# Need help for Square Signal Comparator

#### Mr.Dido

Joined Nov 18, 2007
5
Dear all,

Hi. i have small problem. i have a switch give me output as square signal 2.7 V(p-p) when its OFF. when its ON give square signal 3.9 v(p-p). My request is to discard the small signal 2.7 V(p-p) from comparator output by using DC voltage references.

please for all who can help me, send a circuit design.

regards

#### studiot

Joined Nov 9, 2007
4,998
About your simplest solution would be a 3v6 zener in series with the switch output.

#### hgmjr

Joined Jan 28, 2005
9,027
Dear all,

Hi. i have small problem. i have a switch give me output as square signal 2.7 V(p-p) when its OFF. when its ON give square signal 3.9 v(p-p). My request is to discard the small signal 2.7 V(p-p) from comparator output by using DC voltage references.

please for all who can help me, send a circuit design.

regards
Let me see if I understand your question.

You want to monitor a signal controlled by a switch. When the switch is OFF the signal you want to monitor is 2.7v p-p. When the switch is ON the same signal changes to 3.6v p-p.

Does the 2.7V p-p signal swing between 0V and 2.7V? If not, what two voltages does it swing between? The same information on the 3.6V p-p signal would be inportant to know. Also are both signals the same frequency?

It is unclear from you description whether you want to block the 2.7V p-p signal and pass the 3.6V p-p only or just generate a logic signal that indicates that the signal is 2.7V p-p with a low and then 3.6V p-p with a high.

hgmjr

#### beenthere

Joined Apr 20, 2004
15,819
A voltage comparator might do. Put a voltage above 2.7 on one terminal, and the output won't change until the higher 3.6 volt signal is present.

#### Mr.Dido

Joined Nov 18, 2007
5
Let me see if I understand your question.

You want to monitor a signal controlled by a switch. When the switch is OFF the signal you want to monitor is 2.7v p-p. When the switch is ON the same signal changes to 3.6v p-p.

Does the 2.7V p-p signal swing between 0V and 2.7V? If not, what two voltages does it swing between? The same information on the 3.6V p-p signal would be inportant to know. Also are both signals the same frequency?

It is unclear from you description whether you want to block the 2.7V p-p signal and pass the 3.6V p-p only or just generate a logic signal that indicates that the signal is 2.7V p-p with a low and then 3.6V p-p with a high.

hgmjr
Dear

the both signal swing between Vp-p to zero and frequency of them not equal as i remember and all what i want "block the 2.7V p-p signal and pass the 3.6V p-p only" by using DC voltage referance

regards

#### Mr.Dido

Joined Nov 18, 2007
5
About your simplest solution would be a 3v6 zener in series with the switch output.
Dear

thnx for ur information

regards

#### Mr.Dido

Joined Nov 18, 2007
5
A voltage comparator might do. Put a voltage above 2.7 on one terminal, and the output won't change until the higher 3.6 volt signal is present.
Dear

thnx for ur information

regards