Digital TV Receiver AGC for Noise-Aware Signal Digitization
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Solution Overview
Problem
Existing digital television receivers amplify noise signals along with data signals, leading to saturation of amplifiers and converters in harsh environments, due to inadequate noise separation and gain control.
Innovation Solution
A receiver system that includes a first amplifier, a filter, a second amplifier, and an analog-to-digital converter, with automatic gain control (AGC) means that use estimated optimal power and generalized moments to determine control signals, accounting for noise signals and preventing amplifier saturation by adjusting gains based on the power of the analog signal before filtering and the converted digital signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If amplifiers are used to amplify the analogical signal before filtering and conversion, then the signal power is increased for optimal converter use, but noise signals are also amplified leading to saturation of amplifiers or converter
Solution Approach 1:
The patent divides the amplification function into two separate amplifiers: a first amplifier before the filter and a second amplifier before the converter. This segmentation allows independent control of each amplifier's gain, enabling the first amplifier to amplify the signal while the filter removes noise, and the second amplifier to amplify the filtered signal without saturation risk from noise
Solution Approach 2:
The patent implements automatic gain control (AGC) means that measure parameters of the converted digital data signal and adjust the gains of both amplifiers accordingly. The AGC creates a feedback loop where the system continuously monitors signal quality and adjusts amplification to prevent saturation while maintaining optimal signal power throughout the conversion process
2Productivity
If automatic gain control adjusts amplifier gains based on digital signal power, then optimal converter use is achieved, but noise signals are not distinguished from data signals leading to saturation in harsh environments
Solution Approach 1:
The patent applies filtering before the second amplification stage to remove noise signals from the analogical signal. This preliminary action of noise removal before amplification ensures that when the AGC adjusts gains based on signal power, only the data signal is being amplified, preventing noise-induced saturation in harsh environments
Solution Approach 2:
The patent applies different processing characteristics to different parts of the signal chain: the first amplifier operates on the raw signal including noise, the filter selectively removes noise frequencies, and the second amplifier operates on the cleaned signal. This local differentiation of processing quality allows optimal converter efficiency while protecting against noise interference
Data Source
AI summary
This device (10) includes elements (12) for receiving an analogical signal including a data signal in a frequency channel, elements (18) for amplifying the received signal, elements (20) for filtering the amplified signal so as to cut out frequencies outside the frequency channel of the data signal, members (24) for converting the filtered analogical signal into a digital signal, elements (32) for measuring the power (Pwhole) of the whole received signal after amplification and before filtering, and members (26) for determining an amplification control signal for the received signal amplification as a function of the received signal measured power (Pwhole).