Trap Filter for Reducing Carrier Leakage Spurious Emissions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless communication systems face challenges in reducing spurious emissions caused by carrier leakage, particularly near frequency band boundaries, which can lead to signal interference and compliance issues with regulatory limits, while also limiting signal coverage due to reduced transmit power.
Innovation Solution
The implementation of a modulator and filter configuration in wireless communication systems that selectively removes carrier frequency components from modulated signals, allowing for increased transmit power without exceeding spurious emissions limits by enabling a trap filter for signals near frequency band boundaries and disabling it for signals within the band, thereby maximizing signal coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If transmit power is reduced to reduce spurious emissions, then spurious emissions are reduced, but signal coverage decreases
Solution Approach 1:
The patent extracts and removes the carrier frequency component from the modulated signal using a filter. This selectively eliminates the harmful carrier leakage that causes spurious emissions while preserving the modulated signal components that carry useful information, thereby reducing spurious emissions without requiring reduction of overall transmit power
Solution Approach 2:
The patent applies filtering selectively based on the transmit frequency's proximity to band edges. The trap filter is enabled only when the modulated signal's transmit frequency is within a threshold distance from a band edge, creating a localized solution that addresses spurious emissions only where they occur without affecting signal coverage in other frequency regions
2Reliability
If transmit power is reduced to comply with spurious emissions limits near band boundaries, then regulatory compliance is achieved, but signal coverage and transmission effectiveness are limited
Solution Approach 1:
The patent determines whether the transmit frequency is within a threshold distance from a band edge before transmission, and proactively enables the trap filter in advance. This preliminary detection and preparation ensures regulatory compliance is achieved before the signal is transmitted, allowing maximum transmit power to be used without risking non-compliance
Solution Approach 2:
The filter selectively removes only the carrier frequency component that causes spurious emissions, leaving the modulated signal intact. This extraction approach achieves regulatory compliance by eliminating the harmful component while preserving the useful signal, thereby maintaining productivity and signal coverage
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces spurious emissions and maintains high signal coverage by selectively addressing carrier leakage, ensuring compliance with regulatory limits without reducing transmit power.
Implementation Method 1
a trap filter configured to selectively remove a carrier frequency component from the modulated signal
Data Source
AI summary
An exemplary apparatus includes a modulator configured to modulate a data signal onto a carrier signal to generate a modulated signal having a transmit frequency within a predefined frequency range adjacent to and within a boundary of an uplink frequency band, a filter configured to at least partially remove a carrier frequency component from the modulated signal to produce a filtered modulated signal, and an antenna configured to transmit the filtered modulated signal.