Transceiver Arrangement With Adaptive Impedance Matching
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Solution Overview
Problem
Existing transceivers face challenges in frequency division duplex communication due to internal interference between transmitter and receiver signals, with current solutions like duplexers being costly, space-consuming, and difficult to implement on-chip, and alternative methods like dummy loads resulting in signal energy loss and transformer complexity.
Innovation Solution
A transceiver arrangement with a filtering structure and common-mode signal reduction circuit that uses adaptive impedance matching and filters of different types to minimize transmitter signal interference at the receiver input, eliminating the need for transformers and reducing signal loss in dummy loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a duplexer is used to prevent transmitter signal leakage to the receiver, then isolation between transmitter and receiver is improved, but device complexity, cost, and space consumption increase
Solution Approach 1:
The patent divides the single duplexer function into multiple filter components (first filter between transmitter and antenna, second filter between receiver and antenna, third filter between receiver and dummy load). Each filter handles a specific frequency range or signal path, collectively achieving the isolation function while allowing simpler individual implementations that can be integrated on-chip.
Solution Approach 2:
Different filter characteristics are applied to different signal paths based on local requirements. The first and second filters are designed with specific passband/stopband characteristics suited to their respective paths (transmitter to antenna, receiver to antenna), while the third filter is optimized for the receiver-to-dummy-load path. This localized optimization achieves overall system isolation with simpler individual components.
2Reliability
If a dummy load is used to balance impedance and reduce transmitter contribution at receiver input, then signal interference is reduced, but signal energy is lost in the dummy load
Solution Approach 1:
The patent discards the received signal that would otherwise be lost in the dummy load by providing a separate signal path from the antenna through the second filter directly to the receiver. The dummy load is used only for impedance balancing and common-mode rejection, while the useful received signal is recovered and directed to the receiver through the dedicated second filter path, eliminating energy waste.
3Reliability
If a transformer is used in the dummy load configuration to achieve differential input, then transmitter signal suppression is improved, but device complexity and implementation difficulty increase
Solution Approach 1:
The patent extracts and removes the transformer component from the circuit configuration. Instead of using a transformer to achieve differential input and common-mode rejection, the patent employs a transformerless dummy load configuration combined with the third filter (bandpass or notch filter) that provides the necessary common-mode signal rejection and impedance balancing without requiring magnetic coupling components that are difficult to integrate on-chip.
Solution Approach 2:
The patent replaces the mechanical/magnetic transformer system with an electrical filter-based solution. The third filter, configured as a bandpass or notch filter, provides the common-mode rejection and impedance transformation functions previously achieved by the transformer, using purely electrical components that are more suitable for on-chip integration.
4Reliability
If filters are added to the transceiver arrangement to reduce transmitter signal interference, then signal isolation is improved, but device complexity increases
Solution Approach 1:
The patent designs the filters to serve multiple functions simultaneously. The first filter not only provides isolation between the transmitter and antenna but also shapes the transmitted signal spectrum. The second filter provides both received signal filtering and isolation from the dummy load. The third filter serves dual purposes of impedance balancing and common-mode rejection. This multi-functionality reduces the need for additional dedicated components, offsetting the complexity increase from adding filters.
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 effectively reduces transmitter signal interference at the receiver input while minimizing signal loss, achieving efficient signal transmission and reception with reduced energy waste and simplified on-chip implementation.
Implementation Method 1
The filters of the first type are arranged to pass signals at transmitter frequency and attenuate signals at receiver frequency
Implementation Method 2
The filters of the second type are arranged to attenuate signals at transmitter frequency and pass signals at receiver frequency
Implementation Method 3
The common-mode signal reduction circuit comprises an inverting amplifier, the input of the inverting amplifier is provided by a voltage division between a first and a second impedance
Implementation Method 4
the input of the inverting amplifier is provided by a voltage division between a first and a second impedance where the first and second impedance have equal impedances
Implementation Method 5
a balancing impedance circuit arranged to provide an adaptive impedance arranged to mimic the impedance at the transmission port
Data Source
Figure 1~2
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Figure 4
AI summary
A transceiver arrangement comprising a receiver and a transmitter arranged for frequency-division duplex communication with a communication network, a transmission port for connecting to an antenna, a balancing impedance circuit arranged to provide an adaptive impedance arranged to mimic the impedance at the transmission port, a filtering arrangement connecting the receiver, transmitter, transmission port and balancing impedance circuit, and a common-mode signal reduction circuit is disclosed. The filter arrangement comprises filters of a first type arranged to pass signals at transmitter frequency and attenuate signals at receiver frequency and are connected between the transmitter and the transmission port and between the receiver and the balancing impedance circuit, and filters of a second type arranged to attenuate signals at transmitter frequency and pass signals at receiver frequency and are connected between the transmitter and the balancing impedance circuit and between the receiver and the transmission port. The common-mode signal reduction circuit comprises an inverting amplifier, the input of the inverting amplifier is provided by a voltage division between a first and a second impedance where the first and second impedance have equal impedances, and the output of the amplifier is provided to junction of a third and a fourth impedance where the third and fourth impedances have equal impedances, and the first and second impedances, and the third and fourth impedances, respectively, are connected in series between a filter of the first type and a filter of the second type. A communication device and method are also disclosed.