CARDIAC PACING AND DEFIBRILLATION - Design and Development of Medical Electronic Instrumentation - page 409

1.4

1.2

1

0.8

0.6

0.4

DVM Reading (V)

0.2

0

0 500 1000 1500 2000 2500

Decade Box Setting ( Ω )

Figure 8.28 The intracardiac impedance sensor produces an output voltage that follows this graph as a function of impedance (resistive).

+Vsrc

S1

Coupling

S3

OUT

Ca1

LEAD

C

S5 S6

DIFF

HEART

Ca2

S4

S/H

S2

-Vsrc

Figure 8.29 Implementations of the same concept can be done in integrated circuits without the need for operational ampli fi ers through

the use of a switched-capacitor di ff erential to single-ended converter, which also acts as a sample-and-hold circuit.

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