What is Bandwidth: Definition and 141 Discussions

In computing, bandwidth is the maximum rate of data transfer across a given path. Bandwidth may be characterized as network bandwidth, data bandwidth, or digital bandwidth.This definition of bandwidth is in contrast to the field of signal processing, wireless communications, modem data transmission, digital communications, and electronics, in which bandwidth is used to refer to analog signal bandwidth measured in hertz, meaning the frequency range between lowest and highest attainable frequency while meeting a well-defined impairment level in signal power. The actual bit rate that can be achieved depends not only on the signal bandwidth but also on the noise on the channel.

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  1. S

    Calculating Bandwidth of AM Signal with Dual Cosine Modulation

    Homework Statement What is the bandwidth of an AM signal if the modulating signal is x(t)=cos(2pi70t)+cos(2pi90t) and the carrier frequency is 10kHz? Homework Equations The Attempt at a Solution The carrier frequency is irrelevant because it just means the signal's spectrum is...
  2. P

    Bandwidth of Space: Threshold Capacity and Limitations

    Bandwidth of space! Can anyone tell me what might be the bandwidth of a m3 of space or air. As we can tell the b/w of Cu wire is in MBps , ethernet cables in GBps and that of optical fibre is around TBps ; is there any way to find out or any formula to calculate the threshold capacity of...
  3. B

    Comparing Bandwidth: PCI Bus vs. FireWire (IEEE 1394)

    The PCI bus found in many computers transmits 64 bits per clock cycle at 33MHz. How does the bandwidth of the PCI bus compare to the serial FireWire (IEEE 1394) serial bus specification, which is 400 Mbits per second? a. The FireWire serial bus is better. b. The PCI bus is better. c. They...
  4. P

    Tradeoff Bet. SNR and Bandwidth.

    I read in my analog communication book: "A relatively small increase in bandwidth buys a large advantage in terms of reduced transmission power. But a large increase in transmitted power buys a meager advantage in bandwidth reduction. Hence, in practice, the exchange between B and SNR is...
  5. N

    CDMA: Exploring Bandwidth Allocation & Capacity

    Hi! I've been reading up on FDMA and CDMA and wondering why is it that in CDMA, each message is spread over the entire bandwidth allotted instead of using a single range of frequencies (say, alloted to one user in FDMA), for several users (by assigning a unique code to each of them)? Why...
  6. E

    Relationships between bandwidth, Fourier trans & digital modulations

    HiHo! W. Stallings's "Wireless Communications & Networks, 2nd edition" explains the relationships between bandwidth and Fourier transformation by depicting a square wave. The square wave is approximated with a Fourier series having several sine terms. The bandwidth is then defined by the...
  7. M

    Converting laser fwhm bandwidth in m to hz

    hi, pls can someone help me with converting FWHM bandwidth of a laser from metres to hertz
  8. M

    Can Someone Help Me Get Started With Amplifier Bandwidth Question

    The question is: To tell you the truth I don't know where to start, I have read over all the teacher's notes and the chapters in the book, and I haven't seen a question similar to this at all. I am not even sure I quite get the question. Can someone help get me started please? Thanks!
  9. M

    Estimating Bandwidth for a Low-Pass Filter Using Real and Complex Numbers

    Hi, this is a problem I am trying to do: So I found that at 3dB, V0=0.7079Vi and I wasn't sure if I should use real numbers or complex numbers, I did both, I'll show the real one: Vo/Vi=0.7079=R/(R+1/wc)=Rwc/(Rwc+1)...I can solve for w, but this will only give one answer, when I use complex...
  10. G

    Op amp bandwidth and gain problem

    Could sb explain to me how to calculate the 3db frequency of the inverting op amp, please? 1. For non-inverting op amp If Bandwidth gain product is 1.5x10^6 Hz and gain is 20dB then the F3db is given by Bandwidth gain product over 20. It equals 150kHz. 2. For inverting op amp the F3db is...
  11. S

    Is the Internet backbone running out of bandwidth?

    I keep running into reports that within a year or so, the current system will be unable to sustain the rate of growth of bandwidth demand. Projections range from "the internet will become little more than a toy" (a paraphrase), to predictions of brownouts or other limitations. It seems that...
  12. A

    Gain Bandwidth Product: Voltage & dB Gain Explained

    If anyone know pls tell me in Gain bandwidth product, gain in what manner (dB or voltage gain (Vo/Vi)) ?
  13. A

    Gain Bandwidth Product: dB or Voltage Gain?

    If anyone know pls tell me in Gain bandwidth product, gain in what manner (dB or voltage gain (Vo/Vi)) ?
  14. J

    Amateur radio + typical bandwidth of RTTY, PSK31, FSK

    Does anyone know what the typical bandwidth of the RTTY, PSK31 and FSK amateur radio transmission schemes are ?
  15. F

    Can One File Really Bring a T1 Line to Its Knees?

    Howdy all. I have a somewhat tenuous relation with our IT department. Basically because they think they are the only ones who know what happens inside a computer. It's an annoyance usually, but every once in a while, something comes up that makes me think they are complete buffoons/idiots...
  16. G

    Bandwidth Problem: Increase Gain & Keep Constant

    hi, I've got simple circuit with noninverting op amp. There are two resistors by which gain is set. And as far as I know the product of bandwidth and gain constant. That is, if we increase the gain the bandwidth decreses and if we decrease the gain , bandwidth increses. The problem is that I am...
  17. R

    Bandwidth of the spread signal

    Homework Statement Given the user date 1000110, we have a spread sequence of 1010110 0101001 0101001 0101001 1010110 1010110 0101001 using DSSS. What is the chipping sequence we used in this DSSS? Assuming the bandwidth of the user data is 50MHz, what is the bandwidth of the spread signal...
  18. C

    Graphing Resistance vs. Bandwidth, why wouldn't go throught the origin?

    I am using Excel and plotting a line of best fit for Resistance vs. Bandwidth. I used the LINEST function to get my values, and it shows that it would cross the y-intercept at around 288 Hz. I am just wondering why when using resistance vs bandwidth it would never cross at the origin. That is...
  19. N

    Photon Bandwidth Frequency Limit: Determined?

    Has an upper frequency limit for the photon ever been determined ?
  20. -Job-

    How can we transmit data using only 2 bits?

    Since this is a Computer Science forum now i thought i'd post this impractical yet interesting take on data transfer. If machine A has to send n bits over to machine B, and A knows the clock speed of B, rather than sending the n bits, A can instead always send two bits bit-1 and bit-2. B...
  21. D

    Why is the bandwidth of the RF filter is wider compared to that of an IF Filter?

    Help!
  22. P

    Understanding of Bandwidth was that it is the Range of Frequencies

    Ok I seem to have a serious problem. My understanding of Bandwidth was that it is the Range of Frequencies that a Radio Receiver can let through its RLC Circuit (or known as the Bandpass Filter). I thought that The set of frequencies are such that they are larger than half the total power...
  23. A

    Tight binding model and bandwidth

    According to tight binding moment, for BCC crystalographic structures (such as Fe), energy E depends on wave vector kx, ky, kz: E(x) = const - 8t cos(kx * a/2)*cos(ky * a/2)*cos(kz * a/2), where t>0 is the model parameter. What is the bandwidth W in terms of parameter t? Can you find kx, kz, and...
  24. F

    Temperature dependence of LED emission bandwidth

    Homework Statement If an LED is used in an optical communications system, explain what would happen to the temporal spread caused by material dispersion in the fibre as the LED is cooledHomework Equations (having trouble using the latex equation editor, sorry) I know that the temporal...
  25. D

    Finding the Bandwidth of PSK Signal

    I've got a signal and I would like to find the 3 dB bandwidth. The signal has a center frequency of f_{c} and a has a bandwidth shaping filter applied to it (ie, a root raised cosine filter). The problem with finding the bandwidth, is that I have no equation for representing a PSK signal...
  26. C

    802.11 is used for short range high bandwidth

    What is there about a particular protocol that defines its range of use? Is there such definition? i.e. 802.11 is used for short range high bandwidth, GSM/EGPRS for long range cellular communications and bluetooth for even shorter range communication on PANs. Is it possible for 802.11 to be...
  27. Simfish

    Does one computer using maximum bandwidth affect other computers on a network?

    If one computer on a LAN network is using maximum bandwidth on, say, downloading a file, then will this affect the bandwidth of other computers on the network? And is bandwidth usually artificially constrained or naturally constrained?
  28. A

    Group Delay & Bandwidth in Color TV Transmitters

    Why is the group delay of a filter inversely proportional to the filter bandwidth? For example in a color TV transmitter the luma signal must be delayed with respect to the chrominance signal before they are added together because the luma signal has a larger bandwidth.
  29. Z

    Capacity vs Bandwidth: Exploring Data Transfer Rates

    hi, 1.please tel me in detail why do we say that for higher capacity we require more bandwidth? higher capacity means more data rate, meaning more bits per seconds(and i know BW is bps) but tell me in terms of frequencies availble in a band..coz we transmit our signal on 1 freq then what it...
  30. J

    Bandwidth Req: Digital vs Analogue Signals

    Hi, I would like to know why do the digital signals require more bandwidth than the original analogue signals to convey the same information ? Is it something to do with the Nyquist Theorem or Shannon's Law ? And what about the harmonics ? Thank you.
  31. C

    What's reading for multimeter set to read dc voltage and bandwidth of 10khz

    Happened to come across this qn: Noise from receiver is measured by rms voltmeter with bandwidth 100khz, and voltmeter reads 2mV. what will be the reading for multimeter set to read dc voltage and bandwidth of 10khz? My ans is 10/100 x 2 = 0.2mV. cos smaller bandwidth reduced by a factor...
  32. R

    Bandwidth of FM Signals: Carson’s Rule

    A satellite telemetry link operating in S-band uses frequency modulation to transmit the value of an analog voltage on the satellite to a receiving Earth station. The voltage has a range from -1.0 volts to +1.0 volts, and a maximum frequency of 1000Hz.The FM modulator on the satellite has a...
  33. L

    What is the Bandwidth of a Second Order System?

    hey all. i read that the definition of the bandwidth of a system is the frequency range up until the signal's power (at DC) drops by -3dB. This obviously only applies to a first order system , right? Surely for a second order - it is defined as the range of frequency up until the power...
  34. DaveC426913

    Network bandwidth troubleshooting

    I continue to have troubles with my residential DSL service. Occasionally (on the order of every half hour or more), my service will just stop working for a minute or so. (Gee, that doesn't sound like a big deal, but really, it makes me want to toss my computer out the window). I'd like to...
  35. D

    Maximum bandwidth of oscilloscope in undergraduate lab

    Well, the lab script said a light wave with 60 MHz is too fast to be detected by oscilloscope so i did some search on the internet on the normal bandwidth(if i am rite, or it is called sampling rate?) is usuall more than 100 MHz. Doesnt this mean that measuring 60 MHz should have no problem at...
  36. I

    Doppler Radar - Bandwidth, Continuous Wave or Pulse?

    Doppler Radar?? Please can someone help me with doppler radar...need to know bandwidth?? Is it usually continuous wave or pulse?? or can it be both?? pretty much just after some general knowledge on doppler radar? thanks in advance!
  37. E

    Signal & System Parameters - Bandwidth Selection

    Hi, Still trying to figure out things with signals and systems... It doesn't go as well as I hoped so please help me... I was checking out a computer program which allows you to specify the parameters of any kind of signal going through any kind of system and then provides you with the...
  38. O

    My isp limited my bandwidth, must find a way around this.

    Well after submitting a very long articulated email to my isp's support page, i got this in response: We limit FTP to 128kbps. Any file transfering program we limit the bandwidth because many of them are bandwidth intensive programs. The rate on it 128kbps. I claimed i needed...
  39. Arctic Fox

    Bandwidth Capacity & Frequency: A Graphical Representation

    Is there a graph or chart somewhere that would show how much bandwidth can be handled at certain frequencies?
  40. D

    Determining Bandwidth & Impedance of an Amplifier

    Ok I have this question that I am finding hard to answer. I understand that you guys won't answer homework questions but all I ask is a little point in the right direction. Heres the question anyway. An amplifier has an open-loop, gain of 10,000 and a bandwith of 2MHz. Its input and output...
  41. P

    How much Bandwidth this forum takes per day and per mo

    i am new to this forum..a programmer who deals with server and related stuff i like to know how much bandwidth this forum takes a day and how many hits a day?
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