Shared Detector Transmitter Circuit for Multi-Band RF Accuracy
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Solution Overview
Problem
In transmitters with shared detector circuits for multiple frequency bands, interference and reduced detection sensitivity occur, leading to increased signal power requirements and current consumption, which increases costs and power usage.
Innovation Solution
A transmitter design that includes a filter circuit or phase shifter between the output signal line of a lower frequency transmitting circuit and the detector circuit, allowing for high detection accuracy without increasing signal power, by selectively passing signals and controlling impedance and phase shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a detector circuit is shared among multiple transmitting circuits of different frequency bands, then cost and mounting area are reduced, but detection sensitivity decreases and interference occurs
Solution Approach 1:
The patent divides the frequency spectrum into different bands and uses band-specific filtering within the shared detector circuit. Each transmitting circuit's signal is separated by frequency-selective filters (such as SAW filters or LC filters) that allow only the relevant frequency band to reach the detector, preventing interference from other bands while maintaining a single shared detector circuit.
Solution Approach 2:
The patent introduces intermediary filtering components (frequency-selective filters, SAW filters, or phase shifters) between the multiple transmitting circuits and the shared detector circuit. These intermediaries selectively pass or block specific frequency bands, enabling the detector to accurately measure power from one transmitting circuit without being affected by others.
2Measurement precision
If signal power is increased to maintain detection accuracy in shared detector circuits, then detection accuracy is maintained, but current consumption increases
Solution Approach 1:
The patent extracts and removes unwanted frequency components from the signal path using frequency-selective filters before they reach the detector circuit. By taking out interfering signals from other frequency bands, the detector can maintain high detection accuracy with lower signal power levels, as it only needs to detect the relevant frequency band without competing with out-of-band interference.
Solution Approach 2:
The patent converts the potentially harmful interference from other frequency bands into a beneficial frequency-selective filtering mechanism. By using SAW filters or LC resonators tuned to specific frequencies, the circuit transforms what would be noise into a selective signal path, allowing accurate detection at lower power levels while the filtered-out frequencies are effectively eliminated rather than causing interference.
3Measurement precision
If a filter circuit is added between transmitting circuits and detector, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent changes the frequency parameter of the signal path by introducing frequency-selective filters with specific resonant frequencies matched to each transmitting circuit's operating frequency. These filters (SAW filters, LC filters, or phase shifters) are designed with parameters that naturally select the desired frequency band, providing accurate detection without requiring complex active filtering or multiple separate detector circuits.
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 design achieves high detection accuracy across multiple frequency bands with reduced power loss and current consumption, even when a detector circuit is shared among transmitting circuits, without increasing signal power to the detector circuit.
Implementation Method 1
a filter circuit which, arranged between the input terminal and the branched output terminal of the second coupler, selectively passes a signal of the second frequency band
Implementation Method 2
a phase shifter, providing a signal of the first frequency band with a larger phase shift than that for a signal of the second frequency band
Data Source
AI summary
To provide a transmitter wherein even in a case of sharing a detector circuit between or among a plurality of transmitting circuits, a high degree of detection accuracy can be achieved without increasing the signal power supplied to the detector circuit. In a transmitter including a detector circuit 14 shared by transmitting circuits 1 and 2 that deal with signals of different frequency bands, a capacitor C1, which constitutes an RF coupler disposed on an output signal line of the transmitting circuit 1, is directly connected to the input terminal of the detector circuit 14, while series coils L1 and L2 are inserted between a capacitor C2, which makes up an RF coupler disposed on an output signal line of the transmitting circuit 2 which deals with signals of a lower frequency band than the transmitting circuit 1, and the input terminal of the detector circuit 14.