what is the difference between ANALOG and DIGITAL quantities

hi
i want the answer of this question wich came to us in the exam of DIGITAL DESIGN
in the faculty og communication and control eng.


which of these quantities are analog and wich are digital:

1-number of hair of your head
2-setting time for microwave oven
3-radio volume control
4-atmospheric pressure
5-number of atoms in a sample material

regards

I think what that means is simply to differentialte between continuos and discrete quantities. Digital is discrete and Analog is continuous(though it can be sampled and then digitised). Based on the above assumption, i thought of the following answers...

1-number of hair of your head - Digital
2-setting time for microwave oven - Digital3-radio volume control - Analog
4-atmospheric pressure - Analog
5-number of atoms in a sample material - Digital

I've only made an attempt though. This is the first time i'm seeing such a question. Do tell us if you know the right solution.

Re: what is the difference between ANALOG and DIGITAL quanti

I´m agree with purifier post, but think that the questions are not right cos a timer could be setted by an analog way although that´s not common. The same for a radio volume control, as there are some that are digitally controlled.

There actually is no technical boundry between analog and digital. When you get right down to the quantum level everything is digital anyways, just once it passes a certain level of complexity it's considered analog. Digital electronics today can actually have finer degree's of graduation that some older analog components so even the number of possible steps is a poor judge of analog vs digital. Considering ADC's and DAC's the lines blurr even further considering super high quality ADC's and DAC's can convert from analog to digital process it and then convert it back to analog so well that there is virtually no difference. Basically though if you look at it under a microscope and you can keep zooming in till you reach the limit of your measuring device and still can't see the smallest change possible then it's analog. If you zoom in on your measurement and you can start to see the steps then it'd be digital.

Re: what is the difference between ANALOG and DIGITAL quanti

thx a lot for your replies

so quantities that can be "counted" is , in general , digital...

ok thx a lot

and i'd like to say that this was really a bad question since it may have different answers to some of its branches...

Re: what is the difference between ANALOG and DIGITAL quanti

just consider any continuous event as a analoge and the other as a digital
analogous is uccountable but measurable but digital are countable like rice and pen