Thread: digital and quantized signal, are one same thing?

1. digital and quantized signal, are one same thing?

2.

3. Originally Posted by scientist91
digital and quantized signal, are one same thing?
No. A quantized signal is a special kind of digital signal but a digital signal is not necessarily a quantized signal.

Digital signal as opposed to analog signal refers to how the information is stored in the transmission medium. And it means that rather than a continuous modulation of the amplitude or frequency, the information is transmitted by means of discrete changes. The simplest example would be a simple binary modulation between two different amplitudes.

The term "quantized signal" refers to a kind of digital simulation of the an analogue signal and can be used as an intermediate stage in the process of converting beween analog and digital signals.

4. Originally Posted by mitchellmckain
Originally Posted by scientist91
digital and quantized signal, are one same thing?
No. A quantized signal is a special kind of digital signal but a digital signal is not necessarily a quantized signal.

Digital signal as opposed to analog signal refers to how the information is stored in the transmission medium. And it means that rather than a continuous modulation of the amplitude or frequency, the information is transmitted by means of discrete changes. The simplest example would be a simple binary modulation between two different amplitudes.

The term "quantized signal" refers to a kind of digital simulation of the an analogue signal and can be used as an intermediate stage in the process of converting beween analog and digital signals.
And can "*" or "/" or "+" operations of calculator be transfered through digital signal?

5. ^^Yes, and nowadays all calculators do. The way in which digital signals can be used to compute such calculations is by using 'logic gates'. for example, two binary values (given by a string of digital states of 0 or 1), can be added together using whats called a 'full adder'....a circuit which is actually built from logic gates. binary values can be signed allowing for subtraction, and multiplication/ division can be carried out by looping the functions of additon and subtraction.

For example if you wanted 3*4, you can express this as the cumulative additon of 3 with itself the desired number of times, so it becomes:

3*4

is equivalent to:

3+3 loop 1
+3 loop 2
+3 loop 3
= 12

Nowadays an entire calculator is fitted onto a tiny microporcessor, which is atype of logic circuit (again built using logic gates), that can be programmed to perform function specific tasks.

6. Originally Posted by bit4bit
^^Yes, and nowadays all calculators do. The way in which digital signals can be used to compute such calculations is by using 'logic gates'. for example, two binary values (given by a string of digital states of 0 or 1), can be added together using whats called a 'full adder'....a circuit which is actually built from logic gates. binary values can be signed allowing for subtraction, and multiplication/ division can be carried out by looping the functions of additon and subtraction.

For example if you wanted 3*4, you can express this as the cumulative additon of 3 with itself the desired number of times, so it becomes:

3*4

is equivalent to:

3+3 loop 1
+3 loop 2
+3 loop 3
= 12

Nowadays an entire calculator is fitted onto a tiny microporcessor, which is atype of logic circuit (again built using logic gates), that can be programmed to perform function specific tasks.
The digital signal contain binary numbers (0, 1), right? How the digital signal is created? Is it created by implying voltage?

7. Yes a binary digit (bit) has two possible values...1 or 0...as opposed to a decimal number which can have 10 values, 0-9. These states can be called:

1 or 0
true or false
on or off
5V or 0V

I put voltage levels because these are typical voltage levels you have in logic circuits... In other words an on state, is when the voltage is 5V, and the off, when there is no voltage. So it's like discrete pulses of data rather than continous analogue. Examples of binary numbers are:

Decimal Binary
0 0
1 1
2 10
3 11
4 100
5 101
6 110
7 111
8 1000
9 1001

You should probably do some reading on this, casue theres plenty of good sources out there on the net....not to mention books.

8. Originally Posted by bit4bit
Yes a binary digit (bit) has two possible values...1 or 0...as opposed to a decimal number which can have 10 values, 0-9. These states can be called:

1 or 0
true or false
on or off
5V or 0V

I put voltage levels because these are typical voltage levels you have in logic circuits... In other words an on state, is when the voltage is 5V, and the off, when there is no voltage. So it's like discrete pulses of data rather than continous analogue. Examples of binary numbers are:

Decimal Binary
0 0
1 1
2 10
3 11
4 100
5 101
6 110
7 111
8 1000
9 1001

You should probably do some reading on this, casue theres plenty of good sources out there on the net....not to mention books.
Ok, I understand. So the digital signals are created with voltage, something like this?

9. Yeh exactly. (1) is when there is no voltage, 0 (This is not necessarily always 0V, but can even be at around 0.4V), and (2) is the on value, 1 (commonly 5V but not always...even when it is the voltage doesn't have to be exactly 5V)....thats the beauty of digital signals...it doesn't matter about interference, cos it will still be easily decoded.

The perfect digital waveform is a square/rectangular/pulse wave, with clean edges, but at (3) and (4) you sometimes get a voltage gradient as in the diagram due to the nature of some timing circuits...some are more accuarte than others, but in relatively low frequency circuits it doesn't make a huge difference anyway. High frequency circuits maybe.

10. Originally Posted by bit4bit
Yeh exactly. (1) is when there is no voltage, 0 (This is not necessarily always 0V, but can even be at around 0.4V), and (2) is the on value, 1 (commonly 5V but not always...even when it is the voltage doesn't have to be exactly 5V)....thats the beauty of digital signals...it doesn't matter about interference, cos it will still be easily decoded.

The perfect digital waveform is a square/rectangular/pulse wave, with clean edges, but at (3) and (4) you sometimes get a voltage gradient as in the diagram due to the nature of some timing circuits...some are more accuarte than others, but in relatively low frequency circuits it doesn't make a huge difference anyway. High frequency circuits maybe.
And how the digital signal is decoded, so we see the result on the calculator?

11. bit4bit, do u know?

12. A data 'bus' feeds an outputted digital signal to an LCD display from the microcontroller, which shows the particular symbols on the display of whatever number or operation you are using.

The entire system is:

keypad > microcontroller > LCD display

in general, most automated electrical systems have the form:

Input device(s) > microcontroller > Output devices(s)

You may also need some intermediate circuitry between input/output devices depending on what they are, and what your microcontoller is. Microcontrollers are complete computing units that contain a microprocessor/registers/PROM(for program memory)/input/output ports/ and some extra periphials like ADC's (Analogue to digital converters).

13. Originally Posted by bit4bit
A data 'bus' feeds an outputted digital signal to an LCD display from the microcontroller, which shows the particular symbols on the display of whatever number or operation you are using.

The entire system is:

keypad > microcontroller > LCD display

in general, most automated electrical systems have the form:

Input device(s) > microcontroller > Output devices(s)

You may also need some intermediate circuitry between input/output devices depending on what they are, and what your microcontoller is. Microcontrollers are complete computing units that contain a microprocessor/registers/PROM(for program memory)/input/output ports/ and some extra periphials like ADC's (Analogue to digital converters).
Are there any transistors. I read somewhere that the flip-flops are made of transistors. What are the logic gates made of?

14. Flip-flops are 'sequential logic' circuits which depend on both the present state AND the previous state of the inputs as opposed to simpler 'combinational logic' circuits (which depend only on the present input states) from which they're made.

Sequential logic circuits are built from combinational logic circuits, and combinational logic circuits are build from transistors (and resistors). This is all encapsulated by the microcntroller on it's integrated circuit that contains 100,000's of transistors, making up the combinational and sequential logic circuits that are used to perform the tasks that it was programmed to do.

There wouldn't be any need to use transistors externally in the calculator system above. (And this is the most common set-up of a calculator)

15. Originally Posted by bit4bit
Flip-flops are 'sequential logic' circuits which depend on both the present state AND the previous state of the inputs as opposed to simpler 'combinational logic' circuits (which depend only on the present input states) from which they're made.

Sequential logic circuits are built from combinational logic circuits, and combinational logic circuits are build from transistors (and resistors). This is all encapsulated by the microcntroller on it's integrated circuit that contains 100,000's of transistors, making up the combinational and sequential logic circuits that are used to perform the tasks that it was programmed to do.

There wouldn't be any need to use transistors externally in the calculator system above. (And this is the most common set-up of a calculator)
But how the calculator memorizes some operations? (Lets say if I press the number 3 and after a while "+" and after 30 sec. the number 5), how the calculator memorizes the operation "+"?

16. When you press a key, an electrical (logic) pulse is sent to an input on the microcontroller, where the corresponding binary value is stored in an internal 'register'. (These are small memory circuits built using sequencial logic circuits such at the SR NAND bistable...or flip-flop as it's called....electronic memory relies on sequential logic circuits to 'latch' states)

Then when you press the addition key, a pulse is sent to the microcontroller, which recognises it as addition, and prepares the ALU (arithmetic logic unit) to process an addition. The next number is then stored, and upon pressing the 'equals' key, the ALU retrieves the two values from memory, and performs addition on them.

For more in depth explanation of how it works you really need to look closer at combinational, and sequential logic circuits....these are the basic building blocks for all digital circuits.

17. What is the role of the transistors in microchip? Do that pulse is continuous, or it is just released?

18. Transistors make up the logic circuits, that perform the operations.... :wink:

The input is pulsed and latched in a memory register within the chip, ready to be used. next time it's pressed it will do the same again.

19. Originally Posted by bit4bit
Transistors make up the logic circuits, that perform the operations.... :wink:

The input is pulsed and latched in a memory register within the chip, ready to be used. next time it's pressed it will do the same again.
And do you know how it stores them?

20. bit4bit?

where the corresponding binary value is stored in an internal 'register'. (These are small memory circuits built using sequencial logic circuits such at the SR NAND bistable...or flip-flop as it's called....electronic memory relies on sequential logic circuits to 'latch' states)
http://en.wikipedia.org/wiki/Sequential_logic

http://en.wikipedia.org/wiki/Flip-fl...electronics%29

22. Originally Posted by bit4bit

where the corresponding binary value is stored in an internal 'register'. (These are small memory circuits built using sequencial logic circuits such at the SR NAND bistable...or flip-flop as it's called....electronic memory relies on sequential logic circuits to 'latch' states)
http://en.wikipedia.org/wiki/Sequential_logic

http://en.wikipedia.org/wiki/Flip-fl...electronics%29
And how those transistors, can calculate numbers and memorize numbers?

23. If you had bothered to listen to what I've said over the course of this thread, and to do some reading of your own...especially when relevant material is provided, you would know that yourself by now, and would not have to take my word for it. It'd be nice if you said thanks once in a while too.

24. Originally Posted by bit4bit
If you had bothered to listen to what I've said over the course of this thread, and to do some reading of your own...especially when relevant material is provided, you would know that yourself by now, and would not have to take my word for it. It'd be nice if you said thanks once in a while too.
Thank you very much for everything. I appreciated your efforts to help me. Just I can't find that information. I read all about it. Sorry, If I am annoying.

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