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Questions tagged [bandwidth]

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

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1answer
169 views

What is the meaning of inverse signal bandwidth?

I have been studying the two ray model in communication systems. The text I'm studying has two signals, $u(t)$, which is Line of Sight and $u(t-t')$, which is the reflected signal. It quotes, ...
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2answers
53 views

How to generate random data with a specific bandwidth

I generate some random data (bits, actually, using MATLAB's randi) and then I convert such bits to BPSK (1 and -1). After that, I use a RRC pulse (roll-off factor ...
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17 views

Digital Spectrum Analyzer: Video Bandwidth

I am currently working on a Digital Spectrum Analyzer. We are trying to imitate a hardware Spectrum Analyzer by capturing I/Q data and performing an FFT on it. I am a bit stuck on how to imitate the ...
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25 views

How to add multiple sub bands of frequency into on wide band

Context: I am doing a project where I have to sample a video signal from a monitor with an SDR. The data is coming in for each pixel left to right top to bottom. Since my receiver doesn't have a very ...
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43 views

Do negative frequencies count towards null-to-null bandwidth?

I am aware that negative frequencies do not normally count towards the bandwidth when transmitting in the baseband. However when specifically asked to look at the null-to-null or zero-crossing ...
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1answer
197 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. ...
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1answer
52 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 ...
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1answer
67 views

Representation, Bandwidth and composition of Digital Signals

I have started learning data communication and I'm not able to grasp certain topics. First (i) I know that analog signals are continuous and digital signals are discrete. Analog signal are ...
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1answer
53 views

Separate speech signals that are bandlimitted

I have 2 kind of signals (refer figures) in a folder. One is band limited to 4khz and another is band limited to 8khz, both are with sampling frequency 16khz. I need to separate them. Any idea??
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2answers
120 views

Should I filter before calculating power, if I'm looking for relative changes in power?

I am building a "scanner" sort of program, which reads IQ samples from an rtl-sdr stick, and keeps track of the power on certain frequencies, in certain bands. I am interested in detecting activity ...
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0answers
20 views

Doppler Spread and Doppler Spectrum

I am a bit confused about Doppler spread and Doppler Spectrum. I believe the Doppler spread is related to channel coherence time T_c, so that . Due to inconsistencies and incoherency of the channel, ...
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3answers
48 views

Why bit rate is same in a lower frequency spectrum and higher spectrum?

If there is a spectrum between 0 Mhz - 1 Mhz, bandwidth would be 1 Mhz here and for example with baseband we can send 2000 bps. What I can't understand is if spectrum is 5-6 Mhz instead of 0 - 1 Mhz, ...
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1answer
42 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 ...
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1answer
100 views

Nyquist Maximum data rate formula for PCM

The Nyquist maximum data rate formula for a binary PCM is given by $$C = 2B\log_2L$$ I'm not very sure what "$B$" is here. Is it the bandwidth of the signal being sampled or is it the channel ...
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1answer
66 views

Bandwidth of a finite impulse response filter

In a machine learning application, a model learns to apply a filter h(n) via convolution to a 1-dimensional input signal s(n) (e....
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1answer
140 views

Calculating Data Rate using Bandwidth, Transmission Power, Noise Power Spectrum Density and Channel Gain

I'm a Software Engineering student researching on Load Balancing in IoT and I need to calculate data rate. However, I don't know how to use these values to attain data rate despite searching on the ...
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16 views

What is a transmission rate of 802.11a WIFI radio?

I am trying to understand the transmission rate at which a WiFi radio sends its packets to other radios ? Like in DSRC (which is 802.11p system) , DSRC Radio broadcasts its message 10 times a second ...
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0answers
86 views

Notch Filter with given Bandwidth

I have to use Matlab with the iirnotch()-function to design a notch filter. The notch should sit at 520Hz, the Bandwidth should be 100Hz and I have a sampling ...
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0answers
19 views

Binary Polar vs 4-PAM Signalling

Why is binary polar signalling not feasible for a data rate of 2.0Mbps within a bandwidth not exceeding 1MHz? Is it due to the fact that binary signalling can only transfer 1 bit of data per symbol ...
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1answer
215 views

Wavelet central frequency

What is the definition of the central frequency of a Wavelet and the bandwidth of a Wavelet? How do they affect the resultant waveform of the wavelet? Thanks.
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1answer
61 views

Appropriate channel bandwidth for my BPSK modulated Psuedo-Random code on direct conversion transceiver

My hardware is an analog device SDR+Xilinx FPGA (sdr = fmcomms4-ebz). The direct conversion transceiver (ad9364) has a tunable channel bandwidth of 200Khz - 56Mhz. I am employing BPSK modulation on a ...
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1answer
252 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 ...
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42 views

Chirp resolution as a function of bandwidth

My question concerns about the Chirp resolution during the crosscorrelation as a function of the sampling rate and available bandwidth. Suppose at a transmitter a chirp signal is transmitted (ranging ...
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1answer
96 views

How is frequency related to data rate?

How does (if it does) frequency affect/relates to Data Rate. Why for example using the same modulation, LoRa (in the physical layer), you get somewhere around 250kbps at 2.4Ghz and only 20kbps at ...
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2answers
448 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&...
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2answers
272 views

Noise power and bandwidth

$$N=kTB$$ In this formula for calculating noise power, why do we use the total bandwidth of the system? I mean our signal is at $f_0$ carrier frequency, why is it effected by a large bandwidth and ...
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3answers
781 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 ...
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1answer
427 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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1answer
1k views

Passband vs Baseband Bandwidth

Bandwidth is the difference between the upper and lower frequencies in a continuous band of frequencies. A key characteristic of bandwidth is that any band of a given width can carry the same ...
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1answer
49 views

Bandwidth of the Derivative of a Message [duplicate]

If I have a message signal $m(t)$ and it has a bandwidth $B$. I know that the bandwidth of $m^N(t)$ is $NB$. But what is the bandwidth of $\frac{d m(t)}{dt}$? Thanks!
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1answer
137 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 ...
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1answer
57 views

What is an intuitive understanding of the difference between the minimum required bandwidth and actual bandwidth?

When using for example, polar signaling of full width rectangular pulses, the bandwidth is equal to the pulse rate $Rb$, which is also the bit rate. $B=R_b$ for full width rectangular pulses. But ...
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2answers
19k 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 ...
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2answers
404 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 ...
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2answers
386 views

Quantization level versus bandwidth [closed]

Why is it that increasing the number of quantization levels $L$ results in an increase in the signal's bandwidth?
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2answers
122 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 ...
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2answers
63 views

Modulation and allocation in GSM900

I want to do one project and I just want to make sure that I've understood correctly. Human's voice frequency is around 85-255Hz. When we talk on phone, carrier is modulated with voice signal in ...
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2answers
421 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. ...
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1answer
846 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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0answers
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How can I design a PI controller for a closed loop system, which requires a bandwidth equal to the natural frequency and a set Phase Margin?

For a school project I have to hand in a small report on a this problem. I've been studying so much for it but right now I'm just mixing up everything I've seen and just don't know where to start. I'd ...
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2answers
304 views

Short length windowed sinc filter

I have a 50-60Hz signal being sampled at a frequency of 25 kHz & I'm trying to filter all frequencies beyond 70 Hz with a reasonable steep transition band (approx 4 Hz) & good attenuation (~40+...
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1answer
405 views

Condition for modelling noise as white noise

I am reading a book on Communication System by Simon Haykin. In the topic of white noise there is a paragraph "We may state that as long as the bandwidth of noise process at input of a system is ...
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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 ...
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2answers
87 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 ...
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2answers
518 views

Bandwidth of product of two signals

POINT 1: According to convolution theorem, if g1(t) has a bandwidth B1 and g2(t) has a bandwidth B2, then product g1(t)g2(t) has a bandwidth = B1 + B2. POINT 2: Now, consider an AM waveform s(t)=g(t)...
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1answer
359 views

Estimating the bandwidth of various signals

I am trying to estimate the bandwidth of different signals, with different modulations, as seen in a PSD graph. I've heard about a "$3\ \rm dB$ rule" in this context. I don't need extreme accuracy. ...
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0answers
131 views

Parseval's Theorm and Effective Bandwidth

This question says that RMS bandwidth (effective bandwidth) is defined based on the carrier frequency of a signal. This makes intuitive sense to me that the carrier frequency shouldn't determine the ...
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0answers
221 views

The number of bits per symbol is less than one

For a channel of bandwidth B Hz and signal-to-noise ratio of S/N, i have used Shannon-formula to calculate the maximum channel capacity C. For transmitting at the nyquist baud rate (2 symbol/sec), ...
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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. ...
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1answer
288 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 ...