Laboratory 4 Rev QRS Detector

Laboratory 4 Rev QRS Detector - The correct operation of...

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1 Applied Electronics Laboratory Laboratory 4 QRS Detector 1 Purpose : This lab. consists of a two week project to construct and evaluate a detector that senses the QRS complex from the ECG signal . Materials : Breadboard, signal generator, oscilloscope, power supply (P 15 volts), LF356, (up to 7), 555, diode, LED, 10 kΩ pot, assorted resistors, 10 PF and .01 PF capacitors. Alternative ADC 524 instrumentation amplifier. A block diagram of the QRS Detector is shown below. ECG Amplifier Rectifier Threshold Detector Display and driver Bandpass Filter V ECG The first stage amplifiers a two-lead ECG input signal. This stage is a differential amplifier with a high impedance input known as an “instrumentation amplifier.” It can implemented with three op amps as shown in the circuit below. Alternatively, an single chip instrumentation amplifier such as the ADC 524 can be used. + _ Op amp V out _ Op amp V in 1 R 1 R 2 + + _ Op amp V in 2 R 2 R 3 R 3 R 4 R 4 1 This is a two week laboratory.
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Unformatted text preview: The correct operation of this circuit must be demonstrated during the second week. 1 For the second stage use a resonant bandpass filter from Lab 3. Try the following component values: C = 0.1 F; R 1 = 159 k, R 2 = 22 k, and R 3 = 318 k For the third stage use the full-wave rectifier from Lab. 3. For the Threshold circuit use the Schmitt trigger from Lab 3 and a modified version of the peak detector as shown below. The pot sets the fraction of the rectified EEG peak that will be used as threshold for the QRS signal. This circuit should track amplitude changes in the ECG signal. + V in _ LF 356 300 kP 1 kP + _ LF 356 1 MP 330 kP 100 kP 1 MP 10 PF + V out Threshold Adjust For the display use the classic 555 timer configured as a monostable driving an LED. 2 V out V in 1 MP 555 2 3 8 4 1 5 6 7 +15 V LED +15 V .1 PF .01 PF 100 kP 330 P .1 PF 3...
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Laboratory 4 Rev QRS Detector - The correct operation of...

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