Do I understand how this Digital Integrator circuit is supposed to work?

Question

So I need to build a circuit that operates according to this block diagram and explanation: http://puu.sh/rTqfu/0e56b48637.png

This is how I think the circuit should work:

1. Put an input signal into an ADC, check the MSB to see whether the input is positive or negative, and count up if it is positive, and down if it is negative.

2. The 8-bit count gets added into a register, with whatever is in the register.

3. The register is outputted into an 8-bit DAC, and the output should be the integral of the input.

Am I anywhere close on this? I'm not sure I fully understand how the circuit should work. I made a design for the circuit in multisim, but my output doesn't look quite right.

Here is the circuit I designed: http://puu.sh/rTr2k/3535af3290.png

And output: whttp://puu.sh/rTr43/723355f566.jpg

My circuit uses an adder to determine wether the input is + or -, and that gets fed into my cascaded 8-bit Up/Down counters. That count gets inputted into a cascaded 8-bit adder, and the feedback from the 8bit register is added with the count. The output is fed into a DAC and shown on an ocsilloscope.

If you could explain to me how this is supposed to work practically, if I'm WAY off, that would be amazing.

Answer 1

I must confess.

I did not check your circuit in detail, but I think you understand the concept OK.

A counter is a Digital integrator because it accumulates the events per unit time, if operating at a fixed frequency.

We can enable and disable integration by the clock control and we can vary the gain of the integral by changing the speed of the clock or simply just count events.

We could also change the gain, as in this case, using a parallel adder and accumulator to integrate or count the total number of events over time.

Then you can get fancy and use an ADC to create the values to control gain of the integrator or accumulate the events per unit time or some period of time.

You can integrate in a spreadsheet too or just with an Op Amp and capacitor feedback and resistor compared to a Voltage reference or use a microwave integrator.

There are many ways to perform this "integration of an input over time" , each critically depending on the specifications and tolerances needed.