Clock Control Circuit for OFDM Spread Spectrum Interference
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Solution Overview
Problem
In digital wireless communication using OFDM, spread spectrum clocks cause interference between sub-channels due to peak spectrum occurrences, leading to degraded reception quality, and increasing spread frequency complicates accurate control and energy dispersion, while lowering spread frequency increases interference and degrades reception quality.
Innovation Solution
A clock control circuit and method that disperses harmonics of a clock signal and controls the amplitude based on spread frequency and width to reduce interference, using a demodulation device and spread spectrum technique to manage the spread spectrum clock signal, thereby minimizing peak interference and improving reception quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If spread frequency is raised to increase frequency intervals, then interference between sub-channels is reduced, but accurate control of spread width becomes more difficult and energy dispersion decreases causing high peak positions
Solution Approach 1:
The patent changes the parameter of spread frequency from high to low values. By lowering the spread frequency, the system achieves easier accurate control of spread width and better energy dispersion, while still reducing sub-channel interference through optimized spread spectrum application.
Solution Approach 2:
The patent dynamically adjusts the spread spectrum parameters based on communication conditions. By making the spread frequency and width adjustable rather than fixed, the system can optimize performance for different scenarios, achieving both accurate control and effective interference reduction.
2Object-affected harmful factors
If spread frequency is raised to increase frequency intervals, then interference between sub-channels is reduced, but energy dispersion decreases causing high peak positions
Solution Approach 1:
The patent changes the parameter of spread frequency from high to low values. This parameter change improves energy dispersion across the frequency spectrum, preventing energy concentration at specific peaks while still achieving effective interference reduction between sub-channels.
3Loss of energy
If spread frequency is lowered to increase energy dispersion, then peak positions are reduced, but interference to sub-channels increases and reception quality degrades
Solution Approach 1:
The patent optimizes the spread frequency parameter to a specific low value that achieves sufficient energy dispersion. This optimized parameter setting provides the right balance between energy dispersion and interference reduction, maintaining good reception quality.
Solution Approach 2:
The patent employs feedback mechanisms to monitor reception quality and adjust spread spectrum parameters accordingly. This feedback control allows the system to maintain optimal performance by adapting to changing communication conditions and minimizing interference to sub-channels.
4Object-generated harmful factors
If spread spectrum is applied to lower peak spectrum values, then EMI regulation is satisfied, but peak occurrences remain at each spread frequency period causing sub-channel interference
Solution Approach 1:
The patent changes the spread frequency parameter to a low value that enables effective energy dispersion. This parameter change transforms the spectrum characteristics so that peak values are reduced and energy is dispersed, simultaneously preventing sub-channel interference.
Solution Approach 2:
The patent optimizes the periodic characteristics of the spread spectrum signal by adjusting the spread frequency. This creates a periodic pattern that avoids aligning with sub-channel frequencies, thereby reducing interference while maintaining the peak-reduction benefits of spread spectrum.
Data Source
AI summary
A clock control circuit includes a clock controller which disperses a harmonic of a clock signal in a used frequency band of a reception signal and controls an amplitude of a harmonic remaining in the used frequency band after the dispersion on a basis of a spread frequency used for the dispersion and a spread width of the harmonic.