Phase Modulation Edge Suppression Circuit
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Solution Overview
Problem
Direct digital modulation circuitry faces speed constraints due to phase jumps in phase-modulated signals, which can result in reduced distances between signal edges, necessitating increased speed in phase modulation circuitry, but existing solutions like frequency limitation degrade error vector magnitude (EVM) and adjacent channel leakage ratio (ACLR).
Innovation Solution
The method involves suppressing irrelevant edges in phase-modulated signals by analyzing and comparing transition distances to a threshold, removing edges with distances less than the threshold without affecting the signal quality, thereby relaxing speed requirements for phase modulation circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If phase modulation creates phase-jumps in the carrier-signal, then phase modulation information can be conveyed, but distance between signal edges is reduced requiring increased speed in phase modulation circuitry
Solution Approach 1:
The patent extracts and removes irrelevant edges from the phase-modulated signal that do not carry useful modulation information. By identifying and eliminating these redundant edges through edge detection and comparison logic, the circuit maintains phase modulation information while reducing the total number of edges that require processing, thereby lowering the speed requirements of the phase modulation circuitry
Solution Approach 2:
The patent changes the parameter of edge density by selectively removing edges based on comparison with adjacent edges. By comparing the phase difference of each edge with its neighbors and suppressing edges that fall within a threshold range, the system transforms a high-density edge stream into a reduced-density stream that maintains information integrity while reducing processing speed demands
2Speed
If frequency limitation is applied to reduce variation of temporal distances, then speed constraints are relaxed, but error vector magnitude (EVM) and adjacent channel leakage ratio (ACLR) deteriorate
Solution Approach 1:
Instead of applying frequency limitation that degrades signal quality, the patent extracts only the harmful aspect (irrelevant edges) while preserving the useful signal components. By removing specifically identified irrelevant edges through comparison logic rather than blunt frequency limiting, the system relaxes speed constraints without deteriorating EVM or ACLR
Solution Approach 2:
The patent applies local quality by treating different edges differently based on their individual characteristics. Rather than uniformly limiting all frequencies, each edge is locally evaluated against its neighbors and selectively suppressed only if it meets the irrelevant edge criteria, thereby maintaining signal quality while reducing processing demands
Data Source
AI summary
This application discusses, among other things, apparatus and methods for suppressing irrelevant edges of a phase modulated signal. In an example, a method can include receiving phase modulation information at a suppression circuit of a communication device, computing distances between transitions of a phase modulation signal, the phase modulation signal associated with the phase modulation information, comparing the distances to a threshold distance at a comparator of the suppression circuit, and suppressing a first transition of the phase modulation signal associated with the phase modulation information if a first distance is less than the threshold distance.