RF Receiver Dynamic Frequency Planning for Spur Reduction
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Solution Overview
Problem
Integrated RF receivers face issues with unwanted signal coupling due to magnetic and electrical interactions between circuits, leading to signal distortion and artifacts, which traditional layout strategies and ground rings cannot fully eliminate.
Innovation Solution
The RF receiver employs dynamic frequency planning, specifically through a TV tuner chip that adjusts its clock synthesizer's frequency to minimize coupling effects by considering direct coupling, spur generation, and sub-harmonic mechanisms, allowing operation within a range that reduces harmful interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional layout strategies and ground rings are used to reduce coupling, then physical separation and conductor length are reduced, but signal distortion and artifacts from magnetic and electrical coupling cannot be completely eliminated
Solution Approach 1:
The patent changes the frequency parameter of the clock signal dynamically based on the selected channel. By adjusting the clock frequency, the system moves the operating point away from frequencies that cause harmful coupling and spur generation, thereby reducing signal distortion without requiring more complex physical layout strategies
2Ease of manufacture
If integrated circuit technology is used to combine circuits on-chip, then cost is reduced, but magnetic and electrical coupling between circuits increases
Solution Approach 1:
The patent employs dynamic frequency planning that adjusts the clock synthesizer frequency based on the selected channel. This parameter change allows the integrated circuit to operate at frequencies that minimize coupling effects between on-chip circuits, maintaining cost-effectiveness while reducing signal distortion from magnetic and electrical coupling
Solution Approach 2:
The system dynamically adjusts the clock frequency based on channel selection rather than using a fixed frequency. This dynamic adaptation allows the integrated circuit to optimize its operating parameters in real-time, reducing coupling effects between circuits while maintaining the benefits of integration
3Object-affected harmful factors
If a fixed clock frequency is used, then device complexity is reduced, but spur generation and signal distortion increase due to coupling at specific frequencies
Solution Approach 1:
The patent implements frequency planning that changes the clock frequency parameter based on the selected channel. This approach reduces spur generation and signal distortion by avoiding problematic frequencies, while the complexity is managed through structured frequency selection algorithms rather than hardware complexity
Data Source
AI summary
A radio frequency (RF) receiver comprises an analog receiver, a digital processor, a clock synthesizer, and a microcontroller. The analog receiver has an input for receiving an RF input signal, and an output for providing a digital intermediate frequency (IF) signal. The digital signal processor has a first input for receiving the digital IF signal, a second input for receiving a clock signal, and a signal output for providing an IF output signal. The clock synthesizer has an input for receiving a clock control signal, and an output for providing the clock signal. The a microcontroller has an input for receiving a channel selection signal, wherein the microcontroller provides the clock control signal to control a frequency of the clock signal dynamically in response to a channel selection input to reduce interference of sub-harmonics created by the clock signal on the analog receiver.