Homodyne Detector Charge Impedance Evaluation Circuit
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Solution Overview
Problem
Radio frequency transceiver systems face reliability issues due to parasitic signals from other frequency bands interfering with measurements of charge impedance at the output of directional couplers, leading to erroneous antenna matching and communication alterations, and current solutions involving demodulation are costly.
Innovation Solution
A circuit using a homodyne detector with a variable-gain amplifier and low-pass filters to process signals from a directional coupler, allowing for the separation and filtering of desired and parasitic frequency bands, thereby improving measurement reliability without the need for demodulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If demodulators are used to remove parasitic frequency bands from the coupler output, then measurement reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts only the necessary function of frequency selection from the complex demodulator and implements it through a simple band-pass filter. This filter removes parasitic frequency bands before the signal reaches the detection circuit, achieving reliable measurements without requiring full demodulation functionality. The solution takes out the essential filtering capability while discarding the complex demodulation hardware.
Solution Approach 2:
The patent replaces expensive demodulator circuits with a simple, low-cost band-pass filter. The filter is a minimalistic component that performs the essential function of removing parasitic frequencies without the complexity and cost of demodulation circuits. This substitution uses a cheap, simple component to achieve the required measurement reliability.
2Measurement precision
If demodulation is performed to properly calculate reflection loss, then measurement accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts the essential frequency selection function from the demodulator and implements it through a simple band-pass filter. This filter removes parasitic frequency bands before detection, ensuring accurate reflection loss measurements without requiring expensive demodulation circuits. The solution maintains measurement precision while dramatically reducing manufacturing complexity and cost.
Solution Approach 2:
The patent substitutes expensive demodulation circuits with a simple, low-cost band-pass filter that performs the critical function of parasitic frequency removal. This minimalistic approach achieves accurate measurements without the high manufacturing costs associated with demodulator implementation.
3Measurement precision
If parasitic signals from other frequency bands are present at the coupler output, then the desired signal measurement is corrupted, but adding complex filtering increases device complexity
Solution Approach 1:
The patent extracts the essential frequency selection function and implements it through a simple band-pass filter placed at the coupler output. This filter removes parasitic frequency bands before they can corrupt the measurement, achieving signal accuracy without complex filtering circuits. The solution takes out only the necessary filtering capability while avoiding unnecessary complexity.
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
This solution enhances the reliability of charge impedance measurements by effectively filtering out parasitic signals, reducing errors in antenna matching and communication, while avoiding the high costs associated with demodulation techniques.
Implementation Method 1
a homodyne detector having a first input for a signal to be processed connected to said second input terminal and having a second local oscillator input connected to said first input terminal
Implementation Method 2
a first low-pass filter having an input connected to a first output of the homodyne detector and providing first data relative to the charge impedance
Data Source
AI summary
A method and circuit for evaluating a charge impedance at the output of a directional coupling having a first line adapted to convey a desired signal between a first terminal and a second terminal adapted to be connected to an antenna, and having a second line coupled to the first one including a third terminal on the side of the first terminal and a fourth terminal on the side of the second terminal, wherein the signal present on the fourth terminal is submitted to a homodyne detector having its local oscillator signal sampled from the third terminal.