Interrogator Phase Control for Long-Range Transponder Demodulation
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Solution Overview
Problem
Conventional communication systems face challenges in detecting modulation signals from transponders, especially at long distances or when multiple transponders are involved, due to interference and low signal strength.
Innovation Solution
An interrogator system is designed with a transmitting portion, a receiving portion, a first frequency converting portion, a second frequency converting portion, and a phase controlling portion to generate and control local signals, enabling the extraction of modulation-related signals with high signal-to-noise ratios by aligning the phase of the second local signal with the desired wave and orthogonal to interference waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional automatic gain control circuits are used to detect modulation signals, then gain adjustment can be performed, but the signal-to-noise ratio deteriorates when communication distance is long or multiple transponders are present
Solution Approach 1:
The frequency conversion process is divided into two distinct stages: first frequency conversion to intermediate frequency, then second frequency conversion to base frequency. This segmentation allows separate optimization of each conversion stage, with the first stage handling frequency translation and the second stage focusing on signal demodulation with phase control, thereby improving signal-to-noise ratio
Solution Approach 2:
The invention changes the frequency parameter through two-stage conversion and controls the phase parameter of the second local signal. By adjusting these parameters, the system can extract modulation signals with high signal-to-noise ratio even when communication distance is long or multiple transponders are present
2Length of moving object
If communication distance is increased, then transponder detection range is improved, but signal strength decreases making modulation detection difficult
Solution Approach 1:
The frequency conversion is segmented into two stages with different local oscillators. The first stage converts to intermediate frequency and the second stage converts to base frequency with phase control capability, enabling effective extraction of weak modulation signals from long-distance transponders
Solution Approach 2:
The phase controlling portion uses feedback mechanisms to adjust the phase of the second local signal based on the received signal characteristics, maximizing the signal-to-noise ratio of the extracted modulation signal even at extended communication distances
3Adaptability or versatility
If multiple transponders are present, then system versatility is improved, but interference between transponders increases making signal detection difficult
Solution Approach 1:
The two-stage frequency conversion process segments the signal processing tasks, allowing the second stage to focus on demodulation with phase control. This segmentation enables the system to handle multiple transponder signals by controlling the phase of the second local signal to align with desired signals and orthogonal to interference waves
Solution Approach 2:
By controlling the phase parameter of the second local signal, the system can selectively enhance desired modulation signals while suppressing interference from other transponders, thereby maintaining multi-transponder versatility without suffering from interference degradation
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 configuration allows for reliable detection of modulation signals even at long distances and in the presence of interference, significantly increasing the communicable range and maintaining signal quality during transponder movement.
Implementation Method 1
a first frequency converting portion operable to generate an intermediate frequency signal, by multiplying the received signal with a first local signal that is generated by a first local oscillator
Implementation Method 2
a second frequency converting portion operable to generate a demodulated signal, by multiplying the intermediate frequency signal or a converted signal converted from the intermediate frequency signal, with a second local signal that is generated by a second local oscillator
Data Source
AI summary
An interrogator that is to be incorporated in a communication system in which each of at least one transponder is operable, upon reception of a main carrier wave transmitted from the interrogator, to respond to the interrogator with a reflected wave that is generated by modulating the main carrier wave. The interrogator includes: (a) a transmitting portion operable to transmit the main carrier wave; (b) a receiving portion operable to receive the reflected wave as a received signal; (c) at least one first frequency-converter each operable to generate an intermediate frequency signal, by multiplying the received signal with a first local signal that is generated by a first local oscillator; (d) at least one second frequency-converter each operable to generate a demodulated signal, by multiplying the intermediate frequency signal or a converted signal converted from the intermediate frequency signal, with a second local signal that is generated by a second local oscillator; and (d) a phase controller operable to control phase of the second local signal.