V-Band Digital Bandpass Amplifier With Switchable Gain Networks
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Solution Overview
Problem
Existing wireless communications receivers face challenges in controlling gigahertz frequency signals due to intensive and susceptible design of feedback network filtering, especially at GHz and V-band frequencies, which complicates the recovery of signals at varying input levels.
Innovation Solution
A low-noise radio frequency digital gain control amplifier with a 12th-order bandpass filter and switchable gain amplifier networks, utilizing digitally controlled transistors and transmission gates to minimize component count and optimize noise and distortion, allowing for variable gain control from 3.1 dB to 40.5 dB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback network filtering is used to control signal strength, then signal recovery at varying input levels is improved, but design complexity and susceptibility to component variations increase
Solution Approach 1:
The patent replaces the analog feedback network with a digital control system. Digital logic circuits generate control signals that directly adjust the gain of variable gain amplifiers, eliminating the need for complex analog filtering networks and their associated component tolerances.
Solution Approach 2:
The patent uses digital control to dynamically adjust amplifier gain parameters. By changing digital control words, the gain can be precisely adjusted in discrete steps, providing flexible signal level control without redesigning the feedback network.
2Measurement precision
If feedback network filtering is used to control signal strength, then signal recovery at varying input levels is improved, but susceptibility to component variations increases
Solution Approach 1:
The patent replaces the analog feedback network with a digital control system. Digital logic circuits generate control signals that directly adjust the gain of variable gain amplifiers, eliminating the need for complex analog filtering networks and their associated component tolerances.
3Measurement precision
If digitally controlled amplifiers with switchable gain networks are used, then gain control precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the gain control function into multiple discrete variable gain amplifier stages, each controlled by digital logic. This segmentation allows precise gain control through digital word combinations while maintaining modular architecture that simplifies overall design.
Data Source
AI summary
A digitally controlled amplifier (DCA) has a drive (e.g., bipolar junction) transistor with a base to accept an input signal and a collector to supply an output signal. The DCA also includes n switchable gain amplifier networks (SGANs). Each SGAN has a signal input connected to the collector of the drive transistor, an input to accept a logic signal, and a signal output to supply a switchable gain AC output signal to a load in response to the logic signal. The SGAN signal outputs are connected together, typically in parallel, to supply a digitally controlled AC output gain. An auxiliary SGAN may be connected to supply a constant gain AC output signal. Each of the SGANs may have an identical switchable AC gain and accept an independent logic signal to supply (n+1) levels of digitally controlled AC output gain.