Peak Detection

[Jeswin]

Hi,

I have a sensor that gives me a voltage drop when there is a change in the environment. And I have a positive peak detector that will detect the peaks of the highest voltage. Before the signal goes into the peak detector I am amplifying it.

I am faced with a challenge: My peak detector can only detect the highest value but I am interested in acquiring the final signal (after the voltage drop), which the peak detector cannot acquire. Could anyone suggest any method to solve this problem.

 

[Jaguarjoe]

What do you mean by "final signal after the voltage drop"? Where is the drop? Where is the final signal, before the peak detector, or before the amp?

 

[Jeswin]

Hi sorry about not being clear.

I want to retrieve the value of the signal when its at its minimum before the signal returns to its initial state. The peak detector only holds the highest value of the signal i.e. the original value of the signal (without any change in environment). The value before drop is 6.10Vpp and after drop it ranges between 4.5Vpp to 5.2Vpp.

 

[crutschow]

You could use a sample & hold. You need to provide a pulse to the S&H to acquire the signal. Do you know when the signal is at the value you are interested in?

 

[alec_t]

I want to retrieve the value of the signal when its at its minimum before the signal returns to its initial state.

Does that mean you want a negative peak detector as well as a positive peak detector?