Questions tagged [bandwidth]

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

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11
votes
3answers
14k views

What is the bandwidth of a (real) sinusoidal tone, and pulse?

I would like to know how to go about calculating the bandwidth of: A constant (real) sinusoidal tone A (real) sinusoidal pulse. The question is as simple as that, but I am having a hard time with ...
8
votes
5answers
773 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 ...
7
votes
2answers
1k views

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 ...
7
votes
2answers
6k views

What is a $BT$ (Bandwidth-Time) product with reference to modulation?

I would like to know what does Bandwidth-Time product mean. I understand that Bandwidth ($B$) = 1/Symbol Time ($T$), hence $BT = 1$. But how can it vary? What is its significance? e.g. When we say ...
7
votes
2answers
363 views

Bounds of the derivative of a bounded band-limited function

Let $f(t)$ be a function with properties: $$\begin{array}{ll} t\in\mathbf{R}&t\text{ is in reals}\\ f(t)\in\mathbf{R}\text{ for all } t&f(t)\text{ is in reals}\\ |f(t)|<A\text{ for all }t&...
6
votes
1answer
13k views

Bandwidth of a signal using MATLAB

I need to find the bandwidth the signal $x = 50 \operatorname{sinc}(125(t-10))^2$. (Where $\operatorname{sinc}(x)=\dfrac{\sin (\pi x)}{\pi x}$ [normalized] or $\operatorname{sinc}(x)=\dfrac{\sin x}{x}...
6
votes
1answer
5k views

What is the bandwidth of product of two signals?

For signal $x(t)$ with bandwidth $B_x$ and signal $y(t)$ with bandwidth $B_y$, what will the bandwidth of the signal $z(t)=x(t)y(t)$ be?
6
votes
1answer
7k views

what is proper setting for Fb,Fc in Complex morlet wavelet (cmor)?

I am using Cmor-Fb-FC wavelet transform in matlab environment. Fb is bandwidth and Fc is center frequency parameters. with trail and error procedure I select Fb-Fc as 5-1, and I've got rational output....
6
votes
2answers
18k views

Relating bandwidth and wavelength of a carrier

This came from a homework question, which I've solved. Just need some clarification. I am asked to determine the bandwidth in a given amount of spectrum at a given wavelength. To find this, I know ...
6
votes
2answers
6k views

How are time resolution and signal bandwidth related?

I am confused by the dual concepts of time-resolution and bandwidth. Often I will hear that a pulse-compressed radar application 'doesnt have enough BW' for some specific time resolution that is ...
6
votes
3answers
1k views

What is the ideal FIR length, given a specific pulse length?

I am trying to ascertain what the 'ideal' FIR filter length should be, given the pulse length $T_p$ of a windowed sinusoid in noise that I seek to filter. As parameters into an FIR filter that I ...
5
votes
1answer
231 views

Detecting the original bandwidth of upsampled recordings

I have a set of recordings sampled at 16khz, but some of them are upsampled from 11khz and some from 8khz. Quite some of the recordings are noisy. What is the best way to classify the recordings ...
5
votes
1answer
131 views

Bounds of the difference of a bounded band-limited function

For a continuous signal (function), we have Bernstein inequality : $$ |{df(t)}/dt| \le 2AB\pi $$ where $A=\sup|f(t)|$ and $B$ is the bandwidth of $f(t)$. The question is: is there a relationship ...
5
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2answers
2k views

Multiband processing in one pass

I want to split signal in multiple bands and process each band. Number of bands is not yet determined, but it would be more then 6 and less then 11 (depending on the collected results) As ...
5
votes
2answers
340 views

Intersymbol interference due to limited channel bandwidth

What is the difference between limited-bandwidth induced intersymbol interference (ISI) and ISI due to multipath propagation. I noticed that the delay spread in indoor environment is in the range of ...
4
votes
3answers
671 views

Is there a condition for bandpass sampling?

Consider a signal that has lowest frequency component $F_l$ and highest frequency component $F_h$. According to the theory of bandpass sampling, this signal can be sampled and succesfully recoverd if ...
4
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1answer
172 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. ...
4
votes
2answers
556 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 ...
4
votes
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 ...
3
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1answer
2k views

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 ...
3
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1answer
7k views

How are signal bandwidth and MSPS related?

In various software defined radios, there are three important parameters to set when receiving: frequency, bandwidth and MSPS (million samples per second?). What does it mean to receive with a triple ...
3
votes
1answer
865 views

Extracting multiple signals to baseband

How can I extract a signal to baseband? Rather that just listen to one signal at a time, I want to take advantage of my RTL-SDR's 2mhz bandwidth and listen to multiple FM signals at the same time. I ...
3
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2answers
81 views

Could 2 synchronised RX chains be used to receive a signal too wide for just one of them?

Say the goal is to demodulate a "wide" signal, e.g. 300 MHz wide. An SDR is available with a maximum RX bandwidth of 150 MHz (ADC sampling freq. limitation), but it comes with 2 RX channels sharing ...
3
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4answers
7k views

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 ...
3
votes
2answers
649 views

Spectrum analyser and resolution bandwidth

For the preliminary part of a lab I had to do, I was asked the following question: I get how to do 1.1, but with 1.2, I really don't get what's going on; I really would've thought that the resolution ...
2
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1answer
1k views

How bandwidth is used in modulation

In a typical Digital cable environment in the US, the spectrum is divided into 6MHz bands. When a tuner locks to a signal at say 800MHz, I would assume that the band for that signal is 797 - 803 MHz. ...
2
votes
2answers
2k views

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 ...
2
votes
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 ...
2
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1answer
202 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?
2
votes
3answers
252 views

Is there a proof that equal bandwidths have equal information-carrying capacity?

Consider a continuous channel, band-limited to the $[f_{\text{min}},\,f_{\text{max}}]$ frequency window. A well-known statement says that, as far as the dependence on the frequencies, the information-...
2
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4answers
707 views

Difference between the use of 'bandwidth' in DSP and computer networking

As far as I know, bandwidth is measured in herz or 'radian/second' in digital signal processing or in analog communications. But in computer networking it is measured in 'bits/second'. I don't get ...
2
votes
1answer
882 views

Bandwidth of a communication system

As a rule of thumb, the bandwidth of a communication system with a complex signal must be equal to the bit-rate or symbol-rate? Besides, after reading this post, it is not clear for me how a band-...
2
votes
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:...
2
votes
1answer
451 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?
2
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2answers
3k views

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 $B_{\rm rms}$ ...
2
votes
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 ...
2
votes
1answer
14k views

How to calculate bandwidth require for OFDM

I read LTE PHY profile and do not understand the relationship between number of FFT and bandwidth. For example LTE downlink channel bandwidth 1.25MHz and 5MHz have 128 FFTs and 512 FFTs accordingly. ...
2
votes
2answers
111 views

Why can't we just make all wireless networks use integer multiples of base frequency?

I always wondered why transmission capacity depends on bandwidth. For example, let us say that there is an isolated island. In this island, people decide that all wireless networks use frequencies ...
2
votes
1answer
3k views

What is the essential bandwidth with the given function?

Let the function be $$ f(t) = e^{-3t} u(t -1) $$ The criterion is set at 70% of the total signal energy. I know how to find total energy, but not how to find the the $W$ (or frequency) at which the ...
2
votes
1answer
141 views

Laser diode bitrate datasheet

I'm a student studying communications engineering. I'm trying to understand why this particular laser diode is made for 155 Mbps and 622 Mbps. I'm thinking that the bitrate is entirely dependent ...
2
votes
1answer
274 views

“Capacity” concept in Shannon Theorem

I have a question about the Shannon Theorem. According to this theorem the maximum capacity of a link can be calculated with the formula: $$C=B\log_2(1+S/N)$$ where $B$ is the bandwidth and $S/N$ is ...
2
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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 ...
2
votes
2answers
552 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 ...
2
votes
1answer
629 views

Loop bandwidth for symbol timing recovery

I am trying to design the Symbol timing recovery (STR) block of DVBS Receiver. How should I chose the loop bandwidth and damping ratio for determining the loop filter coefficients $k_1$ and $k_2$? ...
2
votes
1answer
468 views

Creating a time domain filter from a frequency domain plot

In figure 11.23 of Monzingo's Introduction to Adaptive Arrays, the author uses a sinewave in the frequency domain to model the amplitude ripple in the passband of a channel of a receiver. What does ...
2
votes
2answers
5k views

Technique of sampling a high-frequency signal (Mhz) with a lower sampling rate (khz)?

I currently have a .wav signal that was recorded at a 48 kHz sample rate, with a central frequency of 5.260 MHz and bandwidth of 4 kHz. I'm trying to get some information from this signal, ...
2
votes
1answer
133 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, $f_L$...
2
votes
1answer
35 views

Find Bandwith from Spectral Efficiency and Eb/N0

to give you a short intro of why I am asking here. My Uni is offering a TeleCom Lecture, I love the topic but all they teach is electronics, the exercise sheets are still TeleCom, we get no supporting ...
2
votes
1answer
115 views

QPSK Data Rate vs Bandwidth at Passband: Why can it only transmit 1 bit per Hz and not 2 bits per Hz?

1) This is a follow up question to the most up-voted answer to this question. 2) The accepted answer is that "QPSK transmits 1 bit per Hz at passband". 3) The theory found in books seems to agree ...
2
votes
0answers
506 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 ...