Single PLL Carrier Signal Generation for Crosstalk Reduction
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Solution Overview
Problem
Circuits for generating multicarrier signals using multiple phase locked loop (PLL) circuits suffer from crosstalk issues, leading to reduced performance and unwanted spectral emissions.
Innovation Solution
Frequency shifting the output signal of a single PLL circuit to generate multiple carrier signals at different frequencies, which are then modulated to avoid crosstalk and improve signal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple PLL circuits are used to generate multiple carrier signals, then each carrier signal can be generated independently, but crosstalk occurs leading to reduced performance and unwanted spectral emissions
Solution Approach 1:
The patent merges multiple carrier signal generation functions into a single PLL circuit. The single PLL generates one carrier signal that is then distributed to multiple modulators, eliminating the need for multiple separate PLL circuits and thereby removing the source of crosstalk between independent PLL circuits while maintaining independent modulation capabilities.
Solution Approach 2:
The patent segments the carrier signal generation function from the modulation function. The single PLL circuit generates the carrier signal, which is then segmented and distributed to multiple modulators that perform the actual modulation. This separation allows independent modulation of each carrier signal without interference from multiple PLL circuits.
2Adaptability or versatility
If multiple PLL circuits are used to generate multiple carrier signals, then each carrier can be modulated independently, but the device complexity increases
Solution Approach 1:
The patent combines multiple carrier generation functions into a single PLL circuit, reducing device complexity. The single PLL output is then distributed to multiple modulators, preserving independent modulation capability while eliminating redundant PLL circuits and reducing overall system complexity.
Solution Approach 2:
The single PLL circuit serves multiple functions by generating carrier signals for multiple modulators. This multi-functional approach allows one PLL to replace what would traditionally require multiple PLL circuits, reducing device complexity while maintaining versatility.
3Adaptability or versatility
If multiple PLL circuits are used to generate multiple carrier signals, then carrier signals at different frequencies can be generated, but power amplifier current consumption increases
Solution Approach 1:
The patent merges multiple carrier generation functions into a single PLL, which reduces the number of power amplifiers needed. By using one PLL output for multiple modulators, the system reduces power amplifier current consumption while maintaining the ability to generate carrier signals across a wide frequency range through the single PLL's frequency control.
Solution Approach 2:
The single PLL circuit provides universal carrier generation for multiple modulators operating at different frequencies. This multi-functional carrier source reduces the overall power consumption of the system compared to using separate PLL circuits for each frequency, as the single PLL can be optimized and shared across all modulation paths.
Data Source
AI summary
A method and an apparatus provide a plurality of modulated signals by frequency shifting an output signal of a carrier signal generation circuit for obtaining a first carrier signal and a second carrier signal, and by modulating the first and second carrier signals.