ADC DAC With integrator output. V2.5

Wait about 2" to autostart or move your mobile to inject noise. A new NOT gate and latch make possible capturing data from a computer. V2.0 Now with integrated output in RED. +Vcc applied to output is for better view. To ease the understanding I build my own square generator and we can now see a complete sawtooth cicle. The upper left oscillator is to build a different Time Base for oscilloscope because it get reference only from Every Circuit oscillators. This is a real 4 bits ADC. As you know 4 bits gives us 16 sampled levels. The first counter (left) has two functions. - Building a sawtooth to use it as a signal comparator in sampling. - Giving us 16 binary values to store it later. The second counter is a latch to store binary value sampled. Obviously, bin-7seg and 8seg display show us the binary value sampled/stored. The operational is the comparator that trigger the latch when signal In(t) (orange) is lower than sawtooth signal (green). The next sample will be able when sawtooth complete its cicle (0-15 counts), then begin from 0. Nyquist theorem say that we need a sample frequency greater than twice the maximum frequency to be sampled. So because of this, we can see some different frequency. 10 Hz for "maximum audio signal to sample" 10 Hz x 4 =40 Hz sampled frequency f(s) not the counter clock. The counter clock is equal to f(s) x 16 levels. So Clock = 10 Hz x 4 x 16 levels/sampled = 640 clocks/second. (Now with my own generator) So square generator has no frequency control, only period time, we need to change frequency to period time. This is easy. .. The green 8-seg display show us the sawtooth sampled levels only as reference. As you can imagine, is easy to add more bits. Look at the resistors at the comparator. .. Hope you like it.

published 11 years ago