Digital Modulator Using Time Interleaving for Wider RF Bandwidth
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Solution Overview
Problem
Existing digital modulators using phase-locked digital modulation schemes struggle to achieve wider signal bandwidth due to fixed clock frequencies, leading to increased noise and complexity in design, especially when trying to handle 5G wideband signals.
Innovation Solution
A digital modulator configuration that includes a polar converter, RF phase signal generator, rectangulating unit, time interleaver, ΔΣ modulator, and selector, which generates phase and amplitude signals, converts the RF phase signal to a rectangular shape, and performs time interleaving and ΔΣ modulation using the rectangular RF phase signal to achieve wider bandwidth with simpler components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a phase-locked digital modulation scheme is used with a fixed clock frequency, then the system can operate with simple components, but the signal bandwidth is limited and cannot be widened
Solution Approach 1:
The patent applies dynamics by making the clock frequency adjustable rather than fixed. The ΔΣ modulator's clock frequency can be dynamically changed based on the required signal bandwidth, allowing the system to adapt to different bandwidth requirements while maintaining the simplicity of the phase-locked modulation architecture.
Solution Approach 2:
The patent changes the clock frequency parameter of the ΔΣ modulator to achieve different signal bandwidths. By adjusting this key parameter, the system can handle 5G wideband signals without changing the overall modulator architecture, thus maintaining simplicity while improving adaptability.
2Adaptability or versatility
If the clock frequency is increased to achieve wider bandwidth, then the signal bandwidth increases, but the signal-to-noise ratio degrades
Solution Approach 1:
The patent uses periodic action through the ΔΣ modulation technique, which spreads quantization noise over a wide frequency range. By using a rectangular RF phase signal with periodic transitions to control the ΔΣ modulator, the system achieves wide bandwidth while maintaining signal-to-noise ratio through noise shaping and filtering characteristics of the periodic modulation process.
3Ease of operation
If orthogonal modulation with N-valued signals is used, then the signal can be modulated, but the mixer configuration becomes complicated
Solution Approach 1:
The patent extracts the complexity from the mixer configuration by using a simplified approach: generating a rectangular RF phase signal that directly controls the ΔΣ modulator. This eliminates the need for complex N-valued signal distribution and multiple mixers, reducing the mixer configuration to a simple selector that chooses between I and Q channel outputs based on the rectangular phase signal.
Data Source
AI summary
A digital modulator according to the present disclosure includes a polar converter that generates a phase signal and an amplitude signal from a baseband signal, an RF phase signal generator that generates an RF phase signal on the basis of the phase signal, a rectangulating unit that generates a rectangular RF phase signal by converting the RF phase signal into a rectangular shape, a time interleaver that time interleaves the amplitude signal and outputs first and second time interleaved signals, a ΔΣ modulator that ΔΣ modulates the first and second time interleaved signals on the basis of the rectangular RF phase signal and outputs first and second ΔΣ modulated signals, and a selector that selects and outputs one of the first and second ΔΣ modulated signals on the basis of the rectangular RF phase signal.