Analog Bias Circuit for Smooth Wireless Transceiver Gain Modulation
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Solution Overview
Problem
The existing bias circuits in wireless transceivers cause transient response issues during gain modulation of amplifiers, leading to reduced operation performance due to digital control signals and delayed detection of signal strength, resulting in incorrect gain modulation.
Innovation Solution
A bias circuit that modulates amplifier gain using an analog form of current variation, with a first stage bias unit generating an outputting current based on constant current and control voltage, and a converter to regulate voltage for smooth gain modulation, preventing transient response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If digital control signals are used to modulate the gain of the amplifier, then the gain can be controlled according to signal strength, but transient response occurs during gain modulation
Solution Approach 1:
The patent introduces a bias circuit as an intermediary component between the digital control signal and the amplifier. This bias circuit converts digital control signals into analog bias currents that smoothly adjust the amplifier's operating point, thereby eliminating transient responses while maintaining gain control capability
Solution Approach 2:
The patent replaces the direct digital control mechanism with an analog biasing mechanism. Instead of using digital switches or modulators that cause transient responses, the system uses analog bias currents to continuously adjust the amplifier gain, substituting a smooth analog control mechanism for a discrete digital one
2Measurement precision
If the rear-end circuit detects signal strength after transient response, then detection can be performed, but detection error occurs due to delayed processing
Solution Approach 1:
The patent implements preliminary action by using the bias circuit to preemptively smooth the gain modulation before the amplifier processes the signal. By eliminating transient responses in advance, the rear-end circuit can immediately detect accurate signal strength without waiting for transient conditions to subside, thus reducing detection delay while maintaining precision
3Adaptability or versatility
If gain modulation is performed with digital control, then multi-level digital scaling can be implemented, but operation performance is reduced due to transient response
Solution Approach 1:
The bias circuit serves as a mediator that preserves the adaptability of multi-level digital scaling while eliminating the harmful transient responses. It translates discrete digital control levels into smooth analog bias adjustments, maintaining the versatility of gain control across multiple levels while improving overall operation performance
Data Source
AI summary
A bias circuit for the wireless transceiver is disclosed, which can be used for modulating the gain of the amplifier. The bias circuit comprises a first stage bias unit for receiving a constant current, a control voltage, and a first reference voltage and outputting a first outputting current, wherein the control voltage is used for controlling the value of the first outputting current, and further, the first outputting current can be increased or decreased by representing as an analog form, thus, the gain of the amplifier can be modulated according to the first outputting current, and the modulation of the gain can be represented as an analog form, such that the transient response occurred while the gain is modulated can be reduced.