Questions tagged [bandwidth]

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

Filter by
Sorted by
Tagged with
4
votes
3answers
815 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 ...
8
votes
2answers
473 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&...
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 ...
4
votes
2answers
650 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 ...
2
votes
2answers
9k 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
votes
1answer
719 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
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
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. ...
1
vote
2answers
150 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?
0
votes
2answers
6k views

Essential Bandwidth of rect(t/T)

Here is a question I have been trying to solve: Estimate the "essential bandwidth" of a rectangular pulse $$ g(t) = \operatorname{rect}\left(\frac{t}{T}\right), $$ with $T>0$, where this "...
0
votes
1answer
5k views

How to calculate the required bandwidth from a spectrum diagram? [FM]

For example from this diagram.
8
votes
2answers
7k 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 ...
11
votes
3answers
15k 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 ...
9
votes
5answers
794 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 ...
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}...
3
votes
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 ...
2
votes
1answer
211 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
2answers
9k 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:...
4
votes
1answer
230 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. ...
2
votes
2answers
4k 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 $B_{\rm rms}$ ...
0
votes
2answers
203 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 ...
0
votes
0answers
135 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....
0
votes
2answers
126 views

Why Shannon Theorem has nothing to do with frequency?

According to Shannon theorem $$C= B \log _2(1 + S/N)$$ My question is, why there is no frequency in this formula? Let's say we have 2 channels, both of them have same 20 MHz bandwidth, one is from ...
0
votes
2answers
447 views

Understanding the definition of signal's bandwidth

In class, we have defined bandwidth of a signal as the difference between the maximal and minimal frequency. Also, our tutor explained that the bandwidth indicates how fast the signal is changing. ...
0
votes
1answer
119 views

Bandwidth of a trimmed sinus wave

I generate a sinus which duration is 15ms and frequeuncy of 13KHz. Is its bandwidth is (1/15ms) ? Or in other words, BW = 66.6Hz? I ask that because I have two freqs in my system: 13K & 13.1K. I ...
0
votes
1answer
876 views

How Does the RMS of White Noise Change with Sampling Frequency?

There is an analog system which includes the continuous-time linear equalizer (CTLE). With some .noise analysis the power-spectral density (PSD) of the noise in that system is provided. So let's not ...