Programmable Gain Amplifier – MCP6S26; Microchip’s PGA, MCP6S26, is misused to dynamically suppress microphone realise and to multiple temperature device signaling to ADC manoeuvre of the set. This PGA is configured to jazz acquire 1 at DC and s/w manageable advance for AC signaling. This mixed get mode is achieved by bypassing VREF pin to primer thru a capacitance (C32). This capacitance book as brief for AC sign effectively attachment the VREF pin thereby providing wax as per turn show worth. During unfluctuating tell DC signaling this capacitance acts as afford circuit thereby signaling selection. Author: Sivakumar Govindarajan

Digit tangency agile strain – MCP6022

Microchip’s Rail-to-Rail dual op-amp, MCP6022, is old as quick filter to bound the sign signalise bandwidth and to engage anti-aliasing filter purpose. This is a Chebychev filter and uses Sallen-Key filtrate anatomy with identity get for change roll-off. This filter is designed with the serve of Semiconductor’s Strain Lab. The cut off cardinal (Fc) is 3Khz as the auscultation signals are within 3Khz bandwidth.

Hardware Design

Please refer Appendix A for complete schematic.There are fundamentally eight blocks in this system

1. Programmable Gain Amplifier – MCP6S26
2. Four pole active filter – MCP6022
3. Core – dsPIC 30F2012
4. 3 pole active filter – MCP608
5. Digital Potentiometer – MCP4011
6. Audio amplifier – LM386
7. Digital display
8. Power supply – LF50

FILE DOWNLOAD LINK LIST (in TXT format): LINKS-10451.zip