Dynamic Threshold Limiting for Frequency-Hopping Signal Glitches
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing amplitude limiter circuits distort audio signals by cutting off high amplitude components, leading to reduced signal quality, especially during frequency hopping processes where periodic glitches occur.
Innovation Solution
A device that dynamically sets threshold values based on the signal profile's mean values, with an offset, to limit interference amplitudes adaptively and only during expected glitches, ensuring the useful signal is not distorted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a fixed threshold amplitude limiter circuit is used, then interference amplitudes are limited, but high amplitude useful signal components are cut off causing distortion
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed threshold limiter to a dynamic threshold system where the threshold value adapts to the signal characteristics. The threshold is calculated as a function of the signal envelope, allowing it to vary over time to match the useful signal's amplitude profile, thus preventing distortion of high amplitude components while still limiting interference.
Solution Approach 2:
The patent changes the parameter of the threshold value from a constant to a variable that depends on signal characteristics. By making the threshold a dynamic parameter that adjusts according to the signal envelope and time constants, the system can differentiate between useful signal variations and interference, maintaining signal quality while limiting harmful amplitudes.
2Object-affected harmful factors
If amplitude limiting is applied during frequency hopping, then interference pulses are suppressed, but periodic glitches occur in the audio signal
Solution Approach 1:
The patent addresses periodic glitches by introducing synchronization with the frequency hopping pattern. The amplitude limiting operation is coordinated with the known periodicity of frequency hops, allowing the system to anticipate and properly handle amplitude transitions that occur during frequency switching, thereby eliminating periodic glitches in the audio output.
Solution Approach 2:
The system uses feedback by monitoring the signal envelope and using it to dynamically adjust the threshold. This closed-loop approach allows the limiter to respond to actual signal conditions rather than operating with a fixed threshold, preventing the periodic glitches that occur when fixed threshold limiting interferes with the natural signal dynamics during frequency hopping.
3Manufacturing precision
If a dynamic threshold is calculated from signal mean values, then signal quality is maintained, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical or analog threshold adjustment mechanisms with electronic signal processing. By using electronic circuits to calculate mean values and dynamically generate thresholds based on mathematical operations on the signal envelope, the system achieves dynamic thresholding with simpler, more reliable electronic components rather than complex mechanical adjustment systems.
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
The device has an input (6), and an output (23) to output a threshold value determined in the device or signal characteristics lying in the input. The value is formed from the characteristic and from which average values are computed with in a defined period. The average value is provided for forming the threshold value with an offset. The offset is a temporal constant value, and the device is activated by a control signal, which is coupled to an event such as to a frequency jumping. An independent claim is also included for a method for limiting parasitic amplitudes in signal characteristics to dynamically determined threshold values that are adjustable relative to an middle signal characteristic.