A simulation was run to mimic the future role of our software. Having implemented DC detection we can now determine the DC bias from the ADC. In the future this software must be able to detect the DC bias and attempt to remove it by writing dynamic software to control the DACs. In addition the software must be able to detect the peak-to-peak signal amplitude and reason how to provide gain. Gain is provided by using a Programmable Gain Amplifier (PGA) to provide gain in steps.
The first simulation ran demonstrated what the PGA will do. A sine function with a random AC amplitude (0 to 100mV) was generated. I then built a stage capable of detecting the peak-to-peak AC amplitude. I then used a for loop to run through each PGA options (1, 2, 5, 10, 20, etc.) to check if the signal was above 5 volt. If the signal was less than 5 volt then it is selected as the true PGA. In the figure below you will see operation of several different simulations. As you can see, with different random AC amplitude the gain is dynamically modified.maximum dynamic range of the signal would be 5 v.
The simulation below show the response of the simulation to different initial signal AC amplitudes. As can be seen, a smaller AC amplitude will allow a higher gain value.
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