AN206

Vishay Siliconix

Document Number: 70604

10-Aug-99

www.vishay.com

S FaxBack 408-970-5600

6-3

FIGURE 4. Saturated Oxygen Simulation Circuit

DG406

From mC

Monitor

FIGURE 5. Pulse Rate Simulator

Clock

Counter

Programmable

From mC

Frequency

Out to

Monitor

The pulse rate parameter was simulated by varying the

frequency of a square wave obtained from a programmable

timer/counter. The timer/counter was programmed using

some of the microcontroller I/O lines. The square wave

frequency represents the patient’s pulse rate.

Conclusion

The finished simulator met all design goals. The DG406

worked as documented in the Vishay Siliconix data book.

Although this design used lower resistor values and digital pots

other less sensitive designs.

The

critical

components

in

this

design

were

the

microncontroller for its speed and numerous on-board

digital potentionmeters.

Considerable

time

was

spent

shopping around for these three devices. Viewing from the

better than expected results of the overall design, it is obvious

that the time spent in search of these devices was well worth

it.