Wideband RF Transmitter With Digital Harmonic Suppression
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Solution Overview
Problem
Existing wireless communication technologies face challenges in efficiently transmitting wideband RF signals due to elevated signal harmonics, which can lead to regulatory issues, increased complexity, and reduced power efficiency, particularly in systems with simultaneous radio operations.
Innovation Solution
The implementation of a digital-polar-Tx technique that generates wideband RF signals by combining phase-shifted versions of a modulated signal to suppress harmonics, such as odd harmonics, without the need for external filters, thereby maintaining power efficiency and reducing system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional wideband RF signal transmission is used, then signal bandwidth is achieved, but elevated harmonics cause regulatory issues and increased complexity
Solution Approach 1:
The patent segments the wideband RF signal into multiple narrowband signals, processes each separately through independent RF chains with different center frequencies, and then combines them. This segmentation allows each narrowband signal to be processed with simpler filtering while achieving the overall wideband effect, thereby reducing the complexity of individual processing stages.
Solution Approach 2:
The patent introduces an intermediary digital signal processing stage that combines the narrowband signals before final RF transmission. This intermediary processing layer enables harmonic suppression through digital filtering and signal combination techniques, reducing the need for complex analog filtering hardware in the RF path.
2Reliability
If external filters are added to suppress harmonics, then regulatory compliance is achieved, but power efficiency decreases and complexity increases
Solution Approach 1:
The patent applies preliminary harmonic suppression through digital signal processing before the signal reaches the power amplifier and external filters. By suppressing harmonics in the digital domain beforehand, the patent reduces the burden on external analog filters and minimizes power losses that would occur with aggressive analog filtering after amplification.
Solution Approach 2:
The patent substitutes mechanical/analog filtering components with digital signal processing techniques for harmonic suppression. This replacement eliminates the need for complex external filter hardware and reduces power consumption associated with analog filtering stages, while maintaining regulatory compliance.
3Object-generated harmful factors
If external filters are used for harmonic suppression, then harmonics are reduced, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex analog filtering hardware with digital signal processing algorithms for harmonic suppression. The digital processing stage performs frequency domain analysis and selective filtering of harmonic components, achieving effective suppression without requiring multiple external analog filters, thereby reducing device complexity and cost.
4Object-generated harmful factors
If narrowband operations are used, then harmonic issues are reduced, but bandwidth efficiency decreases
Solution Approach 1:
The patent merges multiple narrowband signals with different center frequencies through digital signal processing to create an effective wideband transmission. By combining these segmented narrowband signals constructively, the patent achieves both the harmonic reduction benefits of narrowband operations and the bandwidth efficiency of wideband transmission.
Solution Approach 2:
The patent transitions from a single-frequency narrowband approach to a multi-dimensional wideband approach by introducing the frequency dimension through multiple narrowband carriers. This dimensional expansion allows the system to achieve wideband throughput while maintaining the harmonic control advantages of narrowband processing in each frequency dimension.
Data Source
AI summary
For example, a transmitter, e.g., for a wireless communication device, may be configured to transmit a wideband Radio Frequency (RF) Transmit (Tx) signal having a wide bandwidth of at least 80 Megahertz (MHz). For example, the transmitter may be configured to generate the wideband RF Tx signal having the wide bandwidth based on a baseband signal. The transmitter may be configured to generate the wideband RF Tx signal including a suppressed third harmonic and a suppressed fifth harmonic.