Proteus VSM project

Hi everybody,

I try to conceive a schematic with proteus VSM.
I join you the proteus project file.
The problem is the following: I don't manage to get a square wave
at the output of the comparator U4.
Thanks for your help!



D.Delteil

This is a very badly drawn schematic, and makes it difficult to determine the signal flow.

What is the purpose of the 555 (U2)? Its output does not connect to the rest of the circuit.

The LM311 has an open collector output. It cannot drive the hysteresis feedback or any other linear circuit without some kind of pull up impedance.

ak

AnalogKid said:

What is the purpose of the 555 (U2)? Its output does not connect to the rest of the circuit.

Click to expand...

Nor does the micro!! Must be a work in progress....

Hello,

I hope you will read this part of schematic.

The purpose of NE555 is to make a square wave of 40 khz about.
The output (pin 3) should be wired to pin number 16 of the PIC16F84.
The enter sine of the passband filter is a 40khz sine.
The output of that sine is compared to a power supply
so as to generate a square wave but it is not the case.

Thank you for your help!