Bit Definition and 398 Threads

The bit is the most basic unit of information in computing and digital communications. The name is a contraction of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represented as either "1"or"0", but other representations such as true/false, yes/no, +/−, or on/off are commonly used.
The correspondence between these values and the physical states of the underlying storage or device is a matter of convention, and different assignments may be used even within the same device or program. It may be physically implemented with a two-state device.
The symbol for the binary digit is either "bit" per recommendation by the IEC 80000-13:2008 standard, or the lowercase character "b", as recommended by the IEEE 1541-2002 standard.
A contiguous group of binary digits is commonly called a bit string, a bit vector, or a single-dimensional (or multi-dimensional) bit array.
A group of eight binary digits is called one byte, but historically the size of the byte is not strictly defined. Frequently, half, full, double and quadruple words consist of a number of bytes which is a low power of two.
In information theory, one bit is the information entropy of a binary random variable that is 0 or 1 with equal probability, or the information that is gained when the value of such a variable becomes known. As a unit of information, the bit is also known as a shannon, named after Claude E. Shannon.

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  1. B

    Feeling a bit lost with an MPhys degree

    I'm in the penultimate year of my MPhys degree and I am on track to get a 2.1 I am good friends with the people in the year above me and speaking to them has made me feel a little lost re: careers. Medical physics is something that really interests me, and something I was planning on...
  2. R

    Isn't M-theory and the multiverse idea a bit discouraging?

    I have been reading about the multiverse idea recently and when I came to think of it , as much as I find it extremely interesting, isn't it a bit discouraging as well? I mean, if there was "time" before the big bang and if there are infinite number of other "bubble" universes in the "11th...
  3. K

    Calculating Energy Per Bit from Symbols Constellation

    In general, if I have a constellation of symbols, how can i calculate the energy por bit? I think I should calculate the area of figure which is formed linking external points in the space signal and divide it for the numer of bit compose the symbols. Right?
  4. K

    MATLAB Bit of help with piecewise and parametric functions in MATLAB?

    Hi guys, after using the forum for ages for help I decided to make an account, so hopefully I might be able to contribute something as well, who knows :) I'm a first timer with MATLAB and have been set an assignment. I'm completely stuck on question one: The following image shows my code and...
  5. S

    Mathematica I need a little bit help about mathematica

    Hello, my problem is that I could not be able to find to separate the roots with the command of FindRoot. Altough I have 2 non-linear equations, I can solve these with FindRooot, but I'd like to have separetely the roots I mean independent roots each other (x apart and y apart). I wonder if i...
  6. H

    Exploring 8-bit BCD and Integers: How Many Can be Represented?

    Homework Statement Suppose a computer has 8-bit words. How many different integers can be represented (in decimal) in a single word if the integers are represented in binary coded decimal(BCD)? Homework Equations BCD= Binary Coded DecimalThe Attempt at a Solution BCD is coded in 4 bits so...
  7. R

    Game Theory a problem which is a bit similar to the Impossible Puzzle

    Game Theory a problem which is a bit similar to the "Impossible Puzzle" From numbers 1 to 10, two integers X, and Y (not necessarily distinct) are chosen by a referee . The referee informs secretly to Joe the integer U where U = X + Y . The referee informs secretly to Bob the integer V where V...
  8. J

    I've gotten stuck with a bit of dirac notation calculation?

    sorry if this looks ugly but I couldn't find out how to write out bras and kets on the Latex thing. I have these inner products <f|g> = i<x|(AB - A<B> - <A>B + <A><B>)|x> and <g|f> = -i<x|(BA - B<A> - <B>A + <A><B>)|x> where |x> is some arbitrary ket and A and B do not commute. I'm trying to...
  9. P

    A bit OffTopic: ideas for astronomy/astrophysics gift pack

    Hello! This is my first post here, I hope to have hit the right sub-forum. Recently a good friend told me that she is fascinated by astronomy and astrophysics. I'd like to put together a pack of material for her as a gift. Since I don't know much about the topic myself (although I love...
  10. J

    A straightforward matrix eigenvectors/values problem, I'm a bit rusty?

    here's the problem: "In a two dimensional vector space, consider the operator whose matrix is written as \sigma_x = \left(\begin{array}{cc}0&1\\1&0\end{array}\right) . in an orthonormal basis {|1>, |2>}. Calculate the eigenvalues and normalised eigenvectors for the operator in this basis."...
  11. D

    Internship stretched a bit from my field

    I am a Math and Physics major. I eventually hope to go to graduate school for one or the other. The areas of Physics I am more interested in are a bit more towards academic research, not really applied physics or engineering. I have a friend who has a farther that works for an applied physics...
  12. E

    Conservation of mechanical energy and external forces. A bit confused

    Hi I got a question regarding conservation of mechanical energy. The mechanical energy of a system is conserved, as long as there are no transfer of energy (like heat, work, mechanical waves etc.), right? So, why is the mechanical energy in the system of the pivoting rod and the earth, as...
  13. J

    Do you think Newton is a bit overrated?

    I admire Newton's work and agree that he was a great scientist. He came up with many new original ideas. But there are many other scientists who are equally or perhaps more great who are not held as high as Newton. Some of the names which I could think of off hand are: Archimedes, Leibniz. My...
  14. S

    A jumble of basic SUSY questions (i.e. a bit confused and seeking help)

    So, I've been tasked to learn SUSY in a small time span (few weeks) and I've made some progress but I'm a little stumped on how deeply I should go into things while still making reasonable progress (get to phenomenology, etc). First of all, most primers seem to gloss over the algebra or go...
  15. Nick666

    Clarifying Mathematical Confusion: The Truth About 1010101010

    My math is rusty so please tell me 1010101010 does not equal (((1010)10)10)10 , right ?
  16. M

    Need a Tiny Bit of Help with 555 Oscillator Frequency Formula

    With regards to this http://www.electronics-tutorials.ws/waveforms/555_oscillator.html, I figured out how to get t2 fine, but I have a problem figuring out how to get t1...I know when the negative-going waveform at pin 2 crosses Vcc/3, pin 3 goes to Vcc, and pin 7 gets internally disconnected...
  17. S

    2 Bit Adder: Inputs 0,1,0,1 Outputs

    Hello! I've been working out the truth table to a logic gate which I've been told is a 2 Bit Adder. The inputs, in the order of the truth table below are 0, 1, 0, 1. Inputs: Outputs: 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 1 0 0 0 0 1 0 0 1 0 0 1 0 0 0 0 1 0 0 1 1 1 0 0 0 1 1 1...
  18. B

    A bit lost in the science/engineering fields

    When I first started high school, I was pretty dead set on being an engineer. Now, it's college apps time, and I'm more clueless than when I started. Why? Over the years I've become more and more tired of math. Geometry was fun - but starting from Algebra I've felt like a human calculator, to...
  19. V

    Creating a Bit Detector with Mealy Machine: State Diagrams & Tables

    Homework Statement I have to make a scheme of a bit detector that detects the bit "1101" with a Mealy Machine. So I have made the following state diagram and state table(picture 1 and picture 2) http://img215.imageshack.us/g/picture1jf.png/" Now I don't know what happens in picture 3. How...
  20. P

    What is the angular velocity of the drill bit in radians per second?

    Homework Statement This problem is for a cordless drill. http://img718.imageshack.us/img718/8531/drill1.jpg Homework Equations [PLAIN][PLAIN]http://img442.imageshack.us/img442/3511/drill2.jpg where N denotes number of teeth w denotes angular velocity The Attempt at a...
  21. C

    How can I solve a problem with two equations in two unknowns using trigonometry?

    Hi, I have a problem that arose in one of my courses that I've gotten stuck on. I reduced it to two equations in two unknowns but can't get any further. I've apparently forgotten all the trigonometry I used to know. C = Acos(x) + Bcos(y) 0 = Asin(x) + Bsin(y) where A,B,C are known but...
  22. M

    Paradox: Who Will Be the Oldest After Travelling Near Light Speed?

    Here comes the model situation. I have a man on a planet and two ships. One ship will go straight to from a planet and another one will go opposite direction. Well that's for me very interesting. Because i will travel with ship near to speed of light from Earth the Earth time will be for me...
  23. M

    Simple Integral. I'm a bit rusty.

    Homework Statement Take the integral of 1/[(z^2 + x^2) ^ 3/2] dx where z is a constant. Homework Equations The Attempt at a Solution I tried substitution, but couldn't get it to work. Thanks in advance.
  24. Saladsamurai

    Fortran Which FORTRAN Compilers are Compatible with Windows 7 32-bit?

    Hello all, Although I am currently working on implementing FORTRAN on my Mac, I would also like to find a compiler that works well with Windows 7 32-bit. I initially had Win7 64-bit installed on my computer, but when I went to use my (really old) DIGITAL Visual Fortran install disk, it said it...
  25. A

    News Can Expanding Access to Medicare Really Solve the US Healthcare Crisis?

    I am not into politics, but one issue that has bugged me is the missed opportunity of the last 2 years. There are very few moments in US history when one party holds the super majority, that precious balance that is veto proof. I was really looking forward to an overhaul of the US...
  26. Z

    Why can't we use quantum bit entanglement for FTL information?

    I don't understand. Why can't we use quantum entanglement by the means of altering a state of an entangled electron so we can send an instantaneous bit of information to anywhere in the universe infinitely fast by the other electron changing its quantum state? We can can in theory transmit...
  27. M

    Centroids please need a bit of help

    I'm not sure wether the top shape triangle the x-axis should be minus or plus. i've got all the areas including x1 x2 x3 x4 and y1 y2 y3 y4 since I've splited the whole shape into 4 shapes (2 triangle and 1 square and 1 rectangle).would appreaciate if anyone can help me out with it...
  28. M

    Using 4x4 bit multipiers to do an 8x8 bit multiply

    Hi How would I use 4x4bit multipliers to calculate an 8x8 bit multiply? Thanks
  29. A

    A bit of a confusion regarding light, speed of it

    I have a doubt regarding the speed of light. What makes it impossible to achieve it. Why can't we have a relative velocity greater than that of C. Some say you should not apply common physical world logic in these fields. But, Consider we have 2 laser sources separated by 2c distances. Say we...
  30. S

    Center of mass and a bit vector calculus

    Hi guys, recently I am reading Kleppner's Mechanics about center of mass, well, I am always a fairly fast learner, but I really got stick here. you see, in the page 119 example 3.3 (in short, a rod with nonuniform density ) let Q(x) be the function density of location vector it said...
  31. T

    Are Electromagnetic Fields Considered Spinors in Geometric Algebra?

    Hi, I'm trying to teach myself a bit about spinors, mainly from reading about geometric algebra. There is something that I can't figure out though. According to GA, spinors are elements of the even graded subalgebra, so scalars, bivectors and so on. But the electromagnetic field is a bivector...
  32. F

    Need a bit of help finding a good textbook

    I am currently (considered) a junior in high school having just finished my sophomore year. I will be taking AP Calc BC, Physics C (both units), along with Computer Science 1 and 2 at a community college. I have a strong background in computational problem solving and am fluent in C++, Java...
  33. Z

    Bit of a Frivolous Question - Doing Math in Pen?

    At the university level, is one expected to complete math assignments using ink? Maybe a laughable question, but I've heard different things from different people, from "you will never use a pencil after high school" to "math is a different story", etc. I ask because I've gotten kind of used...
  34. S

    Supposed to be simple but seems a bit tricky

    Let f:{R^n} \to R be a continuous function on some D \subset {R^n}. Now, define epi\left( f \right) = \left\{ {\left( {x,r} \right) \in {R^{n + 1}}:x \in {R^n},r \ge f\left( x \right)} \right\} I want to prove to myself (not homework) that if D has a non-empty interior (that is, there exist...
  35. J

    Mastering Tricky Integrals: Solving sqrt(cot[x])dx with a Substitution

    a bit tricky integral! Homework Statement Integral of (sqrt(cot[x])dx) Homework Equations I just need a hint :) The Attempt at a Solution
  36. S

    How Do You Design a 4-Bit ALU with Basic Logic Gates?

    Homework Statement HI This 4 bit ALU requires 8 functions in a bit slice, and satisfies following criteria Also, it can only be constructed via basic logic gate..and,or,not,xor... No filp-flop...etc. S1 S2 S3 OUTPUT 0 0 0 Shift A Through (X = A) 0 0 1 Shift input A Left (X = A...
  37. T

    A bit of help with KCL and ohms law please

    i have attached a picture showing the problem; just wanting to know if my working out and reasoning is correct please. http://img29.imageshack.us/img29/5412/questionsq.jpg The Attempt at a Solution i have used KCL to answer (a) and (b) and have answers 0.6 and 1 respectively. for (c) and (d)...
  38. K

    Learn a bit more about triality of SO

    I would like to learn a bit more about triality of SO (8) as discussed in this http://en.wikipedia.org/wiki/SO%288%29" . Especially the article says: What do they mean by outer automorphism? How does this automorphism connect the three representations? What is meant by vector...
  39. F

    A four bit adder logic circuit block diagram

    pretty new to this whole computer architure thing, so i appreciate the answers given to my previous question, went through a lecture today in class, came out pretty clueless...what i would like to know is how exactly would the block diagram for a four bit adder circuit look? thank you for...
  40. M

    Spring, resonance frequency and a bit of fun

    Homework Statement The Hungarian national highway M7 is made of concrete blocks 4m long. The joints have a small gap. Józsi have a mass of 80 kg. He owns a Polski Fiat, which is lowered by 10 cm when he sits in. At what speed would Józsi's car disintegrate? Homework Equations v =...
  41. M

    A Bit of Help With Peak Current Flowing with Inductor Please

    Hi can somebody help me with part B of this question please? :) I already did part a) and I found the peak current to be 31.1 mA, and the power rating required to be 4.84 W. For part B I know the current for inductance is I=(1/L)\intVdt and I know V=V0sin(wt), however with only this...
  42. I

    Engineering Creating a 4 bit full adder logic circuit

    Hello, i had a quick question, basically i am trying to build a 4 bit full adder logic circuit on a motherboard. i been trying to research but i came up empty...i would like to know what are the exact parts that i need to successfully build this logic circuit? thanks..
  43. N

    How Can Bit Operations Simplify Conditional Checks in C?

    Homework Statement I want to write the following if statement into simply manipulations using the bit operations: ! ^ & | << >> ~ + Given an x... if ( x == -1 || x == 0) return -1; else return 0; I am dealing with 32-bit integers. How do I go about doing this? (Note: -1 is...
  44. N

    Counting Bits To Left/Right in 32-bit Integer Using Bit Operations

    Homework Statement I am wondering is there a way to count the number of bits to the left or right of a given 1 in a 32-bit integer? For example, if I give the function the number 32 = 0b100000, there are 5 bits to the right of the 1 and hence, 26 bits to the left of the 1. The catch...
  45. N

    Efficiently Count Bits in 32-bit Integers using Bit Operations

    Hi all, I am wondering is there a way to count the number of bits to the left or right of a given 1 in a 32-bit integer? For example, if I give the function the number 32 = 0b100000, there are 5 bits to the right of the 1 and hence, 26 bits to the left of the 1. The catch is, is there a way...
  46. Vectronix

    Need a bit more information about second-order tensors

    I am aware that a vector is a first-order tensor, and that a second-order tensor has nine components in three-space, but can someone tell me more about the directional quantities that are associated with these nine components? Are they still unit vectors? Can a second order tensor be written as...
  47. M

    Introduction, a bit long and Advice

    Hello all, I'll start with the beginning to give the best overall picture. I was born and raised in a religious cult. The impact on my life due to this has been significant as one could imagine. I'll leave the religious identity out as this isn't the forum for it. With such an upbringing...
  48. Ivan Seeking

    News Is Obama a Socialist or a Capitalist?

    Many here are surely familiar with the claims that Obama is a closet socialist. What is funny about this is that I have a friend who calls himself a true socialist. In fact, formally he is probably a Marxist. He is well-studied in political philosophy. He can't stand the evil capitalist...
  49. D

    How do I compute the moment in my statics assignment?

    Statics assignment a bit urgent So here is my assignment. i wish that someone could help me. now i know that this system is statically determinate and that i can compute the forces. my problem is that i cannot figure out how i can compute the moment. the Aim of the assignment is to find all...
  50. F

    Injective Affine Linear Map for (Z/2Z)^3 to (Z/2Z)^3 Sending (1,1,1) to (0,0,0)

    What is the number of bit permutations of the set {0,1}n and the number of circular right shifts of the set {0,1}n. I think the number of bit permuations is 2n, so is there 4 bit permutations here? Namely (0,0), (0,1), (1,0) and (1,1). And the right shift is just sending each element one space...
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