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  4. Is it possible to convey an information by "on" and "off" state?
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Is it possible to convey an information by "on" and "off" state?

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Offline Mitko Gorgiev (OP)

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Is it possible to convey an information by "on" and "off" state?
« on: 10/11/2020 18:36:00 »
In the topic started by me:
What are digital logic circuits?
https://www.thenakedscientists.com/forum/index.php?topic=78466


I show that it is an enormous misconception of today’s electrical engineering when it says that “zero” represents no current/voltage and “one” represents current/voltage.

In a conversation with a friend of mine, I was asserting that it is impossible to convey an information with these two states: “no signal” and “signal”. That is, I was asserting that both states must be signals - different signals, of course.

To oppose my assertion, he offered the example of a number of lamps going on and off:


These 8 rows of circles are different states of only three lamps which turn on and off, and each new row at the figure is a new state of the lamps at equal intervals. It is actually a 3-bit counter.

Here we have a case where seemingly an information is conveyed by two states: on and off. But there is a flaw in this way of thinking. Why?
Because both states are signals, that is, when a lamp is off, it is also a signal. We do see that a lamp is off.
To make it clearer, imagine that the lamps go on and off in total darkness. Look at the image below:


Only two lamps of a larger number of them are on. But this time we can’t see how many lamps are off between the two which are on. Because of this, we cannot tell which binary number represents this state of the lamps.
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Offline Bored chemist

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Re: Is it possible to convey an information by "on" and "off" state?
« Reply #1 on: 10/11/2020 19:21:13 »
Quote from: Mitko Gorgiev on 10/11/2020 18:36:00
I show that ...
No you didn't.

Quote from: Mitko Gorgiev on 10/11/2020 18:36:00
I show that it is an enormous misconception of today’s electrical engineering when it says that “zero” represents no current/voltage and “one” represents current/voltage.
It doesn't say that.
Not since the days of "fat zero and skinny zero" transmissions, and 4-20 mA loops.
Congratulations on discovering something that has been known for 70 years.

Did you consider studying the subject before commenting on it?

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Offline Halc

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Re: Is it possible to convey an information by "on" and "off" state?
« Reply #2 on: 10/11/2020 20:02:46 »
A zero voltage on a line is a voltage, quite distinct from the lack of a voltage just like zero is quite distinct from not-a-number.  So a '0' signal (whatever arbitrary voltage one decides to assign to that value), being distinct from the different voltage assigned to '1', conveys information.  I assure you (being in the industry) that there is no standard that the '0' signal need be lower voltage than the '1' signal.  Very often the signals are not distinct voltages at all, but perhaps a spin, charge, or frequency difference.
A difference in voltage is not necessarily a difference in current. Either can change without a change in the other.

As for the lamps in total darkness, there is still information there in the absence of a grid of lines where each signal is located.  Look at a standard UPC bar code, which essentially is signal (black/ink) and no signal (blank page) alternating with no grid.  The widths of the lines are not what matters since a bar code can be scaled up or down without affecting its ability to be scanned.  The information in the UPC is nevertheless conveyed.

It is hard to tell from your post what you are proposing.  What is your hypothesis or question? Clearly the answer to the question in the title is yes, as evidenced by the computer you used to post the topic despite the 'enormous misconception of today’s electrical engineers' that designed it.
« Last Edit: 10/11/2020 20:05:59 by Halc »
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Offline evan_au

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Re: Is it possible to convey an information by "on" and "off" state?
« Reply #3 on: 10/11/2020 20:09:57 »
Quote from: OP
Because both states are signals, that is, when a lamp is off, it is also a signal.
The technical term is "symbol": Both 0 and 1 are symbols.
- A sequence of digital symbols constitute a digital signal.
- And a sequence of symbols can convey information.
- In the case of a lamp being ON or OFF (or a voltage being HIGH or LOW), each symbol conveys 1 bit of information.
- In the case of the fairly common VDSL2 signal, each symbol can convey around 25,000 bits of information.

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we can’t see how many lamps are off between the two which are on.
This is because you have obscured the OFF symbols. Obscured symbols convey less information (potentially no information).

The other thing you are missing is that when you present a sequence of symbols, the timing of those symbols becomes critical. If you measure the signal while it is changing, you are likely to get confused and read the wrong symbol.

Thus "clocking" or "synchronization" is very important in digital communications: This allows you to measure the signal at the optimum time to extract the symbols with minimum error.
- In the old "ticker-tape" machines, information was printed on paper tape as a sequence of holes. Across the paper tape there were 8 rows of big holes for information, and a row of small holes providing the clocking information, so that the big holes could be read at the optimum time.
- These days, a computer bus may have 64 wires carrying data signals, plus an extra wire carrying a clock signal
- For long-distance communications, it is usual to mix the clock in with the signal, so that periodic transitions in the signal can be used to derive the clock signal, which is used to detect the symbols at the optimum time.
- Clocking is also used in the UPC code mentioned by Halc.
- Including the clock signal with the data symbols slightly reduces the capacity of the communications link, but there are increasingly sophisticated ways of carrying a clock signal without wasting too much bandwidth. These typically require a better quality local clock at transmitter and receiver, which can remain synchronized with each other for longer periods before being corrected.
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Offline Mitko Gorgiev (OP)

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Re: Is it possible to convey an information by "on" and "off" state?
« Reply #4 on: 11/11/2020 22:25:40 »
Quote from: Halc on 10/11/2020 20:02:46
It is hard to tell from your post what you are proposing.  What is your hypothesis or question? Clearly the answer to the question in the title is yes, as evidenced by the computer you used to post the topic despite the 'enormous misconception of today’s electrical engineers' that designed it.
If you have read the linked topic in the beginning of my OP, you should have understood what its purpose is.
Look please at the figure below:

* sine curve.png (6.04 kB . 618x263 - viewed 3055 times)
What do you see? A sine curve. What does it represent? An alternating current flowing one half cycle in one direction, the next half cycle in the opposite direction.
Those Plus and Minus, somebody additionally called “one" and “zero”.

* sine curve_0_1.png (6.44 kB . 618x262 - viewed 3131 times)
What do you see below? A square wave. A so-called clock. This clock is composed of “ones” and “zeros” alternately.

* Clock.png (4.46 kB . 620x280 - viewed 3168 times)
Do you think that there is an essential difference between the second and the third picture? No, there is not. “One” and “zero” in the digital electronic circuits are completely identical in intensity, only different in sign.

Here is quotation from Wikipedia, which in this or similar form can be found in millions of textbooks.
"In most digital circuits, the signal can have two possible valid values; this is called a binary signal or logic signal. They are represented by two voltage bands: one near a reference value (typically termed as ground or zero volts), and the other a value near the supply voltage."

This is the hugest misconception of the digital electronics: it speaks of two different voltage bands in intensity. One is high voltage, the other is "Ground" or "zero volts".

NO, NO and NO again.
Both have the same intensity.

I can get shocked from a voltage, but I can’t get shocked from “ground” or zero volts.

Read the first part of my linked topic to see what I am talking about.
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Offline Bored chemist

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Re: Is it possible to convey an information by "on" and "off" state?
« Reply #5 on: 11/11/2020 22:28:30 »
Quote from: Mitko Gorgiev on 11/11/2020 22:25:40
Read the first part of my linked topic to see what I am talking about.
You are clearly wrong here.
Why would I go to your other topic?
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Offline Halc

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Re: Is it possible to convey an information by "on" and "off" state?
« Reply #6 on: 11/11/2020 23:46:21 »
Quote from: Mitko Gorgiev on 11/11/2020 22:25:40
What do you see below? A square wave. A so-called clock. This clock is composed of “ones” and “zeros” alternately.

* Clock.png (4.46 kB . 620x280 - viewed 3168 times)
...
“One” and “zero” in the digital electronic circuits are completely identical in intensity, only different in sign.
Sign is arbitrary, and there only because you put a reference value (the black line) in the middle of the picture.  Usually the reference value is below both both voltages, making the difference between the two not one of sign, simply one of lower voltage, and higher voltage.  Current rarely plays much of a roll since most of the current occurs during switching of states, and not much (if any) during the holding of it.

Quote
Here is quotation from Wikipedia, which in this or similar form can be found in millions of textbooks.
"In most digital circuits, the signal can have two possible valid values; this is called a binary signal or logic signal. They are represented by two voltage bands: one near a reference value (typically termed as ground or zero volts), and the other a value near the supply voltage."

This is the hugest misconception of the digital electronics: it speaks of two different voltage bands in intensity. One is high voltage, the other is "Ground" or "zero volts".

NO, NO and NO again.
Both have the same intensity.
The quote you gave made no mention of 'intensity'. Not even sure what intensity is, since it doesn't seem to be a physics term related to electricity.  A light can have intensity, and the only mention of intensity on the wiki site refers to varying intensity of light (used for centuries), not electrical voltage or current.
What exactly do you claim is wrong with what the site you quote says?  All that matters is that the two values can be distinguished, which they can.

Quote
I can get shocked from a voltage, but I can’t get shocked from “ground” or zero volts.
Nonsense. I've been shocked innumerable times from touching something grounded.  All that's required is a difference in voltage, not which voltage you've arbitrarily decided to assign as 'ground'.

Quote
Read the first part of my linked topic to see what I am talking about.
Post your argument here, or continue the discussion in the other topic.  I shouldn't need to click a link to follow whatever you're pushing in this topic.
Besides, the linked topic doesn't seem to have a specific stated thing for which it is arguing.
I've done digital logic circuits all my life, with my specialty being asynchronous state machines (no clock).
« Last Edit: 11/11/2020 23:55:14 by Halc »
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Offline hamdani yusuf

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Re: Is it possible to convey an information by "on" and "off" state?
« Reply #7 on: 16/11/2020 07:53:48 »
In practice, logic circuits need to consider noise and uncertainty.
https://en.wikipedia.org/wiki/Transistor%E2%80%93transistor_logic#Interfacing_considerations
Quote
Standard TTL circuits operate with a 5-volt power supply. A TTL input signal is defined as "low" when between 0 V and 0.8 V with respect to the ground terminal, and "high" when between 2 V and VCC (5 V),[21][22] and if a voltage signal ranging between 0.8 V and 2.0 V is sent into the input of a TTL gate, there is no certain response from the gate and therefore it is considered "uncertain" (precise logic levels vary slightly between sub-types and by temperature). TTL outputs are typically restricted to narrower limits of between 0.0 V and 0.4 V for a "low" and between 2.4 V and VCC for a "high", providing at least 0.4 V of noise immunity. Standardization of the TTL levels is so ubiquitous that complex circuit boards often contain TTL chips made by many different manufacturers selected for availability and cost, compatibility being assured. Two circuit board units off the same assembly line on different successive days or weeks might have a different mix of brands of chips in the same positions on the board; repair is possible with chips manufactured years later than original components. Within usefully broad limits, logic gates can be treated as ideal Boolean devices without concern for electrical limitations. The 0.4V noise margins are adequate because of the low output impedance of the driver stage, that is, a large amount of noise power superimposed on the output is needed to drive an input into an undefined region.

https://en.wikipedia.org/wiki/Three-valued_logic
Quote
In logic, a three-valued logic (also trinary logic, trivalent, ternary, or trilean,[1] sometimes abbreviated 3VL) is any of several many-valued logic systems in which there are three truth values indicating true, false and some indeterminate third value. This is contrasted with the more commonly known bivalent logics (such as classical sentential or Boolean logic) which provide only for true and false.

https://en.wikipedia.org/wiki/Four-valued_logic
Quote
Nuel Belnap considered the challenge of question answering by computer in 1975. Noting human fallibility, he was concerned with the case where two contradictory facts were loaded into memory, and then a query was made. "We all know about the fecundity of contradictions in two-valued logic: contradictions are never isolated, infecting as they do the whole system."[1] Belnap proposed a four-valued logic as a means of containing contradiction.[2][3]

He called the table of values A4: Its possible values are true, false, both (true and false), and neither (true nor false). Belnap's logic is designed to cope with multiple information sources such that if only true is found then true is assigned, if only false is found then false is assigned, if some sources say true and others say false then both is assigned, and if no information is given by any information source then neither is assigned. These four values correspond to the elements of the power set based on {T, F}.

T is the supremum and F the infimum in the logical lattice where None and Both are in the wings. Belnap has this interpretation: "The worst thing is to be told something is false simpliciter. You are better off (it is one of your hopes) in either being told nothing about it, or being told both that it is true and also that it is false; while of course best of all is to be told that it is true." Belnap notes that "paradoxes of implication" (A&~A)→B and A→(B∨~B) are avoided in his 4-valued system.
Quote
A four-valued logic was established by IEEE with the standard IEEE 1364: It models signal values in digital circuits. The four values are 1, 0, Z and X. 1 and 0 stand for boolean true and false, Z stands for high impedance or open circuit and X stands for don't care (e.g., the value has no effect). This logic is itself a subset of the 9-valued logic standard called IEEE 1164 and implemented in Very High Speed Integrated Circuit Hardware Description Language, VHDL's std_logic.
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Offline Bored chemist

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Re: Is it possible to convey an information by "on" and "off" state?
« Reply #8 on: 16/11/2020 11:37:09 »
"Is it possible to convey an information by "on" and "off" state?"
Is your computer working?
If so, you have direct proof that the answer to the question is "yes".
This thread logicaly has nothing left to say.
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