Local Oscillator Chain Selection for Spurious Harmonic Management
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Solution Overview
Problem
In multi-receiver personal mobile communication devices, strong RF fields and spurious harmonics from local oscillators interfere with co-located radio receivers, necessitating costly filters and shielding to mitigate interference.
Innovation Solution
A method and apparatus that monitor the operational state of radio receivers to customize the local oscillator chain frequency conversion, selecting configurations to place spurious harmonics outside active radio bands, thereby reducing the need for additional filtering and shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If filters and shielding are added to mitigate spurious harmonic interference, then interference between co-located radio receivers is reduced, but device cost and circuit board space increase
Solution Approach 1:
The patent implements dynamic selection of local oscillator chains based on which radio receivers are currently active. The system monitors the operational state of multiple radio receivers and dynamically switches between different LO chains to ensure that spurious harmonics do not interfere with active receivers. This dynamic adaptation eliminates the need for static filters and shielding, reducing device complexity while maintaining interference mitigation.
Solution Approach 2:
The system changes the frequency parameters of the local oscillator chains based on the operational state of radio receivers. By selecting LO chains with different frequency characteristics, the system ensures that spurious harmonics fall outside the frequency bands of active receivers. This parameter-based adaptation resolves the contradiction by eliminating the need for additional filtering components.
2Reliability
If filters and shielding are added to mitigate spurious harmonic interference, then receiver performance is improved, but manufacturing cost increases
Solution Approach 1:
The patent employs dynamic LO chain selection that adapts to the operational state of radio receivers. By dynamically switching between different LO chains, the system ensures optimal receiver performance without requiring additional filters or shielding components. This reduces manufacturing cost while maintaining reliability.
Solution Approach 2:
The system uses its own local oscillator chains to serve multiple functions: generating LO signals for frequency conversion and simultaneously avoiding interference with other receivers. The dynamic selection mechanism allows the LO subsystem to self-regulate and prevent interference without requiring separate filtering components, thereby reducing manufacturing cost while maintaining receiver performance.
3Adaptability or versatility
If multiple radio receivers operate simultaneously in close proximity, then device functionality is enhanced, but spurious harmonic interference increases
Solution Approach 1:
The patent implements a dynamic LO chain selection mechanism that monitors which radio receivers are active and automatically selects appropriate LO chains to minimize spurious harmonic generation. This dynamic adaptation allows multiple receivers to operate simultaneously without significant interference, enhancing device functionality while controlling harmful emissions.
Solution Approach 2:
The system changes the frequency parameters of different LO chains to avoid generating spurious harmonics that would interfere with other active receivers. By monitoring the operational state of multiple receivers and adjusting LO chain selection accordingly, the system enables simultaneous operation of multiple receivers with minimal interference.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach conserves costs and circuit board space by minimizing the requirement for filters and shielding, effectively managing interference between co-located radio receivers.
Implementation Method 1
spurs may be generated as unwanted byproducts of mixing and other frequency conversion operations used to convert a base oscillator signal to the required LO frequency
Implementation Method 2
spurs may be generated as unwanted byproducts of mixing and other frequency conversion operations used to convert a base oscillator signal to the required LO frequency
Data Source
AI summary
Apparatus and methods disclosed herein operate to determine a base oscillator frequency and a frequency conversion factor associated with a radio receiver local oscillator (LO). Base oscillator frequency and frequency conversion parameters are selected such that spurious harmonics created within the LO lie outside of communication bands associated with other active radio receivers substantially collocated with the LO. An LO chain including the appropriate base oscillator and frequency conversion components is selected from a switched set of base oscillator/frequency converter pairs.