PRACTICAL: 4

Aim: STUDY OF ECG SIMULATOR.

Material required-

[1] Matrix trainer kit - ECG SIMULATOR

[2] CRO

Procedure:

Setup –

|1] Keep the POWER switches in off condition.

[2] Connect power chord to mams (230 volt a. c.).

[3] Select Required Heart rate by JUMPERS (JI-30PPM. J2-60PPM, J3-120PPM or

J4- 1SOPPM) at B Position (any one at a time)

[4]Put on the trainer kit & CRO.

[5]Observe tire output on CRO at o/p terminal T1, T2, T3, TS, T6 T7, T9, T10, T11,

T12 w.r.t. T8

[6]Note all the observation.

[7] Repeat step 7 for other heart rate.

Reading:

Sr. No Heart rate selected Oral count of I .ED Blinks for 15 second X 4

Students should note their own observation.

ECG SIMULATOR

INTRODUCTION:

A system is able to produce signals as some other system is known as simulator.

Biomedical simulators are those are producing artificial signal, like natural part

produce in live body. Like ECG Simulator produce signal as hart in human body.

Artificially by means of semiconductors & electronics components like resistance,

capacitance & inductor in a complete circuit form can produce Electrocardiogram

(ECG).

Fig.4.1: heartbeats from ECG simulator

Each part of the tracing has a lettered name:

1. P wave - coincides with the spread of electrical activity over the atria and the

beginning of its contraction.

2. QRS complex - coincides with the spread of electrical activity over the

ventricles and the beginning of its contraction.

3. T wave – coincides with the recovery base of the ventricles.

Fig.4.2: Circuit diagram of ECG simulator

Circuit Theory :

ECG Simulator consists of Kate generator, Complex clock generator. Complex

generator, scaling network, integrator S: lead attenuator it also having an addition

transistor amplifier for Simulation of GRS pulse. This amplifier derives LED for

visual sense for QRS pulse. It also drives Buzzer of audio whenever QRS occurred.

Rate Generator:

This an astable Multivibrator based on CMOS NAND gate N1 &. N2, C1 R1 or C1 R2

or C1 R3 or C1 R3 produce repeating rate of 3OBPM or 60BPM or 120BPM or

180BPM Output of rate generator trigger complex clock generator. Only the duration

of rate generator m which their o/p high enables the complex clock generator circuit.

Complex clock generator:

This also an astableMultivibrator based on CMOS NAND gate N3 &. N4, It o/p

frequency is constant due to fixed C2 RS & RO frequency responsible component.

Output of complex generator is 10 complex of successive pulse by Ripple counter

4017. Last pulse of these 10pulse train reset rate generator circuit to produce zero.

This o/p of rate generator will remain low for the time constant set by C1 R1 or C1 K2

or C1 R3 or C1 R3.

Scaling Network:

This is consists of ten different value resistance. This resistance add all ten pulse to

produce ECG complex. The output of this resistive network is as digitized ECG in

nature.

Integrator circuit:

R23, R22, C6, C4, * C3 integrate DIGITIZED like ECG waveform from scaling

network to produce good actual like ECG complex. C5 block Dc signal for scaling

network.

Lead attenuators:

Lead attenuators are resistive network attenuate ECG complex in different level, so

o/p of this circuit produce actual amplitude of all lead form any calibrated ECG

system. In this way we can have actual look like ECG complex o/p & all lead out form

ECG simulator.

Conclusion: