ADC sigma-delta

328

05:24:23

1)open the capacitor switch.
2)close the input switch.
3)Use a simple RC low pass filter to convert the digital signal back to analog.

published 6 years ago

fatcat2

6 years ago

How did you select the RC time constant of the integrator?

bryanthehacker

6 years ago

The RC constant must be bigger than clock period but much lower the signal period.

fatcat2

6 years ago

Thank you!

bryanthehacker

6 years ago

In this case, the integrator is not good, you need very high clock frequency for this ADC. For example, for audio applications you need 1-2 MHz clock. If tuned correctly, this ADC can go over 24bit resolution. HiFi audio systems often use sigma-delta ADC.

fatcat2

6 years ago

What about the output filter?

bryanthehacker

6 years ago

To convert the bit flow back to analog signal, use a simple low pass filter. For example, you can send the bit flow with fiber optic to a far receiver, after the optical frontend just put a RC filter and send the analog signal to an audio amplifier.

fatcat2

6 years ago

I find that the distortion is too high with a simple RC filter.

bryanthehacker

6 years ago

Because the clock frequency is too low and the integrator isn't properly tuned.

fatcat2

6 years ago

Thank you.

add comment in editor

EveryCircuit is an easy to use, highly interactive circuit simulator and schematic capture tool. Real-time circuit simulation, interactivity, and dynamic visualization make it a must have application for professionals and academia. EveryCircuit user community has collaboratively created the largest searchable library of circuit designs. EveryCircuit app runs online in popular browsers and on mobile phones and tablets, enabling you to capture design ideas and learn electronics on the go.