Channel Gain Switching Timing for Low-Noise Image Signals
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Solution Overview
Problem
The variation in picture signal levels due to load changes in the processing circuit when gain values are switched causes interference between channels, particularly affecting infrared light signals with low sensitivity, leading to increased noise influence.
Innovation Solution
A gain modification device with a gain reflection control unit that adjusts the timing of gain value switching for different channels, delaying or disabling gain value updates to minimize load changes and reduce signal level variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gain value is increased to amplify weak infrared signals, then the signal level is improved, but the noise influence from load changes increases
Solution Approach 1:
The gain control is segmented into two independent parts: a first gain control unit that operates independently of channel switching, and a second gain control unit that is activated only when needed. This segmentation allows the system to maintain stable baseline gain while applying additional gain only when required, reducing noise from simultaneous switching operations.
Solution Approach 2:
The first gain control unit establishes the baseline gain setting in advance, before any channel switching occurs. This preliminary action ensures that the gain is already optimized for the signal level, preventing the need for subsequent gain adjustments that would cause load changes and noise during switching.
2Speed
If gain values are switched simultaneously across all channels, then the processing speed is improved, but the signal level variation due to load change increases
Solution Approach 1:
The gain control operations are segmented into two distinct units with different activation conditions. The first gain control unit operates continuously and independently, while the second unit operates selectively. This segmentation allows the system to maintain processing speed through the first unit while the second unit provides stability by being activated only when additional gain adjustment is necessary.
Solution Approach 2:
The system dynamically adjusts the operation of the second gain control unit based on the specific channel being switched. The second unit is activated only when a channel requires gain adjustment, and its operation is coordinated with the channel switching timing. This dynamic approach maintains processing speed while minimizing signal level variations.
3Measurement precision
If the gain value is increased for infrared channels, then the signal detection capability is improved, but the interference with other channels increases
Solution Approach 1:
The gain control is segmented into channel-independent first gain control and channel-specific second gain control. This segmentation allows infrared channels to receive the necessary gain boost for improved detection capability while the second unit is carefully controlled to minimize interference with other channels through coordinated switching.
Solution Approach 2:
The second gain control unit acts as an intermediary that is selectively activated only when channel switching requires additional gain adjustment. This intermediary approach allows the system to provide enhanced signal detection for infrared channels while preventing unnecessary gain changes that would cause interference with other channels during normal operation.
Data Source
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AI summary
A gain modification device (20) includes a plurality of gain modification units (31) whose number of units corresponds to a number of kinds of a plurality of signals input to the plurality of gain modification units, each one of the plurality of gain modification units (31) being configured to modify a gain value used to amplify the plurality of signals, and a plurality of gain reflection control units (44) configured to change a timing at which the gain value is to be switched by the plurality of gain modification units (31) such that the gain value of one of the plurality of signals affecting a signal level of another one of the plurality of signals is switched at a timing different from a timing at which the gain value of the another one of the plurality of signals is switched.