# Questions tagged [bandwidth]

Related to signal processing (a measure of the width of a range of frequencies, measured in hertz) or the rate of data transfer(or throughput) measured in bits per second

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### What is the purpose of negative frequencies? [duplicate]

Below you can see the frequency spectrum of a square pulse. But what exactly is the purpose of the negative frequencies? Lets say I have a square pulse with a width of 10ns (f=100MHz) and I want to ...
2answers
409 views

### Determining sensor bandwidth

I'm currently working on a project making use of ultrasonic proximity sensors. Unfortunately it seems as though well-documented ones are very few and far between (when compared to PIC or MOSFET ...
0answers
28 views

### Determining sample rate / bandwidth for a gyroscope with no ODR setting

My understanding is that a sensor's bandwidth should be half it's ODR (the rate at which you sample data). I am working with the BNO055 sensor and trying to get angular velocity from it, which will be ...
0answers
29 views

### Which is the bandwidth of an analog PAM (needed to design an amplifier)?

in a university test, I've been asked to design an amplifier for the following signal: $$s(t)=\left[\sum_{i=1}^{\infty}rect\left(\frac{t-t_i}{T}\right)\right]\cdot Acos\left(2\pi f_0t+\varphi\right)$$ ...
1answer
66 views

### How to calculate the bandwidth of a synchronous bus with overlap in bus transfer and reading next data?

I am working through problems in Saylor Academy's computer architecture course. I can't understand how this kind of problem is solved: Consider a 32-bit synchronous bus with f = 125 Mhz, an 8 nsec ...
0answers
19 views

### How would you get the bandwidth of a MIMO system

I found online that: (SKOGESTAD; POSTLETHWAITE, 2005, p. 81) bandwidth of a MIMO system is the frequency where the maximum singular value of the sensitivity function matrix crosses 0.707 (-3 dB) from ...
4answers
205 views

### Finding the bandwidth of second order lowpass filter

I have a lowpass filter with the transfer function $H(s) = -\frac{3}{3s^2+s+3}$. Converting it to standard form yields $$H(s) = -\frac{1}{s^2+\frac{1}{3}s+1}$$ Comparing this to the standard ...
3answers
118 views

### Why does a channel need to have bandwidth requirement for digital data transmission?

I'm not from EE background and try to understand how digital is sent in a channel as a non-technical audience. Let's say we use fiber optics to transmit digital data 010101...., Since fiber optics use ...
1answer
48 views

### In a shared wireless channel, what are the factors that impact channel gain for each user?

Assume a wireless channel with bandwidth B is shared among N mobile device users. Let's say the size of data transmitted by each device is in the range [100, 1500] Kbits. How does the transmission ...
1answer
1k views

### Bandwidth-Data rate relationship

From a Data Comms textbook: These are the approximate square waves (Fig 3.7a and 3.7b): This is where the effect of changes in bandwidth on data rate is determined: The problem is the explanation/...
1answer
36 views

### how to understand the capacity in binary symetric channel (BSC)

According to the wiki about the BSC (binary symetric channel), given the bit flip rate p, the capacity is derived as : H(p) = -p*log2(p) – (1-p)log2(1-p) C = 1 - H(p). the error probability p ...
1answer
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### Convering bandwidth (frequency) to bit rate without knowledge of the modulation?

How would i convert a bandwidth of say 30kHz to bps if I only know the number of bits per sample (4)? (and I was using a two chanel system). I am assuming it is simply 30KHz * 2 * 4 but this may be ...
0answers
46 views

### why sometimes we need to use Broadband Transmission (Using Modulation)?

I was reading a textbook which says: Baseband transmission requires that we have a low-pass channel, a channel with a bandwidth that starts from zero. This is the case if we have a dedicated medium(...
1answer
530 views

### Ideal wireless channel (coherence time/bandwidth)

Wireless channels can be characterized as either slow or fast fading based on their coherence time and signal length. Similarly, they are either flat fading or frequency selective depending on their ...
1answer
29 views

### Quality factor multiple definitions

On studying RLC circuits, I have come across two definitions of Q factor. One is obviously the measure of selectivity and goes as this: The other is this: Is there any link between these 2 ...
1answer
1k views

### Why does the 802.11b DSSS signal have 22 MHz of channel width? How does the information get spread over that width? [duplicate]

This topic has got me so much confused. In terms of Wi-Fi, when we say the 802.11b has 22 MHz of Channel Bandwidth, what does it mean? When we refer to a particular Channel No. say Channel 1, it has ...
1answer
79 views

### How to find the bandwidth of a function having infinite DC gain?

The transfer function of a plant is given by $G(s) = \frac {10}{s(s+15)}$. After plotting the Bode Plot on Matlab, I can't find the bandwidth of this system since it has infinite DC gain. Could ...
1answer
39 views

### How to find the relative bandwidth /frequency of a aperiodic signal?

I have a transfer function with a fixed cut off frequency and I wanted to apply an input proportional to time(x= cont*time), also the condition is to have a frequency greater than the cut off ...
3answers
738 views

### How does the bandwidth have something to do with speed

They are saying that, if the bandwidth of a certain device becomes narrow, then its speed decreases. However, how does the speed has something to do with the bandwidth? If you are saying that the ...
1answer
164 views

### Constant DC Load Stability and Bandwidth slewrate

For this circuit, how do I know if the rise edge was limited by slew rate or bandwidth? What's the effect of R2 and C2 on bandwidth? -3db of this circuit in simulation is 649 kHz, I know in ...
3answers
131 views

### Why are common mode chokes with 90 ohm @ 100 MHz recommended for USB 2.0 Hi-Speed data lines?

When one looks at common mode chokes for USB 2.0 applications choke manufacturers always recommend CMC with a common mode impedance of 90 ohms @ 100 MHz. Example How does this relate to USB 2.0 ...
6answers
865 views

### Why do we have a limited bandwidth in electronics?

I've been looking around a bit on optical communications and it is said that the main advantage in using optical communications, namely optical fibers, lies in the gigantic bandwidth available, when ...
4answers
14k views

### Why do all digital signals have infinite bandwidth?

Why do digital signals have "infinite bandwidth"? Frequency is the number of cycles per second. I have seen before the formula that bandwidth = maximum frequency - minimum frequency. I ...
0answers
69 views

### Need help understanding RF radio parameters

I am experimenting with the SPSGRF-915 RF transceiver, particularly with the different center frequencies. My question mainly revolves around the situation where multiple devices can transmit at the ...
2answers
214 views

### What are the connection between bandwidth, Nyquist criteria and quantization?

I am trying to solve the below problem and I was not able to find the relation between bandwidth, Nyquist criteria and quantization. Can you please provide some hint? Imagine that the possible ...
1answer
34 views

### Could the OCTC(open circuit time constant) method estimate the current gain bandwidth?

I have already know the OCTC and SCTC method could estimate the cut-off frequency of the voltage gain. Are there any method to estimate the cut-off frequency of the current gain?
0answers
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### Solving PLL Loop BW Transfer Function

𝑍(𝑠)= (1+𝑠.𝐶2.𝑅2)/(𝑠.(𝐴3.𝑠^3+𝐴2.𝑠^2+𝐴1.𝑠+𝐴0) C2 = 0.0000001F R2 = 1000 Ohm A0 = 0.000000106034 A1 = 1.27859848E-12 A2 = 4.5011166848E-18 A3 = 4.31278848E-24 G(𝑠)= (𝐾𝑝𝑑.𝐾𝑣𝑐𝑜.𝑍(𝑠...
0answers
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### LoRa CSS modulation chip rate and bandwidth

In this question, as well as in many other detailed explanations of how LoRa CSS modulation works, each analysis starts by saying that the chip rate, Rc, is equal to the bandwidth BW. Why is that?
3answers
456 views

### Square wave spectrum and knee frequency

There is this rule of thumb to estimate the required bandwidth of a digital signal by its rise time: $$\text{f}_{\text{knee}} = \frac{0.5}{\text{t}_{rise}}$$ This knee frequency is described in "...
0answers
59 views

### What is the derivation for Shannon Hartley theorem?

I know by Hartley's theorem that information is proportional to bandwidth and time. The capacity corresponds to information and bandwidth is there. I don't get how the logarithmic part corresponds to ...
1answer
45 views

### What is the derivation for shot noise current?

The screenshot is taken from Principles of Electronic Communications by Louis E. Frenzel Jr. I don't know where the formula came from and I tried searching, but couldn't seem to find any that I ...
2answers
266 views

### How does widening the frequency band allows us to make faster pulses in a radio link?

I’m new to radio communication and completely ignorant in the topic. I spent some time writing software which includes calculation of the channel capacity (in bits/second or symbols/second or bauds) ...
0answers
36 views

### Spectral properties of QPSK modulation

From what I've read, the spectral properties of the modulation largely depend on the rate of change of the signal phase - "a signal in which the phase changes stepwise has a broad spectrum, well ...
0answers
36 views

### Is bandwidth of cmos comparator important?

The concept of bandwidth is developed based on small-signal analysis. However, comparator works usually under large-signal conditions, and transistors are not in saturation region, since comparator ...
2answers
90 views

### Why does higher bitrate requires higher bandwith?

I try to understand this question since a while and I think I came to an understanding. But I need someone to confirm it. At first, I thought the bitrate was dependent on the frequency (more sines per ...
0answers
35 views

### I am wondering about the relative between Step input and bandwidth

How we can do define the explanation of bandwidth in step input graph? Sorry to not explain about problem deeply, cuz I am newbie about control theory. in book , that explaining smaller 3dB of when ...
1answer
610 views

### Parallel RLC Resonance bandwidth

Good day ,I need help in understanding a practice problem that my professor gave us. A parallel resonant circuit has Q = 20 and is resonant at ωO = 10,000 rad/s. If Zin = 5kΩ at ω = ωO what is ...
3answers
68 views

### Definition of signal bandwidth

From my understanding the bandwidth of an input signal to an ADC is defined as the range of frequencies the signal consists of, which is calculated as the difference between the highest and lowest ...
2answers
69 views

### Does the bandwidth at the receiver really affects the noise in digital modulations?

I know that, in a telecommunicacion system, the AWGN power after going through the receiver filter is $$P_z = KTB$$ where B is the bandwidth of the filter, T is the operating temperature of the ...
1answer
204 views

### How to calculate the 3dB point?

I understand this until the final two lines. How does he get from 27.8766 to 1149.8hz and 7224.7rad/s?
9answers
5k views

### If a square wave has infinite bandwidth, how can we see it on an oscilloscope?

If a square wave requires infinite bandwidth how can we display it on oscilloscopes? Link: Oscilloscope fundamentals.
1answer
109 views

### Op amp advertised as BW = 105MHz, but GBP is actually 70MHz, what's being spec'd differently?

I just came about an op-amp spec where they say, "the Op-amp X is unity-gain stable with a small-signal unity gain bandwidth of 105MHz.." As you continue to read, it then says, "with a ...
1answer
63 views

### Generating a short needle pulse

I have an op-amp with a 100 MHz bandwidth. The input of this o-pamp will be a 65 MHz square wave. Can I expect to get something like a needle looking pulse? Because I am only going to have the first ...
0answers
47 views

### Two amplifiers in cascade

I want to do a simulation with two type amplifiers (PA107DP) in cascade to expand the bandwidth. How can I do ? just I connect the output of first to the input of second (out-one I connect it to -IN ...
2answers
90 views

### Bandwidth vs slew rate

I have some difficulties in understanding the difference between bandwidth and slew rate. I got that we are talking about large or small signal but what if for example the input signal is a PWM one ...
0answers
36 views

### RC noise figure calculation

I would ask for some help with noise figure calculation for circuit attached. It is front end of improvised differential probe that I would like to build. I am aware that simulators such as LTSpice ...
4answers
10k views

### Why do higher frequencies mean higher data rates, and why do we even need frequencies to begin with?

This is regarding wired connections. I have heard that higher frequencies mean higher data rates since there are more cycles per second you can fit more data in per second. That makes sense but I ...
2answers
87 views

### Common emitter bandwidth and probing

I am trying to design a simple RF amplifier for a 1MHz AM signal (for low-power transmission). My modulator (JFET-based) outputs ~...
1answer
142 views

### 2.6 GHz microstrip patch antenna with 100 MHz bandwidth

I'm trying to design a microstrip patch antenna @ 2.6 GHz. The result I got is good but the antenna is very selective and I haven't been able to increase the BW. Currently, the BW is 40 MHz and I ...
5answers
128 views

### Required GBW of an op-amp

So if my Vin signal is of 50kHz and I want a gain of 50, would this mean that the GBW of the op-amp has to be at least 2.5Mhz? What happens if its below 2.5Mhz