Questions tagged [propagation]
The propagation tag has no usage guidance.
83
questions
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1answer
28 views
Propagation delay in shift register - in the context of a serial adder
The first figure (from Fundamentals of Logic Design, Roth/Kinney, 6th Ed, p.404) shows a serial adder which feeds in operand bits and stores the sum, and uses a D flip-flop to store the carry-out from ...
0
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0answers
20 views
Effective Medium approximation of wet asphalt
So I'm trying to model the effects of wet and dry road surfaces for mm wave communication. My first attempt was to model the road as dry asphalt covered with a thin layer of water, but I'm not sure ...
0
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0answers
15 views
Measuring time propagation of NAND gate with different inputs
I want to measure time propagation of the signal in an NAND gate and I'm getting confused about how I should measure it. Should I take a point in time where both of the inputs changes simultaneously ...
0
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0answers
23 views
Clarity on maximum clocking frequency
This is homework question but i just need clarity on a few things. I have to compare 2 bit and 3 bit 7474 circuit with 74HC74 version. I have to make the comparison using datasheets for the flips ...
0
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1answer
39 views
Fast decoder with low propagation delay
I need to use a fast decoder to communicate with a SRAM memory, CY7C1041GN. The circuit I need to implement is the circuit suggested in the Example #5 of the document AN2408 .The suggested decoder in ...
0
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1answer
31 views
CAN Transceiver Interconnection to MCU (Tx, Rx and Propagation Delay)
I am working on CAN Transceiver and its connection to Micro controller (Hardware Perspective only).
Referring this AppNote - What is CAN?
My questions :
In the above image, I see CAN transceiver ...
1
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1answer
71 views
The explanation about why do we define the formula of Characteristic impedance,propagation constant and Velocity propagation
There is a long transmission line
1.Characteristic impedance \$Z_C=\sqrt{\frac{z}{y}}=\sqrt{\frac{impedance}{admittance}}\$,and in the lossless line,\$Z_C=\sqrt{\frac{L}{C}}\$
2.propagation ...
1
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2answers
72 views
Why are E and B field in phase in far-field electromagnetic wave propagation?
I am very frustrated with the fact that the E and B field of an EM wave are in phase in the far-field case.
Before I get into this question I am letting you know that I already read this link related ...
2
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1answer
124 views
Night-time Shortwave radio broadcast
I recently read an article from https://www.fcc.gov/media/radio/am-stations-at-night
It says:
During daytime hours when ionospheric reflection does not occur to any great degree, AM signals travel ...
7
votes
2answers
1k views
Why is propagation delay a function of supply voltage?
In the context of FPGAs, it was brought to my attention today that propagation delay varies with supply voltage. When I asked why this was so, one of the FPGA designers stated that a logic gate is ...
0
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0answers
34 views
TEM Propagation in Infinite Ferrit Medium
I have realised a question on Collin's Foundations of Microwave Engineering book which is related to TEM propagation in infinite ferrit medium.
I could not find a way to establish to relate positive ...
2
votes
3answers
335 views
Voltage propagation along a wire
Let's say you have a wire connected to a device that you can switch between high-voltage and ground voltage. The wire is not connected to anything on the other end. You're observing the voltage in two ...
1
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0answers
103 views
How to read polar coordinates of radiation pattern
I have a PCB antenna which datasheet provides the following radiation pattern graphs:
There seems to be a "weak" direction which the antenna signals is going to be very weak.
Which direction is the "...
0
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1answer
29 views
Guided propagation in transmission lines
Can you help me on understanding why we may say this transmission line the propagation is guided and there is not any radiation?
It is a 2-conductors transmission line, in which the conductors are ...
0
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1answer
43 views
Zeros in radiation of Smart Antennas
I have an exercise from a textbook about smart antennas. I think I have the right approach to solve this kind of problem. However, I'm not quite sure if I'm handling it correctly due to the additional ...
3
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3answers
732 views
Do I need to maintain source of a signal till it reaches the destination?
If I send a signal through a wire having delay of 10ms, then should I need to maintain the source of the signal till it reaches the destination or can I change after, say, 2ms and send the next signal....
0
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0answers
43 views
Propagation delay in full adder models
From my last question Propgation delay
I tried to solve for the time delay that occurs at the last carry
Not sure if I have done it right .. Please correct me if I m wrong
0
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1answer
211 views
Propgation delay
I want to compare performance of 4-bit full adder vs sequantial (serial ) adder with one D flip flop ..
The two models are in the followig figures
Combinational adder:
Serial adder:
Lets say in ...
12
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4answers
1k views
How is it possible to drive VGA displays at such high pixel clock frequencies?
I'm working on a digital circuit using discrete components to drive a 640x480 VGA display in a 80x30 text mode.
For a 640x480 display, the pixel clock is 25.175MHz, which has a period around 40ns. I ...
0
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2answers
169 views
What is the mode of a square waveguide \$TE_{11}\$ that is deformed into a circle?
I am trying to solve the 2013 paper set by ISRO for electrical engineers. I want some help to solve Question no 17 is correct.
So I don't even know how to approach the problem, what will be the new ...
0
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1answer
420 views
How to understand Transmission and Propagation delay formula
I have three questions below. I would like to understand how their respective answers were reached, this is a question in my current class and everyone in the class has A-Level mathematics experience -...
4
votes
1answer
84 views
What kind of modulation technique and carrier frequency is used for interplanetary communication such as between the Earth and Mars? [closed]
I have just come across this wind sound coming from pressure sensor of Insight lander which is in Mars at the moment.
I know basically that AM, FM, PSK, FSK ect. all have disadvantages and advantages ...
0
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2answers
271 views
how to calculate the tpdhl / tpdlh for any given circuit
i am struggling on calculating the tpdhl / tplh i dont know how to calculate is there any algorethim for the way we calculate the time propagation high to low etc.. several questions asking to take ...
-5
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1answer
50 views
wave propagation ( pict) [closed]
Can someone explain to me what is a meaning of the starred items in this picture?
1
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1answer
235 views
Calculate radiation power of an antenna in respect to a given antenna radiation pattern and a given angle
I work on a program that simulates the wave propagation of high frequency electromagnetic waves (2.4 or 5 GHz Bands) in 3D. I use a ray launching approach, where the emitted rays approximate the ...
1
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1answer
46 views
True near field distance for a short monopole antenna
Antenna properties:
Height x Diameter = 3.3 inches x 1.4 inches
Test Frequency: 900 MHz
(Wavelength = 33 cm or 13 inches)
I see some conflicting formulas to calculate the near field distance for ...
1
vote
1answer
46 views
Decide coherent time and fade duration through empirical studies on the channel and relate them to channel modeling
I. Scenario:
TX floating in the lossy heterogeneous medium with undetermined positions within a limited region;
RX fixed in the air and closed to the boundary of air-lossy medium;
Frequency: 500 MHz
...
0
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2answers
787 views
How does an RS-latch work in the presence of propagation delays?
I've long wondered how an RS-latch can work, given the existence of propagation delays.
If the nor-gates have non-zero propagation delays (aka gate delays), wouldn't it need to be the case that:
The ...
-3
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1answer
2k views
calculating propagation delay
We assume that every gate's delay is (microsecond). what is total propagation delay?
0
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2answers
180 views
Measure S21 between 2 antennas at certain frequency using a Spectrum Analyzer
RX antenna is connected to the Spectrum Analyzer whose reading is regarded as P_RX. TX antenna is connected to a transceiver module that is set to work at the target frequency and emit certain power (...
0
votes
1answer
68 views
How very high frequencies (VHF) are propagated during night over large distances?
I am new in telecomunications and this question just came up today and I coudn't find an explanation.
Here is the most common model for the ionosphere:
The ionosphere layer E is the main resposible ...
0
votes
1answer
489 views
Ripple carry adder doubt
In a 4 bit ripple carry adder 4 full adders are connected serially, one FA waits for the carry input from the previous FA. My question is, when calculating the propagation delay, should we assume that ...
0
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1answer
171 views
Impulse shorter than propagation delay
In an exercise I got an example circuit
For one question, there is \$S(t_0)=1\$ for just \$T/3\$ (third of propagation delay [confusingly called transmission delay here] of every gate in circuit). ...
0
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1answer
261 views
Does LongleyāRice model model takes into consideration Fresnel zone?
To an extent I understand Fresnel zone.But do know how LongleyāRice model takes Fresnel zone? In other words, how Fresnel zone concepts takes into account by the LongleyāRice model? Any comment would ...
0
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1answer
66 views
Do number of reflections depend on frequency?
Consider there is a transmitter at A and receiver at B and transmitter is transmitting radio waves. Further there are obstacles of different sizes in between A and B. Now if we increase the frequency ...
0
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2answers
81 views
Can we conclude from Friis formula that high frequency mean more loss.
I am trying to understand the Friis transmission formula: https://en.wikipedia.org/wiki/Friis_transmission_equation From the equation in terms of directivity can we conclude that higher the frequency ...
0
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0answers
37 views
Can there a be a situation where two way propagation model is important in GHz range?
I assume that applicability different propagation model for wireless channel depends on the frequency of operation and the kind of obstacles or channel under consideration. My question is can anyone ...
1
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1answer
3k views
Propagation delay in full adder
I'm dealing with a question about an implementation of a full adder with component delays.
tpd(XOR) = 5 ns
tpd(AND) = 2 ns
tpd(OR) = 2 ns
I'm having problems solving for the the propagation delay ...
0
votes
1answer
51 views
How surface refractivity affect radio propagation?
This question is related to the following link and Longley-Rice Propagation Model
https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.453-11-201507-S!!PDF-E.pdf
In the Longley-Rice Propagation Model ...
0
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1answer
371 views
What does 80% or 60% of Fresnel zone mean?
This refers to the link https://en.wikipedia.org/wiki/Fresnel_zone
In the link it is mentioned that:
The rule of thumb is that the primary Fresnel zone would ideally be 80% clear of obstacles, but ...
1
vote
3answers
66 views
What is white-space transmission loss?
This question refers to the link below:
http://www.brighthubengineering.com/consumer-appliances-electronics/102752-the-longley-rice-propagation-model-and-tv-white-space-for-ultra-wifi/
What does this ...
0
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0answers
132 views
Propagation delay and arrival time
I am trying to determine the arrival of signals from 3 separate beacons to point x. I have found the distances from x to each beacon as well the propagating wave speed but I do not know how to ...
0
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0answers
82 views
Signal decimator/down-sample with lowest propagation delay
I would like to frequency-divide a 10 MHz digital signal by a factor of 8 or 16, with the lowest possible propagation delay. I need a propagation delay that is at most 5-10 ns. The best solution I ...
8
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4answers
2k views
Are there types of standard coaxial cable with a propagation velocity of 0.9c? What would be the application?
Reading this answer I was surprised to hear that there are "excellent" kinds of coaxial cable with a propagation speed of 0.9c; 90% the speed of light.
The bargain basement number is about 2/3c, and ...
1
vote
1answer
4k views
Transition time (rise time) and propagation delay
Recently in class I have encountered the following calculation of the propagation delay of the following digital circuit:
Could anyone please explain to me the addition of the rising time of X2 and C?...
5
votes
2answers
124 views
How does modules in an asynchronous circuit know when to signal that their output is ready?
I have recently become fascinated by asynchronous CPUs, which have no central clock and each module instead sends a signal, when their data has been processed. However, I have been wondering how such ...
0
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1answer
76 views
How to calculate latency of integrated product?
Is there a standard model for estimating the additional clocking latency which needs to be applied based on product interconnects?
For example: Lets say a DDR memory has a switching time of 1 ns.
...
0
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1answer
171 views
Complex RSSI dBm calculations with shield
I have a little bit of problem understanding complex attenuation calculations when there is a shield involved between the transmitter and the receiver.
Let's take a simple example:
We have a ...
0
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2answers
834 views
Near field magnetic & electric wave impedance formulas
I am looking for the exact formulas for the impedance of an electric and magnetic wave in the near field region.
We have some approximates:
Zweā 1 / (Ļ * Īµ0 *r)
Zwmā (Ļ * Āµ0 *r)
where r is the ...
1
vote
1answer
837 views
Effect of changing the length of an inverter's N-mos transistor on the propagation delay
let's say we want to check the time it takes for our source Vdd to charge a capacitor through an inverter network. changing the width of the P-mos transistor will make more current flow, thus ...
