AT 89S52

Analog Devices AD736

Thank you for your help.As you suggest IC AD736 ,we are working on it.If any trouble will come across i will tell you.

Thank you once again.

i want to add one more query to my previous one.that is "am using AT 89S52 microcontroller and i want to measure average value of a signal with frequency between 10khz-15khz with voltage range upto 5V. is there any IC available which will directly give me an average value ? if there is any other solution please let me know."

Thank you

You still haven't answered the question: Do you mean RMS?

If not, what do you mean by "average"?

Yes i mean to say RMS.

The datasheet of the AD736 gives the input/output range. It should be no problem to add an opamp and/or voltage divider (with trimm potentiometer) to fit your requirements.
Besides - this is not KEIL stuff.

Is that the true RMS value of any arbitrary signal, or is it sufficient to just assume a sine wave?

no its not a sine wave, i want to measure it for rectangular and square wave which have amplitude of 5v.

It is important to know if you need to measure the bandwidth up to 10khz-15khz, or if 15kHz is the fastest frequency of the signal.

If you have a 15kHz signal you may need a lot more bandwidth, depending on the signal shape.

Anyway, RMS becomes trivial for squarewave...

for RMS at 15kHz you need a fast ADC and a fast micro. Just do a rough estimate of how many samples you need in ~66ms

Erik

Well, how lovely if 66ms was enough :)

that, of course is 66us

Erik

If your signal is either 5V or 0V (rectangular or in special square wave) it should be sufficient do sample this two states and calculate the on/off ratio.

"If your signal is either 5V or 0V (rectangular or in special square wave)..."

Just to be clear that I'm uderstanding you here:

Are you saying that, if you can assume that the signal is a perfect square wave, and that the two states can only ever be precisely 5.00V and precisely 0.00V, then there is no point in having an Analogue-to-Digital converter?

Yes?