ASK Modulation Circuit Phase Control for EMI Suppression
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Solution Overview
Problem
In ASK modulation, it is challenging to satisfy EMI regulations due to high carrier wave irradiation, which leads to reduced transmission power and reception sensitivity.
Innovation Solution
A transmission circuit and method that incorporates an amplitude shift modulation circuit to change the amplitude of carrier waves based on transmission data and a phase control circuit to change the phase of carrier waves based on transmission data, thereby lowering the peak level of carrier wave components without affecting transmission power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If ASK modulation is used to reduce transmission circuit size and power consumption, then miniaturization and low power consumption are achieved, but carrier wave irradiation increases causing EMI regulation violations
Solution Approach 1:
The patent combines ASK modulation with phase modulation to create a hybrid modulation scheme. The amplitude shift modulation circuit modulates carrier wave amplitude according to transmission data, while the phase control circuit simultaneously modulates the phase. This merging of modulation techniques allows the system to maintain the power efficiency of ASK while introducing phase variations that reduce carrier wave irradiation peaks, thereby satisfying EMI regulations.
Solution Approach 2:
The patent changes the phase parameter of the carrier wave in addition to the amplitude parameter. By controlling both amplitude (via ASK modulation) and phase (via phase control circuit) of the carrier wave, the system transforms the single-parameter ASK modulation into a two-parameter modulation scheme. This parameter change approach reduces the peak carrier wave irradiation while maintaining transmission power efficiency.
2Object-affected harmful factors
If transmission power is lowered to satisfy EMI regulations, then EMI compliance is achieved, but reception sensitivity decreases and resistance to interfering waves weakens
Solution Approach 1:
The patent merges ASK modulation with phase modulation to create a hybrid scheme that maintains transmission power while reducing EMI. The amplitude shift modulation preserves signal strength for good reception sensitivity, while the added phase control reduces peak carrier irradiation. This combination allows simultaneous achievement of EMI compliance and maintained reception sensitivity without requiring power reduction.
3Power
If carrier wave amplitude is increased to improve transmission distance, then transmission power increases, but carrier wave irradiation peaks increase violating EMI regulations
Solution Approach 1:
The patent introduces phase as an additional controlled parameter alongside amplitude. By varying both amplitude and phase of the carrier wave according to transmission data, the system can maintain adequate transmission power levels while the phase variations prevent excessive peak irradiation. This dual-parameter control resolves the contradiction between transmission power and EMI compliance.
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 suppresses carrier wave irradiation, meeting EMI regulations without compromising transmission power, thus enhancing reception sensitivity.
Implementation Method 1
an amplitude shift modulation circuit that changes an amplitude of carrier waves based on transmission data
Implementation Method 2
a phase control circuit that changes a phase of the carrier waves based on the transmission data
Data Source
AI summary
In a transmission circuit that transmits transmission data using an amplitude shift modulation method (ASK modulation method) for changing an amplitude of carrier waves based on the transmission data or a transmission system that uses the transmission circuit, a phase of the carrier waves is changed based on the transmission data to suppress an irradiation of carrier wave components.