RF Transmitter Amplifier Ramping Without Negative Bias
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Solution Overview
Problem
Existing RF transmitters face challenges in quickly ramping up and down from minimal to information-bearing output power without violating peak power limits in spectral bands, often requiring negative DC voltage, which complicates disabling the transmission and increases bandwidth requirements.
Innovation Solution
The solution involves using a trapezoid signal to gradually increase the enable signal for amplification, allowing for precise control of power output through a mechanism that converts square signals into trapezoid signals, enabling a non-binary impedance adjustment in the enable transistor, thereby avoiding the need for negative voltage and reducing bandwidth usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the AC amplitude is higher than the DC amplitude in the amplifier input signal, then the transmission can be enabled, but it becomes difficult to disable the transmission without using negative DC voltage
Solution Approach 1:
The patent changes the parameter of DC voltage from negative to positive by introducing a ramping signal that gradually increases the DC voltage level. This allows the amplifier to be disabled by simply reducing the ramping signal amplitude, eliminating the need for negative voltage generation hardware.
Solution Approach 2:
The patent introduces a ramping signal as an intermediary between the control signal and the amplifier input. This ramping signal gradually increases the DC voltage component, serving as a mediator that enables smooth transition between transmission states without requiring direct negative voltage application.
2Productivity
If the transmitter ramps quickly from minimal to information-bearing output power, then the transmission efficiency is improved, but it may violate peak power limits in spectral bands
Solution Approach 1:
The patent applies dynamic control by using a ramping signal that continuously adjusts the DC voltage level during transmission. This dynamic adjustment allows the transmitter to quickly ramp up power while maintaining control over the spectral characteristics, preventing peak power violations through continuous optimization of the voltage waveform.
3Reliability
If negative DC voltage is used to disable the amplification, then the transmission can be reliably disabled, but additional hardware modules such as negative voltage generator are required
Solution Approach 1:
The patent extracts the negative voltage generation requirement from the system by using a positive DC voltage combined with a ramping signal. The disabling function is achieved by controlling the ramping signal amplitude rather than by generating negative voltage, thereby removing the need for negative voltage generator hardware modules.
Data Source
AI summary
The subject matter discloses a method of amplifying a signal, the method comprising receiving a command to start transmission, gradually increasing a value of an enable signal used to amplify the transmission and intermittently transmitting the value of the enable signal to an enable transistor used to allow amplifying a transmitted signal.