LNA Gain Timing Control to Prevent Broadcast Reception Dropouts
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Solution Overview
Problem
Existing gain control methods for low noise amplifiers (LNAs) in broadcast receivers cause noise-induced screen or sound disconnections due to gain discontinuities during automatic gain control (AGC), affecting the reception of broadcast signals.
Innovation Solution
A method and device that adjust LNA gain based on power measurement values, avoiding control during service channel periods by parsing fast information channels to determine service channel periods and controlling gain only outside these periods, using a timing selector to prevent noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LNA gain control is performed continuously based on power detector values, then saturation is avoided and overall gain is maintained uniform, but gain discontinuity occurs causing noise that leads to screen or sound disconnection
Solution Approach 1:
The patent implements periodic gain control by detecting service channel periods through FIC parsing and disabling AGC during these periods. The system alternates between AGC-active periods (for signal saturation avoidance) and AGC-disabled periods (for noise prevention during service channels), creating a periodic control pattern that resolves the contradiction between continuous gain control benefits and discontinuity noise harm.
Solution Approach 2:
The patent introduces an intermediary mechanism using the FIC (Fast Information Channel) as a mediator to detect service channel periods. This intermediary detection system enables the AGC controller to identify when to pause gain control operations, thereby preventing noise during service channels while maintaining saturation avoidance during other periods.
2Stability of the object's composition
If AGC control is activated to maintain uniform gain, then signal strength is stabilized, but instantaneous gain change of 15 dB causes reception screen or sound disconnection
Solution Approach 1:
The system implements periodic AGC operation by pausing gain control during service channel periods detected through FIC parsing. This periodic activation pattern allows the system to maintain signal strength stability during non-service periods while preventing instantaneous gain changes during service channels, thereby avoiding reception screen or sound disconnection.
Solution Approach 2:
The patent applies preliminary action by detecting service channel periods in advance through FIC parsing before the actual service channel transmission begins. This advance detection allows the AGC system to preemptively pause gain control operations, preventing noise-induced disconnection before it occurs.
Data Source
AI summary
A low noise amplifier (LNA) gain control method and a broadcast receiving device performing the same are disclosed. The method includes determining a LNA gain control based on a power measurement value of a received broadcast signal, confirming whether the received broadcast signal corresponds to a service channel period, stopping the LNA gain control when the received broadcast signal corresponds to the service channel period, and performing the LNA gain control when the received broadcast signal does not correspond to the service channel period.