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Quantization and LSB (MSB)
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Hey guys. If any of you know anything about this subject, please help me on /wsr/.

>>>/wsr/140412
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Also mods, please be kind this time. Pretty please
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>>55076982

if data is quantized it is not an irrational number when measured (like binary).

LSB and MSB just refers to positions within a register. The most significant bit is the digit with the most value. Remember binary is just base 2.

in base 10, if you have 9425, 9 is the most significant bit, 5 is the least significant bit.
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>>55077090
Ohh okay, thanks for explaining the LSB/MSB.

Could you please elaborate on the irrational numbers?
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>>55077090
For example lets say I have a signal like on the picture I posted. A sinusoid (or whatever it is called). How would I get an irrational number? For example if the signal goes on for five seconds and I measure it at 4 would I get something like fe 4.257845148918?
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LSB:
Least significant bit is related to representation of numbers using binary digits:

binary   decimal
000 0
001 1
010 2
011 3
100 4
101 5
110 6
111 7
1000 8


Now, if you flip one bit in a binary number, you get a different decimal number:
change 011 into 010 and 3 becomes 2
change 101 into 001 and 5 becomes 1
change 111 into 101 and 7 becomes 5

Depending on how close the binary digit you change to the right side, the decimal number can have greater or smaller change (3 into 2 is a change by 1; 5 into 1 is a change by 4).
There is one binary digit on the far right that when you flip it, the decimal number changes by one:
change 011 into 010 and 3 becomes 2
change 101 into 100 and 5 becomes 4
change 110 into 111 and 6 becomes 7

Because it has the least effect on the decimal number the binary sequence represents, it is called least significant bit.
Most significant bit is the one that causes the most change when you flip it, and it's on the far right side.
I'll elaborate on least significant BYTE in next post.

Quantization (not 100% sure on this one, but should be good enough for you since you have nothing):
If you have some signal, it's continuous in real world. Imagine signal lasts a second. At any point in this second the signal has a value, and there is an infinite amount of those points in a second. With quantization, you pick a limied set of points (out of an infinite amount of then) in time inside this one second interval, and for each one measure the value of signal.
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>>55077170

If you have something like boiling water and you stick a mercury thermometer in, the measurement is not technically quantized.

You could get a microscope and zoom n times and get a more specific measurement each time.

However, if you drew a thin black line with a nonzero width on the thermometer and labeled it "100 C", you could call everything under that black line 100 C. Now it's quantized.
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>>55077255
Least significant byte has meaning when you represent a number using a few bytes.
Say number N is represented by four bytes in memory, call then A, B, C and D.
Each of those bytes has an unsigned integer value, from 0 to 255 (or 2^8-1).
N is calculated using the formula:

N = A + 256*B + 256*256*C + 256*256*256*D


Changing any of A, B, C or D will change N.
Changing A by 1 will change N by 1.
Changing B by 1 will change N by 256.
Since A is the byte that has least effect on N, A is called most significant byte.
D is called most significant byte.

When writing bytes A, B, C, D to a file, or sending them over network, you send them in a particular order: usually either ABCD or DBCA.
When you send/write the least significant byte first, that is ABCD, it's called little endian format. When you sent most significant byte first, DBCA, it's called big endian.
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>>55077226

In the real world, you would get a finite number. Whatever tools you use would quantize the data.

In the mathematic world, you would get an infinitely specific number.
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>>55077255
Thank you very much man. This explanation of LSB is awesome and now I finally understand the chaotic notes my teacher provided. The Quantization is exactly what you said. In an 8bit scenario, there are 255 points. Depending on how many bits there are, we are supposed to calculate the "quantizated step" which is:
Qv = MR/(2^n)-1 with MR being in Volts so I assume it's some kind of Voltage.
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>>55077345
* Qv= MR/((2^n)-1)
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>>55077328
Oh so this is how they work. Oh man everything has been so chaotic the past year.
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>>55077336
Yup, thanks I know what's up now. It's putting a finite number of points into a mathematically infinite set of numbers.
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>>55077328
>A is called least significant byte.
Fixed. Fuck.
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Alright guys, thank you all very much for taking your time to explain what's up to me. We can let this thread die now :)
Thread replies: 15
Thread images: 1

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