CMOS Super-Heterodyne TV Receiver with Multi-Path Linearity
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Solution Overview
Problem
Traditional super-heterodyne television receivers using bipolar technology are costly and have not been successfully integrated using CMOS technology due to linearity issues with CMOS amplifiers, which limits their implementation in low-cost, high-performance television receivers.
Innovation Solution
Implementing an integrated super-heterodyne television receiver using a single CMOS chip with multiple signal paths, each equipped with CMOS low noise amplifiers, down-conversion mixers, and variable gain amplifiers to achieve adequate linearity across different frequency bands, thereby reducing costs without compromising performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If bipolar technology is used for super-heterodyne television receivers, then linearity performance is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the fundamental parameter of transistor technology from bipolar to CMOS, and simultaneously changes the amplifier architecture from single-stage to multi-stage with noise injection, achieving adequate linearity in CMOS technology for television receiver applications
Solution Approach 2:
The patent replaces expensive bipolar transistors with cheaper CMOS transistors, accepting that CMOS has inherently lower linearity but compensating through architectural design, thereby reducing manufacturing cost while maintaining acceptable performance
2Use of energy by moving object
If CMOS technology is used for integrated circuits, then power consumption is reduced, but linearity performance deteriorates
Solution Approach 1:
The patent segments the amplifier function into multiple stages (first amplifier, second amplifier) with different functions - the first provides gain while the second provides linearity correction through noise injection, allowing CMOS to achieve adequate linearity while maintaining low power consumption
Solution Approach 2:
The patent introduces an intermediary mechanism (noise injection from a noise source through a switch into the second amplifier) that actively corrects the linearity distortion inherent in CMOS amplifiers, enabling CMOS to achieve bipolar-like linearity performance while maintaining its power efficiency advantage
3Device complexity
If multiple signal paths are integrated on a single chip, then device integration is improved, but manufacturing complexity increases
Solution Approach 1:
The patent implements multiple signal paths (first signal path, second signal path) on a single CMOS chip, where each path contains complete functional blocks (amplifiers, filters, mixers) that can be independently activated, achieving multi-functionality and high integration while using standard CMOS fabrication processes
Solution Approach 2:
The patent merges multiple functional blocks (low noise amplifiers, variable gain amplifiers, filters, mixers, local oscillators) onto a single CMOS chip, integrating what were traditionally separate discrete components or bipolar circuits into one unified CMOS device, thereby reducing overall system complexity and cost
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
The solution enables the integration of low-cost, high-performance television receivers by addressing linearity issues in CMOS technology, allowing for the implementation of multiple signal paths on a single CMOS chip, which is more cost-efficient than traditional bipolar or BiCMOS implementations.
Implementation Method 1
Two frequencies can be mixed to produce the sum and the difference in a heterodyne process. A super-heterodyne receiver mixes a high frequency input signal with a local frequency generated in a receiver to produce a signal at a frequency that is the difference between the frequency of the input signal and the local frequency generated in the receiver.
Data Source
AI summary
Integrated super-heterodyne television receivers with multiple signal paths implemented using CMOS technology. An integrated circuit, includes: a plurality of CMOS (Complementary Metal-Oxide Semiconductor) low noise amplifiers; an adjustable frequency source; and one or more down-conversion mixers coupled with the adjustable frequency source and the plurality of CMOS low noise amplifiers to form a plurality of super-heterodyne receiving paths between an input to the plurality of CMOS low noise amplifiers and an output from one or more down-conversion mixers; where the integrated circuit is implemented on a single chip of semiconductive substrate.