I've looked around the site for suggestions, but think this question is a unique one and would love some conversation.
I need a method to measure the average power in to a transducer.
This method must
- Be able to measure the power of complex input waveforms (audio input, in this case)
- Be able to measure the power of a signal oscillating around a DC voltage
- Be able to measure the power of a signal oscillating around 0 V (AC)
- Be able to measure the power of a signal which oscillates around some DC value, and not fail when the oscillation is of such a magnitude that portions of the signal fall below 0 V
The general parameters of the waveforms I'm measuring are
- Audio, with and without DC bias
- Chirps, with and without DC bias
- Single frequencies, with and without DC bias
Before you ask, the DC bias is absolutely necessary! The physics of the devices for which I must determine the average power input require that I test signals with and without a bias.
In sum, I need a method of measurement which can accept voltage and current frequencies from 0-25kHz, is minimally invasive, is accurate to within a hundredth of a Watt (tenth might be okay too), and can handle voltages both with and without a DC bias that have peak to peak values from 0.1 V - 50 V.
An idea I've been given is that I could use transformers to remove the bias, measure the bias and the alternating component, and add them to obtain the average power.
Thanks in advance for any advice you can give!