Signal Attenuation Circuit Using MOS Switches for Smooth Gain Control
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Solution Overview
Problem
Existing signal processing and communication systems face challenges in varying attenuation amounts without increasing circuit scale and power consumption, with capacitor attenuators leading to higher circuit scale and resistor attenuators resulting in stepwise gain control and potential picture quality degradation.
Innovation Solution
A signal processing apparatus and method that includes a short-circuiting controlling section and a connection controlling section with MOS transistors, where the switches change states based on signal levels to control resistor connections, allowing continuous variation of attenuation while suppressing circuit scale and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a capacitor attenuator is used, then the distortion characteristic is improved, but the circuit scale and power consumption increase
Solution Approach 1:
The patent extracts the essential attenuation function from complex capacitor attenuator circuits and implements it using a simplified resistor-based voltage divider configuration. By removing unnecessary circuit components and focusing on the core voltage division principle, the invention achieves distortion correction without the circuit complexity of capacitor attenuators.
Solution Approach 2:
The patent replaces expensive and complex capacitor attenuator components with simpler, more economical resistor-based components. This substitution uses readily available resistors and switches that are cheaper and easier to implement while achieving the same functional goal of signal level attenuation and distortion reduction.
2Device complexity
If a resistor attenuator is used, then the circuit scale is reduced, but the gain control becomes stepwise causing picture quality deterioration
Solution Approach 1:
The patent transforms the static, stepwise resistor attenuator into a dynamic system where MOS switches are controlled by varying control voltages. This allows the attenuation amount to change continuously rather than in discrete steps, eliminating the stepwise gain control effect that causes picture quality deterioration while maintaining the simple resistor-based circuit structure.
Solution Approach 2:
The patent changes the control parameter from digital switching signals to analog control voltages that vary continuously. By applying control voltages with different potentials to the gates of MOS switches, the invention achieves continuous variation of the attenuation amount, transforming the stepwise characteristic into a smooth, continuous gain control that prevents picture quality issues.
3Measurement precision
If digital control is used for attenuation, then the control precision is improved, but instantaneous luminance variation occurs
Solution Approach 1:
The patent applies preliminary action by using control voltages that are applied in advance to the MOS switch gates before the actual attenuation is needed. This allows the switches to be gradually adjusted to their target states, preventing sudden changes in signal level that would cause instantaneous luminance variation on display images.
Solution Approach 2:
The patent introduces control voltages as an intermediary between the digital control signal and the physical attenuation process. These control voltages act as a mediator that smoothly transitions the MOS switch states, eliminating the direct, abrupt connection between digital switching and analog signal attenuation that causes luminance flicker.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables continuous variation of attenuation amounts, improving signal processing quality by reducing sudden fluctuations and eliminating the need for digital processing, thereby minimizing circuit scale and power consumption.
Implementation Method 1
the switches are individually configured from an MOS (metal oxide semiconductor) transistor whose gate potential varies in response to the signal level of the signal
Data Source
AI summary
The present disclosure provides a signal processing apparatus including: a short-circuiting controlling section configured to control whether or not the input side of a resistor connected between an input terminal and an output terminal and the output terminal are to be short-circuited in response to a signal level of a signal inputted from the input terminal; and a connection controlling section configured to control whether or not a resistor member is to be connected between the output terminal and a reference potential in response to the signal level of the signal, wherein at least one of the short-circuiting controlling section and the connection controlling section includes a plurality of switches disposed in parallel to each other for changing over a state thereof between open and closed states at signal levels different from each other.