High frequency sine wave voltage amplitude to 4-20mA?


This is a long shot, but I wonder if anybody can help me here. Is it possible to convert the amplitude of a sinusoidal burst signal into a stable 4-20mA response? If yes what device would allow so?

When controlling high frequency ultrasonic transducers (e.g. for NDT) the response is made of  multiple sinusoidal reflections.Would it be possible to convert the amplitude (or the RMS of the amplitude) of  high frequency (e.g. >1MHz, <10MHz) sinusoidal burst reflections into 4-20mA standard via an analog RF device? Further, would it be possible to do that in case of multiple reflections? Does the nature of this type of signals introduce any complication in such conversion?

Best Regards

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  • +1
    •  Analog Employees 
    on Mar 9, 2020 2:06 AM in reply to TheMasterKing001

    Hi ,

    If the amplitude rate of change is 1 Hz, AD5750 should be able to respond very well.

    You can start with sampling frequency as 10x the input frequency, more samples will give you better precision as you will be able to detect the "peak" of the input signal even with few periods of the input signal.

    If the input frequency and waveform is constant and defined, let's say a sine wave, you may opt for a lower sampling frequency then use the sampled data to get the approximate "peak" value of the input signal.

    You may use the usual data logger to measure the 4-20mA output from AD5750, or you may use a load resistor to convert it to voltage as long as it is within the output loop compliance voltage range.

    Output current is constant as long as VIN is constant.



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