Switched Capacitor Filter for Manchester Demodulation Delay
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Solution Overview
Problem
Existing Manchester code demodulators require active components for signal delay, leading to signal distortion and increased supply current, which are not efficiently addressed by traditional matched filter circuits.
Innovation Solution
A switched capacitor filter circuit is employed, comprising sampling and filter switches with capacitors, controlled by a controller to provide switching signals, allowing for in-phase and quadrature output signals and enabling a programmable delay without active components, thus mimicking a matched filter's impulse response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If active components are used to delay the input signal in a matched filter circuit, then the signal delay function is achieved, but signal distortion occurs and supply current increases
Solution Approach 1:
The patent extracts the delay function from active components and implements it using passive switched capacitor circuits. The delay is achieved by sampling the input signal at different times using switches controlled by a clock signal, eliminating the need for active delay components that cause distortion and high current consumption.
Solution Approach 2:
The patent replaces the traditional active electronic delay mechanism with a switched capacitor system that uses clocked switches and capacitors to achieve the same delay effect. This substitution of the delay mechanism eliminates the harmful effects of active components while maintaining the required time delay function.
2Loss of time
If active components are used to delay the input signal in a matched filter circuit, then the signal delay function is achieved, but supply current increases
Solution Approach 1:
The patent extracts the delay function from active components and implements it using passive switched capacitor circuits. The delay is achieved by sampling the input signal at different times using switches controlled by a clock signal, eliminating the need for active delay components that cause distortion and high current consumption.
Solution Approach 2:
The patent employs periodic switching of capacitors at a clock frequency to achieve the delay function. The switches are controlled by periodic clock signals that sample and hold signal values at different phases, creating the required time delay without continuous active component operation, thereby reducing power consumption.
3Ease of operation
If traditional matched filter circuits are used for Manchester code demodulation, then the demodulation function is achieved, but active components cause signal distortion and higher current consumption
Solution Approach 1:
The patent extracts the delay function from active components and implements it using passive switched capacitor circuits. The delay is achieved by sampling the input signal at different times using switches controlled by a clock signal, eliminating the need for active delay components that cause distortion and high current consumption.
Solution Approach 2:
The patent replaces the traditional active electronic delay mechanism with a switched capacitor system that uses clocked switches and capacitors to achieve the same delay effect. This substitution of the delay mechanism eliminates the harmful effects of active components while maintaining the required time delay function.
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 reduces the need for active components, minimizing signal distortion and supply current while effectively demodulating Manchester codes, achieving a matched filter's performance without the associated drawbacks.
Implementation Method 1
a first sampling switch connected between the input connection and a first node; a sampling capacitor connected between the first node and a common connection
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
This disclosure relates to a switched capacitor filter circuit for a Manchester code demodulator. An example embodiment includes a filter circuit (800) comprising: an input connection (601); a plurality of output connections (602a-f); and a plurality of switched capacitor circuits (603a-f), each switched capacitor circuit (603a-f) comprising: a first sampling switch (604a-f) connected between the input connection (601) and a first node (605a-f); a sampling capacitor (606a-f) connected between the first node (605a-f) and a common connection (407); and a first filter switch (608a-f) connected between the first node (605a-f) and a second node (6111), the circuit (800) further comprising a first filter capacitor (6121) connected between the second node (6111) of each of the switched capacitor circuits (603a-f) and the common connection (407).