What is Channel: Definition and 186 Discussions

Channel 4 is a British free-to-air public-service television network with a remit to produce "high quality and distinctive programming". Its headquarters are in London, with a national headquarters in Leeds and creative hubs in Glasgow and Bristol.The channel was established to provide a fourth television service to the United Kingdom in addition to the licence-funded BBC One and BBC Two, and the single commercial broadcasting network ITV.
It began transmission on 2 November 1982, the day after Welsh language broadcaster S4C's launch. Although largely commercially self-funded, it is ultimately publicly owned; originally a subsidiary of the Independent Broadcasting Authority (IBA), the station is now owned and operated by Channel Four Television Corporation, a public corporation of the Department for Digital, Culture, Media and Sport, which was established in 1990 and came into operation in 1993. In 2010, Channel 4 extended service into Wales and became a UK-wide television channel.

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  1. Chronos

    Troubleshooting DoA RAM Chip: 3x2 Tri Channel Set

    I purchased a 6gb set [3x2] tri channel ram chips. One of the chips is apparently doa. It appears replacing it with an identical 2gb chip is not necessarily guaranteed to work. Any suggestions?
  2. M

    Open Channel Flow: Specific Energy

    A trapezoidal channel with bottom width b = 30ft, side slopes m = 2, and flow Q = 5100cfs given, and I am supposed to plot a specific energy curve (E vs y). That part I have done. For the second part, it is given that 3 bridge piers, each 2 ft wide, are spanning the channel. With the same m...
  3. Y

    BPSK singlepath Rayleigh channel

    Homework Statement The aim of this exercise is to derive and simulate the error rate performance of binary PSK when the signal is transmitted over a single-path (or frequency non-selective) slowly fading channel. The frequency-nonselective channel results in multiplicative distortion of the...
  4. K

    Side channel on the headphone jack

    I'm playing around with an oscilloscope and my laptop's headphone jack. I get the tip/ring/ground and measure between them. I also measure between them and an external reference ground. I notice I can see when the battery is charging. That is, if the battery is not in the laptop but the AC is...
  5. Evo

    History History Channel, great review Joking

    History Channel, great review "Joking!" This article at cracked dot com is really spot on and funny to boot. I did find one bad word on the page, so don't read that word. The entire article is worth reading. I especially love their table at the beginning. It made me *snork*. :tongue2...
  6. R

    Troubleshooting a Mini-Hifi Right Channel Audio Issue

    I know this is a physics forum, but someone may be able to help. I have a mini-hifi that I want to use the tape player connections from as an aux in. I've soldered a stereo cable into the connections on the hi-fi as shown in the electronic diagram. The left channel works fine, without any...
  7. F

    Ivy Bridge triple channel memory?

    The Sandy Bridge only has dual channel RAM, which is why the Nehalem pulls ahead in memory-intensive applications and benchmarks. Will the Ivy Bridge include triple-channel memory? The Ivy Bridge is a 22nm die shrink of the Sandy Bridge. And when will the 8-core chips from AMD and Intel be...
  8. rhody

    History History Channel Pilot: Invention USA

    Presenting its programming http://www.tvweek.com/blogs/tvbizwire/2011/05/cable-channel-greenlights-thre.php" Tuesday at the upfronts, History Channel made the announcement that it is greenlighting three new unscripted shows, Deadline.com reported. The new unscripted shows are "Invention USA," in...
  9. mugaliens

    Jay Gray removed from the Golf Channel

    http://sports.yahoo.com/golf/blog/devil_ball_golf/post/Jim-Gray-removed-from-Golf-Channel-coverage-af?urn=golf-323395" ! Did a 21st Century announcer just offend the 19th Century sensibilities of those who would prefer to remain firmly entrenched in the past? Or is Gray really becomming one of...
  10. A

    Operation of a P channel MOSFET

    Why is it that a P channel MOSFET is always operated with Vds < 0 i.e source positive with respect to the drain? The book says that carrier always needs to flow from the source to the drain, but would the reverse operation harm the MOSFET in any way? Please explain. Thanks.
  11. C

    Coding theory - binary symmetric channel

    Hi Let us suppose we transmit the binary digit '1'. The probability of not receiving '1' is p. Thus the probability of receiving '1' is 1-p. Suppose we send a longer code of length n. The probability of this code being received correctly is (1-p)^n. Now I don't understand this next...
  12. M

    MOSFET channel length modulation

    Hi there, I'm a bit beffudled by some of the workings of a MOSFET transistor. First of all, in the saturation region of operation, I understand that the inversion channel is "pinched off" as it approaches the drain. In other words the inversion channel thickness tapers off as it approaches the...
  13. B

    What is a channel in cellular systems

    If a channel is 5Khz for a full duplex system in cellular systems does that mean person A and person B are using the whole 5Khz to communicate? Or can the channel accommodate a lot of people?
  14. D

    Civil engineering - manning's equation through channel

    civil engineering -- manning's equation through channel Homework Statement I'm given the slope S, the flow Q, the n value, and the diameter of the pipe. I am asked if the channel can handle a certain depth D of water. Homework Equations V = (1/n)*R^(2/3) x S^(1/2) The Attempt at a...
  15. N

    Discovery Channel Taken Hostage

    http://www.nytimes.com/2010/09/02/us/02discovery.html Apparently he thinks that if you threaten them, Discovery Channel can single-handedly solve all the world's problems.
  16. E

    Discovery Channel: Universe & Stephen Hawking Show

    I just want to tell everyone that Discovery channel host a show about "Universe and Stephen Hawkins" Really worth watching. It is a mind blowing series of episodes. Do not miss it. Really worthy Things like history of universe, Meaning for its existence , Dark matter, Black holes etc...
  17. H

    What size channel to use to support AC compressor

    I need to replace an air conditioner compressor unit that sits on the 2nd floor walk way on my stilt home in the Florida Keys. The walk way is 24" deep and the original AC unit fit that dimension, however, the new unit is 31" square. When I install the new unit I would like to leave a 18" space...
  18. W

    Is Quantum Teleportation possible without a classical channel?

    (This was first posted to a newsgroup but there were no replies; so I am trying to post it here). I understand quantum teleportation works on qubits, but i can also work on regular bits. Suppose Alice has a message bit S. S is repeatable, because it is a regular bit. Now Alice wants to...
  19. S

    Stresses on Side Face of Channel Section Under Torque

    if there is a torque on a channel section twisting it axially what stresses do u expect to be on a side face..??
  20. S

    What Stresses Are Present on a Twisted Channel Section?

    if there is a torque on a channel section twisting it axially what stresses do u expect to be on the side face ??
  21. W

    Formula to compare the strength of pipe versus C channel

    What I'm trying to do is compare pipe to channel as far as lateral strength. I have just received a patent, 7,707,794. It's for a building system of walls, fences, and buildings using steel channels and pipe posts. The current way to build a high security fence using expanded metal panels...
  22. P

    Qanat (subterranean channel) water profiles

    (First:my english speaking and writingis not good.sorry) i read a paper about Qanat water profile (Modeling of water surface profile in subterranean channel by DQM) and i have a question about it: what is the application of subterranean channel water profiles? where is it usefull?in where?
  23. W

    Wiring a 6 channel audio with a 2 channel RCA

    Hi folks, I'm wanting to buy a PS3 but have nowhere to plug in my audio except through a 5.1 system that's already being used by my PC. So, I decided to make a little box to wire up the two together and switch between them. But I'm having trouble with the switch... here's a nice picture in...
  24. R

    Calculating Water Level Difference in English Channel

    Homework Statement Estimate how much higher the water level is on the French coast than on the English coast when there is an eastward flow through the English Channel at a typical speed of 1m/s. You may assume that the English Channel is approximately 30km wide. Homework Equations An...
  25. dlgoff

    Catch All 182 episodes of How it's Made on the Science Channel!

    If you like the Science Chanel program How it's Made, here you go. Starting now there are going to be showing all of their 182 episodes over the next five days. Here's their schedule. http://science.discovery.com/fansites/howitsmade/episode-guide/episode-guide.html"
  26. Evo

    The Learning Channel: From Education to Exploitation

    I remember when The Learning Channel started and was about knowledge, that was a LONG time ago. There has not been an educational program on there in more years than I can remember. Now they are hosting the Miss America pageant. Their programming is nothing but garbage, programs like The...
  27. Dembadon

    Sci-Fi Science on the Science Channel

    "Sci-Fi Science" on the Science Channel We stumbled across what appears to be a new series on the Science Channel a couple nights ago. Sci-Fi Science, as it's named, is hosted by Dr. Michio Kaku and has only run a few episodes. I was wondering if anyone has seen it. Here is a link to a few...
  28. DaveC426913

    NZ film on Space Channel called Black Sheep

    I am watching a truly awesome NZ film on Space Channel called Black Sheep. "An experiment in genetic engineering turns harmless sheep into blood-thirsty killers that terrorize a sprawling New Zealand farm." Byline: Get ready for the Violence of the Lambs!
  29. Evo

    History Warriors and Lock N Load on History Channel

    I love these shows. I know turbo doesn't have cable, so doesn't get them, so thought he might like the free video online. http://www.history.com/video.do?name=LockNLoad Tell me this Warriors guy doesn't make you think of Russ_Watters. http://www.history.com/video.do?name=warriors...
  30. B

    Comsol-Pressure drop fluid flow in rectangular channel problem

    Dear all, I am trying to solve a simple model with Comsol to find the pressure drop in a rectangular channel W=5mm, h=0.6mm, L=10mm. When i try to set the inlet velocity to 0.5m/s the solver shows the error message "Maximum number of Newton iterations reached". The solver works fine if i set...
  31. Evo

    Ghost Adventures on Travel Channel

    First I don't understand why this show is on the Travel Channel. Some stupid guy that locks himself into supposedly haunted buildings overnight and films himself screaming and pretending to see stuff. For halloween they are doing a "live" broadcast where "viewers" can posts their comments and...
  32. E

    History History Channel' Universe Series - What went wrong?

    History Channel' Universe Series -- What went wrong? I loved watching History Channels Universe Series but as of late it appears to be on the level of a moron. Why they dumb it down to this extreme? I'm insulted and stopped watching it. Can you guys help me complain send them email so they...
  33. Monocerotis

    Sixty Symbols [The Greatest YouTube Channel Ever]

    Last week I found wolfram alpha by random chance and it blew my mind, a couple days later I ran across this channel on youtube, and I can't stop watching their videos. I'm officially saying it's the greatest youtube channel ever. You will love it, trust me...
  34. F

    What is the impact of changing channel size in microfluidic devices?

    HI! I have a question about microfluidic devices. When you enlarge a channel, for example from 100µm to 2mm, is there a big variation of flow rate or back pressure? I can't find the equation to solve this issue. Thank you damien
  35. somasimple

    Potassium Channel ion rate and Gradient

    Hi All, A potassium channel is designed to filter out potassium ions at a maximum rate of 100,000,000 ions s-1 A common concentration (cell's interior) of potassium is 100 mM and 5 mM outside. This means there is 553 water molecules for 1 potassium ion inside (55.3/0.100) and 11,060 water...
  36. M

    Optimizing Channel Section Tolerances for Pin Jointed Machine Design

    I am deisigning a pin jointed machine that uses some standard channel section. I am having difficulty getting consisitency with the channel section (type BS10279:2000 Hot Rolled Steel Channels) dimensions due to the wide nominal tolerances. Is anyone aware of any channel/U -Section that has...
  37. M

    Fluid Dynamics: Flame front in a channel

    A flame front accelerates exponentially in a channel of width 2R with non-slip boundary conditions at the walls. Flame acceleration creates pressure gradient -deltaP/density=exp(sigma*t) (x-direction) directed parallel to the channel walls. Assuming a plane-parallel flow, find velocity...
  38. E

    Carrying capacity of a channel

    Homework Statement A drainage channel is to be made so that its cross section is an isosceles trapezoid. If the sides and bottom are all 1m in length, what angle, theta, will maximize the carrying capacity? Homework Equations Implicit differentation The Attempt at a Solution I...
  39. M

    How to add additional channel for analog TV (Local Community Channel)

    Hi all, My name is michael. I am currently working in a project which is involving the broadcasting of a local community channel. My background is Computer Science engineer, and I somehow is not too good in this particular things. Hope any of you could give me an idea to solve this out...
  40. M

    How to calculate section modulus of channel section

    Hi guys, I am trying to calculate the section modulus of some channel section. I was going to use the value provided on the data sheet but its confusing me because it has values of section modulus in the X and Y axis. Am i right in assuming that i use section mod value where the load is...
  41. N

    Fully Developed Turbulent Channel Flow

    Homework Statement Hey everyone I was wondering if you could help me - is there any known derivation for the volumetric flow rate through a fully developed turbulent channel flow, I've been looking for ages and can't find anything only for laminar flow. thanks in advance nar...
  42. G01

    History Did the Moghuls of India Really Build the World's Largest Cannon?

    History Channel...Arrrggghhh! The History Channel is playing this documentary called, "Earth's Black Hole." During the course of the documentary they ask whether a black hole under the ocean could be responsible for the bermuda triangle... Does anyone edit these things anymore?
  43. S

    How does one feed a two channel transmitter inputs from a tekronix generator ?

    Hey guys I've done my transmitter. it works fine. But, I need to know how to feed it with input from a generator within taking into account that such a transmitter has two channels R+L. shall i use two different generators to feed every single channel ? I really need some help.
  44. C

    Comparison of FEA and closed form solution for fluid velocity in a channel

    I am trying to compare the fluid velocity given by the closed form solution and FEA analysis for fluid flowing through a channel that is 800u long and 100u wide. I am using the equation vmax= (gradP)*(radius)^2/(4*viscosity) I got 8.4cm/s in the former compared to ~10cm/s in the latter...
  45. F

    Entropy (Shannon) - Channel Capacity

    Hi, I am not sure how to count the channel capacity. If a symbol represents 10 bits of information, and a channel can transmit 10 symbols per second, what is the capacity of the channel in bits per second? C = 1 - H[x] How to go from there? Thanks!
  46. S

    Open Channel Flow (mannings equation) rectangular section

    A rectangular concrete-lined channel is 2m wide with Manning's n 0.012 and a bed slope of 0.0025 m/m. Obtain the depth of flow when the discharge is 9m^3/s. Q=V.A I have the discharge but how do I calculate the velocity without the area ?? Once I have the velocity I should be able to work it...
  47. S

    Open Channel Flow (mannings equation)

    A trapezoidal channel with side batters 1:1 and Manning's n value of 0.025 has a bed slope of 0.0045 m/m. When the depth is equal to the bottom width the discharge is 7.5 m^3/s. Calculate the bottom width to the nearest 0.01m. Using mannings equation V= 1/n.R^2/3.S^1/2 S=0.0045 n=0.025...
  48. T

    Ion Life Channel: Sexist Travel Show "Get Out

    Do any of you get this channel? Have you seen the show "Get Out"? It's a travel show where these three girls travel around the world and tell you about it. Oh, and they only wear bikini tops and they only go to tropical areas. I can't get enough of this show. It is so sexist, because these girls...
  49. B

    Cosmos comes to the Science Channel for the last time

    Carl Sagan's Cosmos is going to be shown for the last time on the Science Channel on the 22nd in an all day marathon, starting at 10 in the morning.
  50. Evo

    Discovery Channel ads, do you remember?

    The Evo Child and I were reminiscing over the old Discovery Channel ads last night, so I thought that I would share. Meteors http://www.youtube.com/watch?v=fWo8-FNywMA&feature=related Fish http://www.youtube.com/watch?v=VVSNrAzxxAE&NR=1 Mosquitos...
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