Aircraft Communication Equalizer for Distant Echo Cancellation
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Solution Overview
Problem
Conventional equalizers are inadequate for processing significant delays caused by ground and sea echoes in aircraft communications, leading to detrimental inter-symbol interference due to their limited processing depth and complexity in handling distant reflections.
Innovation Solution
An on-board device estimates the distance and delay of the main echo, subtracts a delayed version of the signal, and applies a coefficient to minimize interference, using altitude measurements and differential Doppler shift calculations to reduce the contribution of the main echo to the total interference level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional equalizers with limited processing depth are used, then device complexity is reduced, but they cannot process significant delays caused by distant echoes, leading to inter-symbol interference
Solution Approach 1:
The equalizer is divided into multiple processing stages: a first equalizer processes signals within its processing depth, while a second equalizer processes signals beyond that depth. This segmentation allows the system to handle both near and far echoes effectively, resolving the contradiction between limited processing depth and the need to handle significant delays from distant reflections.
Solution Approach 2:
The patent extends the equalization process into a new dimension by adding a second equalizer that operates beyond the processing depth of the first equalizer. This dimensional extension in the delay domain enables the system to process both short and long delay paths, thereby improving communication reliability without requiring a single overly complex equalizer.
2Reliability
If conventional equalizers process only a small range of delays, then processing speed is maintained, but distant path interference cannot be eliminated
Solution Approach 1:
The time delay processing range is segmented into two portions: the first equalizer handles delays within its processing depth T, while the second equalizer handles delays beyond T. This temporal segmentation enables comprehensive interference cancellation across the full delay spectrum without sacrificing processing speed, as each equalizer operates independently within its designated time window.
3Reliability
If the processing depth T is increased to cover distant echoes, then interference cancellation improves, but device complexity and computational load increase significantly
Solution Approach 1:
Instead of using a single equalizer with increased processing depth, the system segments the processing function across two equalizers with moderate individual depths. The first equalizer processes delays up to T, and the second equalizer processes delays beyond T. This segmentation distributes the computational load, avoiding the exponential complexity increase that would result from a single deep equalizer while achieving the same overall echo processing capability.
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
This approach enhances the robustness of communications and bit error rate, allowing for effective interference cancellation and equalization of distant paths, improving communication reliability in the presence of natural interference.
Implementation Method 1
c represents the speed of light expressed in m/s
Implementation Method 2
The device comprises, for example, means for estimating the differential Doppler shift Δf diff using the following expression
Implementation Method 3
The device comprises means for subtracting from the received signal s(t) a version delayed by τ of said signal in order to reduce the contribution of the main echo to the total level of interference in reception
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a heat exchanger comprising fluid exchange and flow elements (2, 2', 3), at least one fluid-collecting box (11, 11') into which the exchange elements (2, 2', 3) lead, at least one collector plate (10) for supporting the exchange elements (2, 2', 3), and a casing (4) for housing the exchange elements (2, 2', 3). The exchanger is characterized in that said exchanger comprises a flange (5) for attaching the collecting box (11, 11') to the casing (4). By means of the invention, the transmission of forces from the flange (5) to the collector plate (10) is prevented, thus making it possible to form a collector plate (10) having a lower thickness.