Gain controlled amplifier constant magnitude

[djnckln]

Hi all,

I would like to create a gain controlled amplifier to provide an output signal of constant magnitude.

I have an analogue input signal and want to amplify this signal to be of constant magnitude. I have searched for methods of how to do this but I am not making any progress. 

Please could anyone help with this?

Thanks in advance

[santo_13]

Seems to be an electronics application circuit design question - any reason you're posting on a LabVIEW board?

You will get better reach on other forums such as eevblog.

[djnckln]

Hi,

Thanks for the reply.

Yes, I want to use Labview to complete this task. I have an analogue input into Labview via a DAQ and I want to amplify the signal to a constant output.

Kind regards

[santo_13]

Please elaborate on your question. What model of DAQ, what kind of signal, LV version?

IMO, it is measure voltage using DAQ, apply scaling to reach the target amplitude, generate it back using AO. Note, there is a signal delay as it takes some time for the software to read the analog voltage, scale it and generate using analog output.

[djnckln]

Thanks again for the reply.

I am using a National Instruments NI USB-6341, the signal is a voltage input.

So yes, I measure voltage using the DAQ. I then want to amplify this signal and drive a voltage output with the amplified signal. I want to be able to limit the output signal to a constant. If the input signal increases the output signal will be too high for the DAQ if it is scaled, how do I limit the output?

Kind regards

[wiebe@CARYA]

You can pass (average) peak to peak amplitude to a PID controller.

:Post something. The solution depends a lot on the details.