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. A

    Estimating Bandwidth of Phase Modulated Signal Using Taylor Series

    Homework Statement Consider the PM (phase modulated) signal, s(t) = Acos(wt+x(t)) where x(t) is the information bearing signal. Assume that |x(t)|< y, which is not necessarily small. Using Taylor's series expansion, derive an estimate for the bandwidth of the PM signal s(t). Homework...
  2. C

    Why does more bandwidth means higher bit rate in digital transmission?

    I'll start with what I do know: Shannon Law gives the theoretical upper limit C_{noisy}=B*log_{2}(1+\frac{S}{N}) if S = N, then C = B As N→∞, C→0 As N→0, C→∞ Nyquist Formula says approximately how many levels are needed to achieve this limit C_{noiseless}=2*B*log_{2}M (If you do not use enough...
  3. S

    Bandwidth & GFSK: Calculate Data Rate & Increase Frequency?

    Hello, I have a doubt how data rate is calculated in GFSK ? I am new to RF. so please describe.my second question is why can"t we change frequency faster for high data rate? a typical 433Mhz transceiver hardly gives 100Kbits only why?
  4. T

    Why is the non-inverting amplifier's bandwidth rating lower than expected?

    Hello, I have a question that I thought some of you may know an answer to. I was recently testing an op amp is several closed-loop feedback configurations. Primarily inverting, and non-inverting. When testing the output voltage of an invertin amplifier, I found that the output signal...
  5. ajayguhan

    Exploring Fibre Optic Bandwidth & Single Mode

    It's given, "fibre optics are thin to accommodate single electromagnetic mode" what do they mean by single electromagnetic mode...? And also mentioned it has high bandwidth, i know that bandwidth is difference of highest and lowest frequencies of the signal. So if fibre optics has high...
  6. P

    Bandwidth to send signal FSK question, question about terminology

    Homework Statement A binary encoded signal with a bit-rate of Rb = 112 kbps is now encoded using polar NRZ baseband encoding and then modulated using binary FSK with a carrier frequency spacing of 10 kHz. What is the bandwidth required to transmit this modulated signal? a.132 kHz b.224...
  7. F

    What is photodetector bandwidth?

    Hi, I would like to know how a detectors bandwidth can be measured? for example, if there is any relation with the produced current or what? I can't understand bandwidth concept. Thank you.
  8. E

    Bandwidth & Bitrate: Exploring the Connection

    Hi all, this question about bandwidth has been bugging me and I haven't been able to find an answer yet. Im not so familiar with the topic so this might be some glitch in my thinking which I hope you guys could clarify: Why is max bitrate in a channel two times its bandwidth? For example...
  9. S

    CE amplifier - How to limit bandwidth?

    When using the CE BJT amplifier configuration, when a shunt capacitor is placed across the collector resistor, how does this act as a bandwidth limiting cap?
  10. trollcast

    Remote Desktop Connection bandwidth usage?

    Is the remote desktop client in windows really bandwidth intensive? We get roughly 16mb/s down and 1mb/s up even at fairly peak times, however as soon as dad goes on his laptop to use his desktop computer back at the office the internet becomes horribly slow, it doesn't seem to be a speed...
  11. S

    What's the bandwidth of the Cosmic Microwave Background radiation?

    What's the bandwidth of CMB and what was the bandwidth of CMB when it was emitted (at the moment when the Universe was 379,000 years old)?
  12. F

    Maximum frequency, not bandwidth?

    Hey In many places on the Internet you can read how the Nyquist frequency must be at least as high as the signals bandwidth in order to properly reconstruct the signal. Isn't this a big misnomer, since it is not the bandwidth, but the highest frequency of the signal that determines the...
  13. T

    Resonance and Bandwidth Question

    So, I've been covering these concepts recently in a few of my classes, and I'm wondering if the bandwidth is always centered on the resonance frequency? I assumed it was. However, in a recent problem given, it is shown that the bandwidth of a band-pass filter was not centered about the...
  14. S

    D/A Communications - Minimum bandwidth of a channel

    Homework Statement Homework Equations The given channel transfer function and PSDs. Note that the capital Pi symbol in the PSD of the message symbolizes the rectangle function so Sm(f) = 8rect(f/8000) The Attempt at a Solution From my understanding, channel noise is not filtered at this...
  15. E

    Incorrect lecture notes relating Bandwidth with speed?

    Hello PF. Thanks for reading. My understanding of Bandwidth in the context in which I learn it (Analogue and Digital Communications) is that it is the spectral width of a signal, BW = f[upper] - f[lower]. However, my lecture notes then define 'fundamental limitations' as, Bandwidth...
  16. D

    Bandwidth at resoance and peak dB level

    Hi, I'm investigating what happens to bandwidth at resonance of a series RLC circuit when each component is doubled. i have simulated the circuits and created a bode plot. You can see from the photos that at resonance the gain peaks at -20.82 dB. I would like to know how to calculate this...
  17. R

    How do I find Bandwidth from looking at Graph?

  18. T

    What is bandwidth in the context of RLC circuits?

    Homework Statement I noticed that bandwidth is the difference between the frequencies that gives half power: But sometimes it is the difference between when the frequency is 0 and the frequency that gives half power: So the definition in my lecture slides states that bandwidth is the...
  19. A

    Relation between bandwidth and ssamplig rate

    greetings, how a sampling rate can define bandwidth required for transmission of that signal.if sampling rate is high then bandwidth requirement is also high,how?
  20. D

    Different bandwidth for different devices

    Hi, I'm trying to diagnose a bandwidth problem on my PC. I'm getting less than half a Mbit when connected to my house's wireless router. However, when i connect to that same router with my phone i get over 4Mb. Both devices were tested on the same website (bandwidth place) so i am certain...
  21. W

    How do i derive the relation between coherence time and bandwidth

    I was just curious, sorry if it is already asked, I was going through a book on photonics and came across the relation coherence time, t = λ*λ/Δλ I did not find any proof of this. Can anyone explain me how this relation is found?
  22. S

    Gain bandwidth product from bode plot

    Can anyone tell me how to find the gain bandwidth product from bode plot of a unity gain circuit for the attached bode plot? I hv attached the circuit and bode plot ...
  23. I

    Gain bandwidth product of unity gain opamp

    i have attached a bode plot and the opamp dc second order lpf circuit. the opamp Tl082 has a gain bandwidth product of 4Mhz according to the datasheet. this circuit has a bandwidth of 414.25khz. can we determine the opamp' individual gain-bandwidth product from this plot ?? if yes , how do we...
  24. C

    RF fundamentals, how does bandwidth affect throughput

    I'm trying to get a basic understanding of RF DAC. If I have a DAC that does 100 MS/s with an 8 bit resolution, this translates to a 800 Mbps throughput. Or is this too simple? Now, how does the bandwith of a channel affect this? Say I have two 5 MHz channels. With two channels there...
  25. Q

    AM (SSB-SC) Signal Bandwidth 941 kHz 20 Hz-19 kHz

    Please help me to find out, what is the bandwidth in (kHz) of an AM (SSB-SC) signal with a carrier frequency of 941 kHz and a baseband signal that has frequency components from 20 Hz to 19 kHz? thanks
  26. M

    Calculate Bandwidth of Filtered Signal

    Homework Statement My message signal is the Fourier Series (x(t)) of a bipolar pulse. This signal passes through the ideal low pass filter, h(f), which has a cutoff frequency of 4Khz. What the baseband bandwidth of the filtered signal? Homework Equations ƩAn*cos(2*pi*n*f0*t), An=...
  27. D

    Digital modulation and RF bandwidth

    Why isn't it possible to invent a custom digital modulation scheme that would use much less RF bandwidth than all the schemes available? What are the limiting factors that do not allow for high data rates to be coded so that the occupied bandwidth is much less than all the others like ASK, PSK...
  28. F

    AM bandwidth determination

    Hello, if I was using an 800Mhz carrier which was modulated with the range of frequencies 200Hz-3.3khz, what would be the total bandwidth ? Would it be 3.1Khz * 2 = 6.2kHz or would it be 6.6kHz ? Thanks for any help.
  29. H

    Helium-Neon LASERS gain bandwidth

    Homework Statement A helium-neon (He-Ne) laser has a gain bandwidth (denoted here as the frequency interval over which the laser gain equals or exceeds the minimum threshold gain) given by ΔG= 1.0 GHz, centred on the λ = 632.8 nm emission wavelength. Show that in order to tune the...
  30. M

    Can Short Pulse Bandwidth Limitations Be Overcome in Radio Transmissions?

    My application is a pulsed radio transmitter. Ideally I would like to be able to use 5 μs pulses spaced about 4 seconds apart. Each pulse would represent 1 bit. So my bit rate (and my symbol rate) would be around 0.25 bps. Just based on signal theory alone I think 0.25 bps would allow for a...
  31. I

    Building a Simple Amplifier Circuit With High Slew Rate and Bandwidth

    Hello all, I have been building a simple amplifier circuit(diagram attached) that will take in a source voltage and use a resistor divider to divide the voltage down on three different ratios, determined by a manual switch- 1/1, 1/4, and 1/40. It goes through a unity gain configuration...
  32. E

    Bandwidth efficiency in m - ary psk

    In M-ary psk Rb=Rs*log M log with base 2 Rb- bit rate Rs - symbol rate then bandwidth required for passband signal is B=Rs and bandwidth effeciency = Rb/B=log M log with base 2. Is the above formula for bandwidth efficiency...
  33. E

    Nyquist bandwidth criterion

    According to Nyquist bandwidth constraint for transmission without ISI , the minimum channel bandwidth should be R/2 symbols /sec, where R symbols /sec is the transmisson rate. If this is correct then i want to know that if this channel cannot support full transmission rate then do we use this...
  34. F

    What Does a 3kHz Bandwidth Mean for a Leased Telephone Line?

    What does it mean if a leased telephone line has a bandwidth of 3kHz? Does it mean any signals traveling alone that line must have frequency components less than or equal to 3kHz? Or does it mean that all the signals' frequency components (assuming time multiplexed) must add up to be less than...
  35. A

    Using op-amps, which have a gain x bandwidth constant

    Using op-amps, which have a gain x bandwidth constant of 500,000, design the following circuits. Include circuit diagrams, the appropriate theory and details of how you calculated the values of all the components used.(i) An inverting amplifier with a gain of 500, having an input impedance of...
  36. A

    Frequency Bandwidth of Detecting and Amplifying

    Homework Statement What must be the frequency bandwidth of the detecting and amplifying steps of a radar system operating at pulse widths of 0.1usec? If the radar is used for ranging (distance measurements), what is the uncertainty in the range? 2. The attempt at a solution Aside from...
  37. M

    Physical explanation of bandwidth (analog)

    Hello friends, I am finding it a bit difficult to comprehend what the author of a famous textbook has written about TV signal band width. Here is the excerpt from his book. Could any of you please explain what exactly he means? I don’t get why the required bandwidth is around 5.5 MHz...
  38. S

    For Amplitude Modulation, it is understood that the bandwidth of a

    For Amplitude Modulation, it is understood that the bandwidth of a passband signal is always twice as much as that of a baseband signal, for example if the bandwidth/max frequency of a message/baseband signal is 1 kHz and a carrier of 1 MHz is modulated with this baseband, then a "sum"...
  39. James889

    Bandwidth vs Bit Rate: What's the Difference?

    Hi, I never really understood this. What are the differences between bandwidth and bit rate ? I understand that they describe the same thing, yet are completely different. How are these related?
  40. A

    Bandwidth vs frequency bandwidth in a network

    I can't translate it 100% correctly, but my course notes describe two different properties of a medium: Literal translation: "The band width." - ? "The band width of frequencies" - as the difference of fmax and fmin What does each exactly refer to, and what's its name in english...
  41. T

    Bandwidth of the baseband signal

    Homework Statement Consider \phi_{FM}(t) = Acos[2\pif_{c}t + k_{f}\int^{t}_{-\infty}m(\alpha)d\alpha] where the message signal is m(t) = 10\picos(2\pif_{0}t) with f_{0} = 4kHz and the carrier is given by c(t) = 10cos(2\pif_{c}t) with f_{c} = 10MHz. The bandwidth of [tex]\phi_{FM}, using...
  42. P

    What is the difference between bandwidth and wavebands?

    My physics book repeatedly refers to the term "waveband" while explaining the bandwidth of AM broadcasts It states that : The bandwidth of AM broadcasts on the LW and MW wavebands is 9kHz. However, I haven't been able to deduce the meanings of the term "bandwidth" and "wavebands" in the...
  43. J

    How to calculate the bandwidth for a Kernel density estimation

    Hello everybody! Since some time I am trying the estimate the density of a set of numbers (in my case the numbers are distances to some object from a laser scanner). As I read, that the kernel density estimation technique is a basic approach for that kind of problem. Different Kernels can...
  44. J

    Null-to-Null Bandwidth of AM Signal (10ms, 1kHz)

    1. What is the null-to-null bandwidth of an AM signal with a single-tone message whose duration is 10ms and whose frequency is 1kHz? 2. Relevant transforms (sorry, I don't know how to include special formula functions that are on the forum here): x(t)cos(ft) <-> 1/2[X(f+f0)+X(f-f0)] Also the...
  45. T

    Bandwidth requirements if the modulation is BFSK?

    Homework Statement A binary signal is filtered with r = 1 and then modulated onto a carrier for transmission at 9600 bps. a) What is the bandwidth requirements if the modulation is BFSK with f1 = 100kHz and f2 = 120kHz? (Note: FSK bandwidth is B = 2fd + (1+r)R ) b) Using the same...
  46. K

    Understanding the Significance of Photodiode Bandwidth | Lab Tips

    What does the bandwiidth of a photodiode signify? I just know that it is related to speed of photodiode, but while dealing with PD practically in lab. , what does its bandwidth tell me ?
  47. Topher925

    Methods to increase bandwidth of a transimpedence amplifier?

    Long story short, I'm trying to "easily" increase the bandwidth of a transimpedance amplifier which is limited by the intrinsic capacitance of the feedback resistor, R. The knee frequency is of course given by f = 1/(2*pi*R*Cr), where Cr is the intrinsic capacitance of the resistor. As...
  48. I

    What is the Relationship Between Bandwidth and RLC Circuit Parameters?

    Homework Statement and Homework Equations I am trying to get from: I_{max}=\sqrt{2}I=\frac{V}{\sqrt{R^2+(\omega L-\frac{1}{\omega C})^2}} to: \Delta\omega=\omega_1-\omega_2=\frac{R}{L} The Attempt at a Solution From the equation above: \sqrt{R^2+(\omega L-\frac{1}{\omega...
  49. S

    What do you mean by bandwidth?

    please explain it in easy language. explain other terms (like freq. spectrum) if u'll use. nd y there is always 3 db shown in its diagram.
  50. M

    RF Detector: Understanding Video Bandwidth

    what is the meaning of Video bandwidh for rf detector?
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