T/R Switch High Insertion Loss Mode for Power Reduction
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Solution Overview
Problem
Current wireless communication devices face challenges in reducing transmit and receive power effectively, leading to issues such as TX frequency splatter, PLL/LO leakage, and limited accuracy in achieving low TX output power, which can result in non-compliance with emission standards and interoperability issues.
Innovation Solution
The implementation of a transmit/receive (T/R) switch with a plurality of ports that selectively connects the transmitter or receiver to the antenna, allowing for high insertion loss mode operation, calibration of TX power using a TX to RX loopback signal, and programmable timers to reduce frequency splatter and LO leakage, thereby achieving precise power control and compliance with emission standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If transmit power is reduced to improve security and reduce emissions, then power consumption and harmful emissions are reduced, but communication reliability and signal quality deteriorate
Solution Approach 1:
The T/R switch is activated before the power amplifier ramps up to preemptively isolate the antenna from the transmitter during critical periods. This preliminary action prevents frequency splatter and LO leakage before they occur, while maintaining communication reliability by ensuring the switch is already in place when the PA activates.
Solution Approach 2:
The T/R switch acts as an intermediary component between the antenna and the transmitter/receiver. It mediates the connection by providing isolation during specific operations, allowing the system to reduce harmful emissions while maintaining reliable communication through controlled connectivity.
2Object-generated harmful factors
If T/R switch isolation is used to reduce TX output power, then emission compliance is improved, but insertion loss increases
Solution Approach 1:
The T/R switch operates periodically, providing isolation only during specific intervals when the power amplifier is ramping up or down. During normal operation, the switch connects the antenna to the transmitter, eliminating continuous insertion loss while still achieving emission compliance during critical transition periods.
Solution Approach 2:
The system applies T/R switch isolation partially, only during the periods when emission control is needed (PA ramp up/down), rather than continuously. This partial application achieves sufficient emission compliance while minimizing the overall impact of insertion loss on communication performance.
3Object-generated harmful factors
If T/R switch is activated early to prevent frequency splatter, then emission compliance is improved, but device complexity and control requirements increase
Solution Approach 1:
The system uses feedback from the power amplifier's operational state to control the T/R switch. The switch controller monitors when the PA is ramping up or down and automatically activates the switch during these periods, providing emission compliance through automated feedback-based control rather than complex manual timing.
Solution Approach 2:
The T/R switch control is merged with the existing power amplifier control logic. By integrating the switch activation with the PA's ramp up/down sequences, the system reduces overall control complexity while still achieving the goal of preventing frequency splatter during critical periods.
Data Source
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AI summary
A wireless communication device is described. The wireless communication device includes a transmit/receive (T/R) switch that is configured with an antenna port coupled to an antenna, a transmitter port coupled to a transmitter and a receiver port coupled to a receiver. The T/R switch selectively connects the transmitter port to the antenna port or the receiver port to the antenna port. The wireless communication device also includes a T/R switch controller that sets the T/R switch to disconnect the transmitter from the antenna when the transmitter is actively transmitting in a high insertion loss mode to reduce power from the transmitter to the antenna.