Multi-Tuner Band Switching With Gradual Impedance Transition
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Solution Overview
Problem
In television receivers with multiple tuners, band changes can cause signal degradation due to insufficient isolation between tuners, leading to spike noise and impedance changes that affect the quality of the broadcast signal when switching between different frequency bands.
Innovation Solution
The implementation of impedance transition correcting circuits, which provide a gradual transition between control states for signal switches, reducing the steepness of impedance changes and minimizing signal degradation across connected tuners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If band changes are performed in multiple tuners, then frequency band selection capability is improved, but signal degradation and spike noise occur due to insufficient isolation between tuners
Solution Approach 1:
The control signal gradually changes the impedance of the signal switch before the actual band change occurs. This preliminary gradual transition prevents abrupt impedance changes that would otherwise cause spike noise and signal degradation in other tuners, while still enabling the desired band selection capability.
Solution Approach 2:
The invention changes the parameter of impedance transition characteristics by controlling the signal switch to gradually change its impedance from an initial value to a final value. This parameter control resolves the contradiction by making the transition smooth rather than abrupt, preventing interference between tuners while maintaining band selection versatility.
2Adaptability or versatility
If signal switches are used for band division, then reception band flexibility is improved, but impedance changes cause signal degradation in other tuners
Solution Approach 1:
The system performs a preliminary gradual impedance transition through controlled signal switch operation before the band change is fully executed. This preliminary action reduces the harmful impedance changes that would otherwise interfere with other tuners, while preserving the flexibility benefits of signal switch-based band division.
Solution Approach 2:
The control signal acts as an intermediary that mediates between the signal switch and the band change operation. By gradually adjusting the impedance through this intermediary control mechanism, the system eliminates abrupt impedance changes and their harmful interference effects while maintaining the desired band selection flexibility.
3Speed
If rapid band switching is implemented, then channel changing speed is improved, but spike noise and signal degradation increase
Solution Approach 1:
The invention changes the temporal parameter of the switching operation by implementing gradual impedance transition instead of instantaneous switching. This parameter modification reduces spike noise while the overall band change is still completed efficiently, resolving the contradiction between switching speed and noise generation.
Solution Approach 2:
The system transitions from static abrupt switching to dynamic gradual impedance change. By making the switching process dynamic and continuous rather than instantaneous, the system reduces harmful spike noise while maintaining practical channel changing speed through optimized control signal timing.
Data Source
AI summary
A signal processing device and signal processing method. A plurality of tuner circuits includes at least one that selectively provides a signal from among a plurality of signal bands potentially in an input signal in response to a control signal having a transition between a first state and a second state. A correction circuit corresponds to at least one of the plurality of tuner circuits, and is configured to receive the control signal and provide a corrected control signal for the tuner circuit. The corrected control signal has a gradual transition between the first state and the second state as compared to the transition between the first state and the second state in the control signal.