Questions tagged [bandwidth]

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

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Why are all baseband signals low-pass?

A baseband signal is just a signal that has not been used to modify a carrier signal. Now, I have noticed that all baseband signals are low-pass too. Why is that? I can understand why digital baseband ...
1 vote
169 views

What does the bandwidth of a medium even mean?

Whenever the bandwidth of a medium linking two devices is greater than the bandwidth needs of the devices, the link can be shared. Multiplexing is the set of techniques ... Forouzan, Data ...
467 views

Bandwidth of Information Signal

I have trouble finding the bandwidth of a signal. Say I have an info bearing signal m(t)=sinc(2t/pi). I found the fourier transform of the sinc function and found that the angular frequency was 1/pi. ...
1 vote
6k views

Relationship between signal rate, data rate, minimum bandwidth

I need to understand the relationship between bit rate, signal rate and minimum bandwidth. I read in a textbook that We define three cases for relationship between bit rate and signal rate for ...
96 views

Cutoff frequency condition of input signal so that it can be reconstructed , given frequency response (Answer explanation?)

For the following system: We have: $$r(t) = s(t) + Ks(t-\tau)$$ where $|K|< 1$, with the following impulse response $h(t)$ and frequency-response $H(f)$: $$h(t) = \delta_0(t) + K\delta_0(t-\tau)$$ ...
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DAC sampling rate when using DSSS/CDMA

I'm currently not sure if I understood DSSS correctly. Following example: We have a shared RF network with around a thousand of users and we want to use CDMA. The RF link should allow the streaming of ...
1 vote
57 views

Measuring thermal noise of RLC circuit

I am confused about Johnson-Nyquist noise. Specifically, where does bandwidth come in? Thermal noise voltage is usually defined as something like: V^2=4kT∫R(f)df, integrated over a bandwidth. I am ...
1 vote
179 views

Does bandwidth include negative frequencies?

I've seen countless definitions of bandwidth that disregard negative frequencies. Is that done due to the symmetrical nature of a certain signal eg. a cosine or due to the inherent lack of meaning ...
3k 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 ...
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Clarification on video about frequency deviation in phase modulation bandwidth

I am watching this video and at 7:12 he calculates the frequency deviation $\Delta f = f_{c}f_{m}A_{m}$ where the $c$ underscript is for "carrier" and the $m$ underscript is for "...
453 views

Meaning of roll-off factor 0.5 and bandwidth

We currently have a radio that is transmitting at the following RF params: Modulation: OQPSK Data rate: 500Kbps Uplink coding: BCH I am interested in understanding what is the associated uplink ...
1 vote
4k views

Minimum Channel Bandwidth for PCM

Please check if my answer to GATE IN 2010 question 11.20 is correct/can be improved upon. So, every $\frac{1}{f_s}$ sec, a sample is taken. The signal amplitude is quantized into $2^n$ levels such ...
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In the RMS bandwidth equation, why do we have the energy of the signal in the denominator?

In the following equation: $$B_{\rm rms}^2 = \frac{\displaystyle\int_{-\infty}^\infty f^2\lvert G(f)\rvert^2df}{\displaystyle\int_{-\infty}^\infty \lvert G(f)\rvert^2df}.$$ It is not clear why do we ...
181 views

spectral bandwidth of QPSK signal

When running the MATLAB QPSK transmitter and receiver example (found here: QPSK Tx and Rx Example) you can see on the plot of the spectrum that the bandwidth is ~80kHz. If we double click on ...
55 views

Bandwidth transmission for uniform PCM using m-ary PPM

I have a uniform PCM whose bandwidth is W = 1Hz and n = 12 bits, i.e. the transmission bandwidth B_T = n*W = 12Hz. Given this features of the signal, I need to calculate the minimum transmission ...
71 views

LTI system tradeoff between gain, bandwidth, and delay

For first-order LTI systems, the gain-bandwidth constant is often discussed. I've seen the claim that in general, gain and bandwidth don't directly trade off with each other as much as delay. For an ...
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How the bandwidth distance product rule is applied?

I read the following in one reference: A copper wire (twisted pair), the link traditionally associated with low bit rate transmission, is still in use in the modern data centers transmitting data at ...
1 vote
395 views

How to generate wideband Gaussian white noise

I want to generate correlated complex white Gaussian noise signals in MATLAB. What I do is that I take complex Gaussian random variables with unit-variance and multiply them with the desired input ...
132 views

Bounds of higher order derivative of bandlimited signals

Here is a bandlimited function f(t) with bandwidth Ω: The function f(t) is bounded in [-A,A]. Then the bound of the derivative of f(t) is bounded as: |f'(t)|≤2πΩA. So, what is the bound of its n-th ...