Dynamic Clock Control for EMI in Wireless Transceivers
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Solution Overview
Problem
The integration of RF, BB, and PMU components in a single chip for mobile phones leads to significant EMI issues due to clock and data activity-related frequency spurs from digital peripherals, which cannot be effectively addressed by existing techniques like Time Division Isolation, especially in full-duplex 3G communications, resulting in interference with both the phone's RF receiver and neighboring devices.
Innovation Solution
A wireless communication apparatus with a centralized clocking system controlled by a Use Case Manager (UCM) that dynamically adjusts the clocking frequencies of peripherals like DDR memory, cameras, and USB interfaces based on contextual analysis of the Tx carrier frequency, power, and operational mode to prevent spurs from interfering with the RF transmission and reception bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If RF, BB, and PMU components are integrated in a single chip, then manufacturing cost is reduced, but EMI interference from clock and data activity increases
Solution Approach 1:
The patent implements dynamic clock frequency adjustment where the clocking frequency of digital peripherals is varied based on the operational context. The Use Case Manager adjusts clock frequencies to push modulated clock spurs out of the receive band, allowing the system to adaptively manage EMI interference while maintaining integration benefits.
Solution Approach 2:
The patent changes the clock frequency parameter of digital components dynamically. By adjusting the clocking frequency according to the Tx carrier frequency and operational mode, the system modifies the spectral content of clock spurs to avoid interference with the RF receiver, thus resolving the EMI issue while preserving the integrated architecture.
2Object-generated harmful factors
If Time Division Isolation is used to separate RF and digital operations, then EMI interference is reduced, but full-duplex 3G communication capability is lost
Solution Approach 1:
Instead of static time division isolation, the patent employs dynamic clock frequency adjustment that adapts to full-duplex operation requirements. The Use Case Manager continuously monitors the operational context and adjusts clock frequencies to prevent spur interference while allowing simultaneous TX and RX operations, thus maintaining full-duplex capability.
Solution Approach 2:
The patent dynamically changes the clock frequency parameter based on the specific communication mode and carrier frequency. This allows the system to accommodate full-duplex 3G operations by adjusting clock spurs to avoid the receive band, eliminating the need for time division isolation while preserving EMI protection.
3Device complexity
If clocking frequency of digital peripherals is fixed, then device complexity is reduced, but EMI compliance with ETSI specifications cannot be ensured
Solution Approach 1:
The patent introduces a dynamic clocking system where frequencies are adjusted based on operational context to ensure ETSI compliance. The Use Case Manager monitors the Tx carrier frequency and operational mode, then adjusts peripheral clock frequencies accordingly, adding complexity only where needed to maintain regulatory compliance.
Solution Approach 2:
The patent implements variable clock frequency operation that adapts to different communication scenarios. By changing the clocking frequency parameter based on the specific Tx carrier and mode, the system ensures that modulated clock spurs remain outside the receive band, guaranteeing ETSI compliance while maintaining manageable system complexity through centralized control.
Data Source
AI summary
A wireless telecommunication apparatus comprising—a baseband for the purpose of generating and receiving base-band signals; —a RF transceiver for the purpose of transmitting and receiving a RF signals, —at least one centralized clock derived from at least one central oscillator; —at least one individual element located within said apparatus and having a EMI coupling with said RF transceiver, and which clocking is likely to generate spurs being modulated with the Tx carrier of said RF transceiver; Characterized in that it further includes: —a least one controllable clocking system for said at least one individual element; —a general control unit (UCM) for the purpose of performing a contextual analysis of the current mode of operation of said wireless telecommunications and, in response to said contextual analysis, for determining a clocking frequency which results in modulated Tx clock spurs out of the receive bands.