TI TMS320VC5505 数字听诊器解决方案
TI 公司的数字听诊器解决方案是采用TMS320VC5505 DSP医疗开发套件来实现的.主要的元件是捕捉心肺声音的传感器,以及听诊的数字化和数字处理,以降低噪音,滤波和放大.此外还包括了心率检测和心脏缺陷检测的算法.电源和电池管理是该手提诊断设备的关键,主要的设计都采用超低功耗和高效率驱动,以延长电池寿命.本文介绍了数字听诊器总体方框图, 数字听诊器前端方框图, 增益为31的前置放大器, 一阶低通滤波器,以及TLV320AIC3254方框图和TMS320VC5505 DSP 与TLV320AIC3254间接口方框图, 数字听诊器前端板电路图和材料清单(BOM).
Digital Stethoscope Implementation on the TMS320VC5505 DSP Medical Development Kit (MDK)
The main elements of a Digital Stethoscope are the sensor unit that captures the heart and lung sounds (also known as auscultations), digitization, and digital processing of the auscultations for noise reduction, filtering and amplification. Algorithms for heart rate detection and heart defect detection may also be included.
Power and Battery Management are key in this ultra-portable diagnostic tool, where key design considerations are ultra-low power consumption and high efficiency driven by the need for extended battery life, and high precision with a fast response time allowing quick determination of the patient’s health status. Additional requirements may drive the need for recording the auscultations, cabled or wireless interfaces for transmission of the auscultations. Also, to enable ease of use, features like touch screen control and display backlighting are key to usability of the device. Adding all these features without significantly increasing power consumption is a huge challenge. Texas Instruments portfolio of Processors, Instrumentation and Buffer Amplifiers, Power and Battery Management, Audio Codecs, and both wired and wireless interface devices provides the ideal tool box for Digital Stethoscope applications.
The common core subsystems of a Digital Stethoscope are:
Analog Front-End/Sensor Interface and Codec
Auscultations signal input is amplified and then digitized by the Audio Codec. Auscultations signal after being digitized and subjected to signal processing, is converted to analog and sent to the stethoscope earpiece.
Low Power Processor
Processors capable of executing all of the digital stethoscopes signal processing including key functions such as noise reduction, algorithms for heart rate detection, and heart defect detection while maintaining a very low constant current draw from the battery are good fit. The ability to control interfacing with memory and peripheral devices is also helpful. Given the nature of the device, processors that can manage the digital display and keyed functions allowing auscultation waveforms to be displayed and manipulated without additional components are ideal.
Data Storage and Transmission
The auscultations can be recorded on MMC/SD card, or on a USB device. It can also be transmitted via wireless capability such as Bluetooth.
Digital Stethoscope Medical Development Kit
TIs TMS320VC5505 evaluation module together with TIs digital stethoscope analog front-end module make up the new C5505 DS Medical Development Kit (MDK) provides developers access to a development tool set that offers a complete signal chain solution along with software to save months of development time and for portable patient monitoring applications that demand battery efficiency.
A number of emerging medical applications such as electrocardiography (ECG), digital stethoscope, and pulse oximeters, require DSP processing performance at very low power. The TMS320VC5505 digital signal processor (DSP) is ideally suited for such applications. The VC5505 is a member of TIs C5000™ fixed-point DSP platform. To enable the development of a broad range of medical applications on the VC5505, Texas Instruments has developed an MDK based on the VC5505 DSP. A typical medical application includes:
An analog front end, including sensors to pick up signals of interest from the body
Signal processing algorithms for signal conditioning, performing measurements and running analytics on measurements to determine the health condition
User control and interaction, including graphical display of the signal processing results and connectivity to enable remote patient monitoring The MDK is designed to support complete medical applications development. It includes the following elements:
Analog front-end boards (FE boards) specific to the key target medical applications of the VC5505 (ECG, digital stethoscope, pulse oximeter), highlighting the use of the TI analog components for medical applications
VC5505 DSP evaluation module (EVM) main board
Medical applications software including example demonstrations
The front-end board contains the following stages:
Low pass filter
AC coupling block
Digital stethoscope analog front-end module can be used with C5505 EVM to make up the C5505 DS MDK that offers a complete signal chain solution along with software
图8. VC5505 DSP 和TLV320AIC3254间接口方框图