Human Body Pulse Receiver Circuit for Sensitive Single-Electrode Detection
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Solution Overview
Problem
Existing communication technologies using the human body as a data transmission medium face limitations in reception sensitivity and require high-speed comparators with DC bias and threshold voltages, while also consuming high power and being unsuitable for single transmission lines.
Innovation Solution
An apparatus employing a bias circuit for setting DC bias, a wide-band pre-amplifier for high voltage gain, a Schmitt trigger for symmetrical triggering, and an inversion buffer to convert wide-band pulse signals into digital signals using 50-Ω impedance matching and symmetrical threshold voltages, allowing for low power consumption and high-speed communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a comparator-based pulse receiver is used for AC coupled interface, then the circuit configuration is simple and power consumption is low, but the input pulse signal must have a DC bias and threshold voltages are required, and reception sensitivity is limited due to restrictive hysteresis characteristics
Solution Approach 1:
The patent changes the operating parameters by using a differential amplifier instead of a comparator, enabling the circuit to operate without DC bias and threshold voltages. The differential amplifier's continuous linear operation mode replaces the comparator's digital switching mode, fundamentally changing the parameter set and eliminating the need for hysteresis and threshold voltages, thereby improving reception sensitivity while maintaining reasonable circuit complexity
Solution Approach 2:
The patent substitutes the comparator-based digital detection mechanism with an analog differential amplification mechanism. This replacement eliminates the need for hysteresis characteristics and threshold voltages, allowing the circuit to detect weaker signals with higher precision while maintaining simplicity through the use of standard operational amplifier circuits
2Measurement precision
If high-speed comparators with DC bias and threshold voltages are used to improve reception sensitivity, then reception sensitivity increases, but power consumption increases and the system becomes unsuitable for single transmission lines
Solution Approach 1:
The differential amplifier circuit serves itself by generating the necessary bias conditions internally through its symmetric structure and feedback mechanisms. The circuit automatically establishes its operating point without requiring external DC bias voltages or threshold voltage references, thereby eliminating the power-consuming components while maintaining high reception sensitivity through its inherent differential operation
Solution Approach 2:
The differential amplifier performs multiple functions simultaneously: it provides signal amplification, establishes its own bias conditions, and operates on single-ended transmission lines. This multi-functionality eliminates the need for separate biasing circuits and threshold voltage generators, reducing overall power consumption while maintaining high reception sensitivity
3Adaptability or versatility
If AC coupled interface technology is used for human body communication, then the interface can be implemented with existing capacitively coupled designs, but DC signals and low-frequency signals below 10 kHz cannot be transmitted through the human body
Solution Approach 1:
Instead of trying to pass DC and low-frequency signals through the capacitive coupling barrier, the invention inverts the approach by using a differential amplifier that can detect and amplify the AC-coupled signal directly without requiring DC passage. The differential amplifier's common-mode rejection ratio (CMRR) allows it to extract the differential signal component while rejecting the blocked DC component, effectively working around the capacitive coupling limitation
Data Source
AI summary
Disclosed herein is an apparatus for receiving a wide-band pulse signal in a communication channel using a human body. When a weak wide-band pulse signal, which is output from a communication channel using a human body as a data transmission medium, is restored to a digital signal, it is possible to accomplish low power consumption and high data transmission rate using a wide-band symmetrical triggering technology using 50-Ω impedance matching, wide-band amplification and symmetrical threshold voltages. In addition, since only a single signal electrode is used, it is possible to provide an apparatus having usability, wearability and miniaturization. In addition, it is possible to remove necessities of an external reference voltage to reduce area consumption and to simply adjust a feedback resistor to easily adjust the reception sensitivity according to a communication distance.