Questions tagged [bandwidth]

the difference between the upper and lower frequencies in a contiguous set of frequencies

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1answer
2k views

Time-Bandwidth Product

The following text is cited from a textbook, "Spotlight Mode Synthetic Aperture Radar: A Signal Processing Approach", I would like to ask if anyone knows the proof to the following statements, as the ...
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2answers
608 views

How to calculate bandwidth of a wire, “air” or other channels?

I'm really curious of how engineers identify what is the frequency range that could be sent through "wire" as channel? Do they put wire in front of them and make test that consists of sending ...
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1answer
903 views

Bandwidth of M-ary modulation schemes

I am confused with regard to how bandwidth increases with increase in number of bits transmitted for given duration. 1) Usually say in PCM system, when we increase the number of bits (n) for a given ...
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5answers
786 views

Mathematical question that comes out of using bilinear transform

So this is related to the Cookbook and I tried solving it maybe two decades ago, gave up, and was reminded of the unsolved problem. But it's pretty damn straight forward, but I still got slogged down ...
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553 views

Information in GFSK signal

I was measuring a Bluetooth LE Signal, particullary a Channel with center frequency 2402 MHz and Bandwidth of 2 MHz, 2401 - 2403 MHz. Those measurement points are just the highest peaks. In the ...
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256 views

Why does BLE require twice the bandwidth of Bluetooth Classic?

Bluetooth Classic Basic Rate sends data at a rate of 1 Mbps using GFSK modulation in 1 MHz-wide data channels. Bluetooth Low Energy also transmits at that same data rate and modulation, however, it ...
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2answers
8k views

Relation between Bandwidth and Baud-Rate for 8-PSK

I have a query on relationship between Baud Rate and Bandwidth for 8-PSK. In 8-PSK as 3 bits together form a symbol, so Bandwidth = 2R/3 , R is Bit Rate As bit ...
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Interpolation of magnitude of discrete Fourier transform (DFT)

For example for peak frequency finding, it seems valid to use band-limited interpolation methods on the complex DFT bins, or separately on their real and imaginary parts and to calculate the ...
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2answers
587 views

Does “keying on” a sine wave at a zero-crossing reduce its bandwidth?

I understand that a pure sine wave of infinite duration occupies no bandwidth, i.e. it is only the modulation of a carrier that gives it sidebands. Does the exact timing of a sudden modulation make ...
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1answer
485 views

Bandwidth and Bit rate

I'm kind of confused about digital transmission. Is the bandwidth occupied by some digital signal the Fourier spectrum of the bit (pulse) format,or the one determined by the bit rate?
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1answer
592 views

How does one compute the band width of a signal in the time domain $x(t)$?

Sorry if this is a super easy question, I am really not a signals guy (more of a statistician, computer scientist). But I was trying to reconstruct/learn a sinusoidal function $x(t)$ with linear ...
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2answers
8k views

What is the definition of the bandwidth of a signal?

I was reading over the famous Nyquist–Shannon sampling theorem and I was trying to understand what the term bandwidth meant rigorously (exactly) with no ambiguity. In this site the define it as follow:...
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Computing overall bitrate of a transmitter with a two chunks package

I'm programming a digital communication system in MATLAB and I have a two chunk package, let's say a header and a body, and I'm using a different channel code for each chunk, i. e. BHC1 and BCH2. But ...
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1answer
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Correct way to add AWGN to a signal

I have a signal, S whose bandwidth is bw Hertz and is sampled at fs Hertz. To contaminate it with a noise corresponding to SNR <...
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2answers
921 views

What does $[-\pi \; \pi]$ band-limited signal mean?

I know that a band-limited signal is a signal which have a limited set of frequencies. What is then the relation between band limiting and $[-\pi \; \pi]$ since $-\pi$ and $\pi$ are related to ...
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1answer
93 views

Why the bandwidth of the system with the minimum-order observer is higher than the full-order observer?

In Ogata's Modern Control Engineering (5th Ed., page 786) it says: The bandwidth of the system with the minimum-order observer is higher than that of the system with the full-order observer, ...
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1answer
208 views

Bandwidth confusion

Let's imagine that I took a Fourier analysis of a random voice signal that I want to sample and plotted it's frequency components in frequency domain (frequency vs amplitude). Now I want to sample it. ...
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2answers
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What is the definition of small/large signal bandwidth?

What is the definition of 'small signal bandwidth' and 'large signal bandwidth'? If I google them, I only encounter them in an electrical context (transistors etc.). However, I am looking for a ...
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81 views

Conditions for finite bandwidth

I'd like to know which conditions must be satisfied in order to get a signal with a finite bandwidth. Thank you for your time.
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268 views

How does bandwidth relate to the bitrate?

This might be a really trivial question, but I can't wrap my head around it. In almost every textbook, we're told that bandwidth (among power and noise), is the factor for both range and bitrate. I'...
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How does bandwidth affect a modulated digital signal? [duplicate]

I'm currently reading up on how the lower layers of the ISO/OSI model work and I don't quite understand how broadband communication works yet. Suppose I want to send some data from point A to point B ...
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4answers
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what does the statement “band limited signal of 5 KHz” mean

A band limited signal of $5$ kHz is observed at the output node whose sampling frequency is $600$ kHz. What is the minimum order of the filter? Does it mean: a signal that is from $0$ to $5$ kHz on ...
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1answer
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Uncertainty principle - Duration bandwidth principle

In one of NPTEL courses about time-frequency analysis, the professor said that the duration bandwidth principle is $\sigma_t^2 \sigma_\omega^2 \ge \frac{1}{4}$. He added that the formula making use ...
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1answer
203 views

Confusion in Normalised Bandwidth of a signal

I know normalised bandwidth can be found from FFT plot of the signal. But I'm confused that at what stage I have to take the FFT. I mean first binary data is input to a convolutional encoder, then to ...
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How do I calculate the bandwidth from a waveform?

Suppose I have a waveform $x(t)$ where $x(t) = 5 + 30\mathrm{cos}(2000\pi t) + 10\mathrm{cos}(6000\pi t)$ that is to be uniformly sampled for digital transmission, how do I calculate the bandwidth of ...
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2answers
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Bandwidth vs. sampling rate of DAC

What is the difference between the sampling rate and the bandwidth of a DAC? I have found in one paper a DAC speced as 15GHz 3dB bandwidth, and 64GS/s sampling rate, and I haven't been able to relate ...
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707 views

bandwidth limited pulse,what window function is it?

I want to know what kind of shape a multiple cycle sine wave pulse ( or maybe the correct term is burst ) should have to have the narrowest bandwidth possible at given pulse width. In the laser ...
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1answer
207 views

Infinite extent of spectrum, but also in time in Oppenheim's Discrete Time Signal Processing?

In Oppenheim's Discrete Time Signal Processing there's on p. 323 no limited band in both time and frequency - wouldn't that violate the Heisenberg Principle?
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1answer
648 views

The essential bandwidth of a rectangular pulse

The problem is to estimate the essential bandwidth of a rectangular pulse \begin{equation} g(t) = \Pi(t/T), \end{equation} Where the essential bandwidth must contain at least $90\%$ of the pulse ...
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1answer
4k views

The necessity of null subcarrier in OFDM?

In looking to LTE specifications, with the subcarrier spacing $\Delta f = 15 \textrm{kHz}$, for bandwidth $10 \textrm{MHz}$, fft size $N_{fft} = 1024$ that needs a sampling rate $F_s \geq 1024 \times ...
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1answer
570 views

Value of power spectral density $N_0$ or effect of scaling bandwidth to SNR

I want to compare performance over AWGN channel of two systems that are exactly identical but their bandwidth. I will talk only about baseband system for sake of simplicity. For more details about ...
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2answers
146 views

Why is bandwidth always limited in a real (physical) channel?

I'm talking about a continuous analog channel. Why can't it support infinite bandwidth? Is there a physics reasons for it say for electrical signals?
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Spectral Effeciency of BPSK

The null-to-null bandwidth of the main lobe of a BPSK signal is twice the symbol rate. BPSK transmits one bit per symbol, so the signal bandwidth is twice the bit rate. That has been shown on a few ...
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268 views

Changing the Bandwidth of a signal of fixed Sampling frequency [closed]

If sampling frequency is fixed, how can I generate a frequency domain signal of a particular bandwidth from a time domain signal of dimension $1\times N$? e.g. if $f_s=100\,\text{kHz}$, how can I ...
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620 views

Guard Interval in OFDM

If I extend the length of the Cyclic Prefix (Guard Interval) in an OFDM signal, the loss in data rate is clear by means of the time domain, but I can't see it in the frequency domain as the BW is ...
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Why does QASK with a same bitrate as BASK use only half of the bandwidth?

I think the title is pretty self explanatory, what else could I add. Why does QASK with a same bitrate as BASK use only half of the bandwidth? Does anybody have an idea about why this is the case? ...
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1answer
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How to sample $f:=f_{1}\cdot f_{2}\cdot…\cdot f_{K}$?

Let $f_{k}$ be $\sigma_{k}$-bandlimited, $k=1,2,...,K$ and define $f:=f_{1}\cdot f_{2}\cdot...\cdot f_{K}$; then how should I choose $T>0$ such that we can recover $f$ from samples $f(nT)$? ...
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Can picking an inappropriate roll-off frequency for a digital filter just alias the roll-off value?

I believe a related question is asked here, but my question deals more with what filter is realized if one fails to consider design parameters relative to sampling rate. In designing an IIR filter we ...
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Does frequency shifting double needed bandwidth? [duplicate]

Suppose we have a low pass signal and it's spectrum is like this: If we define bandwidth as the difference between signal minimum and maximum frequencies, above picture says that the signal has a ...
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2answers
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Why is the bandwidth doubled with AM?

Let's say I have an arbitrary signal which has the following frequency spectrum and a bandwidth of BNF: Now I use Amplitude Modulation to transport the signal. The frequency spectrum will change ...
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1answer
138 views

$Q$ factor refers to what on a lowpass filter? (EE kind of definition)

For what I'm learning, the bandwidth (of a BPF, for example) refers to the $\Delta$ between $f_L$ and $f_H$ at (usually) $-3\textrm{ db}$ from the $f_0$ (from wiki). For a peaking filter instead, $f_L$...
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Signal power and signal-to-noise ratio with repeaters

I am trying to solve this question but I am confused on some aspects When solving part B what power signal will we use. Will we use power signal before repeater 2 or after repeater 2 (x5) When ...
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1answer
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Two question about RBJ Peak filter

I'm new into DSP and Filters in general. Its the first step ahead I do from learning and using a 1-pole IIR basic Low Pass Filter. I'm about to implement for my VST audio application (using C++ and ...
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1answer
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How to calculate the data rate of IEEE 802.15.4 to be 250kbps? [closed]

How to calculate the data rate of IEEE 802.15.4 to be 250 kbps
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2answers
186 views

Total bandwidth in a network calculation

I have data on the number of devices in a wired network and the data rates on links among these devices. I also know the positions of these devices from which I can compute the distances between the ...
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133 views

Zigbee spectrum calculation

I have information related to the wired network topology in a room with the dimensions 50x10x20m. This includes the virtual link information containing source, target and datarate on a particular link....
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1answer
135 views

Is multirate signal processing involved in ADSL?

Telecom companies offer different data rates for home/office purposes depending on the money they pay. How are the telecom people able to control the flow of data of different cables? Say supposing ...
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2answers
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Root mean square bandwidth of a signal with flat spectrum

I am trying to derive a simple expression for root-mean-square bandwidth $B_{\rm rms}$ for a signal that has flat spectral density over its entire bandwidth $B$. The expression for the $B_{\rm rms}$ ...
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3answers
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Bandwidth of lowpass filter?

This article here on the Window method for FIR filter design speaks of the total normalized bandwidth of the lowpass filter in $\textrm{Hz}$ (counting both negative and positive frequencies) What ...
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1answer
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Advantages of 2-VSB vs BPSK?

Both BPSK and 2-VSB transmit one bit of information per smybol and both modulate the real part of the signal. The difference is, as far as I understand, that BPSK does not modulate the imaginary part ...