's composition
If the receiver maintains constant gain for AGC operation, then the amplitude stability of received signals is improved, but the ability to detect and remove pulse noise deteriorates
Solution Approach 1:
The signal processing is segmented into independent monitoring and main processing paths. The monitoring path specifically tracks gain setting value changes to detect pulse noise, while the main path maintains stable AGC operation. This segmentation allows the system to detect pulse noise through gain variations without compromising overall amplitude stability.
Solution Approach 2:
The system uses feedback from the monitoring signal and gain setting value changes to detect pulse noise events. The monitoring path continuously monitors the received signal and provides feedback about gain variations, enabling the system to identify pulse noise while maintaining stable AGC control in the main path.
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 the present disclosure includes a received-signal amplification circuit configured to amplify a monitoring received signal branched from 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 monitoring received signal fall within a predetermined range, 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.