Variable Attenuation Transmission Circuit for SNR and Dynamic Range
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Solution Overview
Problem
Conventional transmission systems face issues with signal degradation due to large transmission losses and noise, leading to a narrow dynamic range that can prevent signal reception.
Innovation Solution
A transmission system with a transmitter that includes an amplification circuit and a receiver equipped with an amplitude comparison circuit, a variable attenuation circuit, and an amplitude limiting circuit, which dynamically adjusts signal attenuation based on the received amplitude relative to a reference voltage, ensuring the signal amplitude remains above the minimum required for communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed attenuation circuit is used to improve signal-to-noise ratio, then the SN ratio is improved by G times, but the dynamic range becomes narrower and signals with large transmission loss cannot be received
Solution Approach 1:
The patent applies dynamics by replacing the fixed attenuation circuit with a variable attenuation circuit that dynamically adjusts its attenuation factor based on the received signal strength. The control circuit monitors the input signal amplitude and selectively activates the variable attenuation circuit to provide appropriate attenuation levels, thereby maintaining both high signal-to-noise ratio for strong signals and adequate dynamic range for weak signals.
Solution Approach 2:
The patent changes the attenuation parameter from a fixed value to a variable value that adapts to different signal conditions. The variable attenuation circuit modifies its attenuation factor according to the input signal characteristics, allowing the system to optimize signal-to-noise ratio when needed while preserving dynamic range when signals are weak.
2Reliability
If signal amplitude is stepped up by transmission amplifier, then the SN ratio is improved, but transmission loss and noise on the transmission line still degrade characteristics
Solution Approach 1:
The patent applies preliminary action by performing amplification at the transmitter end before signal transmission. The transmission amplifier boosts the signal amplitude in advance, ensuring that even after transmission loss and noise degradation, the received signal maintains adequate strength and signal-to-noise ratio.
Data Source
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AI summary
Provided is a transmission system capable of improving the SN ratio for noise superimposed on a transmission line and extending the dynamic range. The transmission system transmits a signal between a transmitter (1) and a receiver (3), which are connected to each other via a transmission line (2). The transmitter (1) includes a transmission amplifier (11) for stepping up an amplitude of an input signal. The receiver (3) includes: an amplitude comparison circuit (31) for attenuating the amplitude of the signal, which is output from the transmission amplifier (11) and input via the transmission line (2), and comparing the attenuated amplitude and a reference voltage; a variable attenuation circuit (32) for outputting, when the attenuated amplitude is larger than the reference voltage, the signal input to the receiver (3) after attenuating the amplitude of the signal, and for outputting, when the attenuated amplitude is smaller than the reference voltage, the signal input to the receiver (3) without attenuating the amplitude of the signal; and an amplitude limiting circuit (33) for clipping the amplitude of the signal output from the variable attenuation circuit (32) at a threshold voltage.