Re-clocking Circuit Devices for Spectral Null Generation
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Solution Overview
Problem
Digital signals communicated across communication links radiate spectral energy at various radio frequencies, causing electromagnetic interference (EMI) that impairs signal-to-noise ratio and increases error rates in nearby analog receiver circuitry, particularly when these receivers are tuned to specific RF channels.
Innovation Solution
Circuit devices and methods that alter the edge timing of digital data streams to produce a modulated output signal with spectral nulls at desired frequencies and their harmonics, reducing radiated interference without changing the average data rate, by using edge adjustment circuitry to re-clock the signals with a second clock rate selected to correspond to the RF frequency of interest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If digital signals are communicated across communication links, then data transmission is achieved, but radiated spectral energy causes electromagnetic interference with nearby analog receiver circuitry
Solution Approach 1:
The patent applies periodic action by modulating the digital signal transitions to occur at periodic intervals that create spectral nulls at specific radio frequencies. By controlling the timing of edge transitions in a periodic manner, the signal radiates less energy at targeted frequencies while maintaining data transmission functionality.
Solution Approach 2:
The patent changes the temporal parameters of the digital signal by altering the timing of edge transitions. By adjusting when transitions occur relative to a clock signal, the signal's spectral characteristics are modified to create nulls at interfering frequencies, thereby reducing electromagnetic interference without changing the data rate.
2Object-affected harmful factors
If spectral nulls are introduced at desired frequencies to reduce interference, then electromagnetic interference is reduced, but the signal requires modulation which may complicate the circuit
Solution Approach 1:
The patent introduces a clock signal as an intermediary to control the timing of transitions. This clock signal serves as a mediator that coordinates when transitions occur, creating spectral nulls at desired frequencies. The clock signal simplifies the control logic by providing a regular timing reference that automatically generates the desired spectral characteristics.
3Object-affected harmful factors
If edge timing is altered to produce spectral nulls, then radiated interference is reduced, but the transition timing of the signal changes
Solution Approach 1:
The patent uses periodic action by synchronizing transition timing to a clock signal with a specific frequency. This periodic timing control ensures that transitions occur at intervals that create spectral nulls at interfering frequencies, reducing radiated energy while maintaining predictable and controllable edge timing behavior.
Data Source
AI summary
Embodiments include circuit devices and methods for re-clocking an input signal. In an embodiment, a circuit device includes a data storage element having a data input to receive a digital data stream having a first clock rate and including a clock input to receive a clock signal having a second clock rate. The data storage element further includes logic to adjust edge timing of transitions within the digital data stream based on the clock signal to produce a modulated output signal having a power spectrum with spectral nulls at a desired frequency and its harmonics without changing an average data rate.