Frequency-Domain Automatic Gain Control With Lower CPU Load
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Solution Overview
Problem
Existing automatic gain control systems impose a high processing load on CPUs, making it difficult to perform appropriate gain control using low-processing-capability CPUs.
Innovation Solution
The system converts input signals to the frequency domain, calculates gain based on these signals, and multiplies the received signal by the gain, reducing processing load on the CPU while allowing for appropriate gain control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the average value of the input signal is calculated to perform gain control, then appropriate gain control can be achieved, but the processing load on the CPU increases
Solution Approach 1:
The patent extracts only the necessary components for gain control calculation. Instead of calculating the full average value of the input signal which requires extensive processing, the invention uses a simplified approach by calculating gain based on the ratio of output signal energy to input signal energy, extracting only the essential information needed for gain determination while discarding unnecessary computational steps
Solution Approach 2:
The patent changes the parameter used for gain calculation from time-domain average value to frequency-domain energy ratio. By transforming the signal to frequency domain and using energy spectral density, the calculation becomes more efficient. The gain is determined by comparing the energy of output signal to input signal in frequency domain, which reduces computational complexity while maintaining accuracy
2Reliability
If a CPU with high processing capability is used to calculate the average value, then appropriate gain control can be performed, but the device cost and complexity increase
Solution Approach 1:
The patent employs a computationally inexpensive method that can be executed on low-capability CPUs. By using energy ratio calculation in frequency domain instead of full average value computation, the system achieves gain control functionality on disposable or low-cost processing units without requiring high-end CPU capabilities
Solution Approach 2:
The patent substitutes the mechanical computation of average value with a mathematical transformation approach. By using Fast Fourier Transform to convert to frequency domain and then calculating energy spectral density ratios, the system replaces computationally intensive time-domain averaging with more efficient frequency-domain operations that can be performed on simpler processors
Data Source
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AI summary
To perform appropriate gain control while reducing the processing load of the processing unit. A frequency domain conversion unit configured to convert a first input signal of a time domain into a second input signal of a frequency domain, the first input signal being a reference signal that is input in a first time period from a reception-side signal path through which a received signal is transmitted to a speaker provided in a terminal; a gain determination unit configured to calculate a first gain based on the second input signal; and a gain multiplication unit provided in the reception-side signal path, and configured to multiply the received signal by the first gain are included. The reference signal is a signal after the received signal is multiplied by the first gain by the gain multiplication unit.