Electronics (price negotiable)

EENG 3306 Extra Credit

Design a triangle-to-sine converter and validate its performance with Multisim. Submit (a) your calculations, (b) hard copy of your Multisim schematic, (c) Multisim transient analysis showing both the triangle input and “sinusoidal” output voltages, and (d) the results of Multisim Fourier analysis showing THD.

Maximal credit is 25 points.

There are two methods for designing the nonlinear triangle-to-sine converter.

1. Assume the maximum value of the sine wave is 1.2V (two diode potentials using the constant-voltage model of a silicon diode). Match the slope of the triangle wave vtri () to that of the sine wave vs() at  = 0; this allows you to compute the maximal value Vtri of the triangle wave. Then match the slope of the sine wave to that of the triangle wave multiplied by Rb /(Ra + Rb) when the triangle wave voltage reaches Vtri/2. This allows you to compute the ratio of the resistors.

2. Assume that the points of inflection of the piecewise-linear transfer characteristic occur at 29 (vs() = 0.6V) and 73 (vs() = 1.2V). Use the first point of inflection to determine the maximal value Vtri of the triangle wave and use the change in vs relative to the change in vtri between 29 and 73 to calculate the ratio of the resistors.

V1

-2 V 2 V

10usec 1msec

D1

1N4148

D2

1N4148

D3

1N4148

D4

1N4148

D5

1N4148

D6

1N4148

Ra

Rb

0

Vtri

Vs

3

00

00

45