Questions tagged [propagation]

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How to measure radio wave penetration and reflection through different mediums

I would like to do a few experiments to test how different EM radiation frequencies (915 MHz to 5 GHz) interact with 3D print filament materials (like PLA, PolyCarbonate, TPU, etc...). Specifically I ...
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What energy/fields if any is generated when radio frequency is passed through a coaxial cable?

I am new here. Just had a question wondering if someone could answer. Let's say I have a generator that can generate RF and send it through a cable (coaxial) if I attached the end of that wire to a ...
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9 votes
3 answers
2k views

What does a chip's propagation delay vary on?

When looking up datasheets on logic gates, propagation delay is usually shown as a range. Sometimes there's a "typical" value in the middle, but there's a min and max listed. On what does ...
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Why does short band (high frequency) radio travel longer than low frequency?

In physics, we are taught that longer wavelength (lower frequency) have a lower attenuation in air, and thus is able to travel longer distances. However, when talking about radio channels, short wave (...
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3 answers
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Driving GPIO outputs with FPGA: How to guarantee outputs of pins are set at same time

I was recently asked a question by an interview. We were discussing a hypothetical device that needed to drive 8 GPIO outputs of the FPGA. I was asked how to reduce the influence of propagation delay ...
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3 votes
1 answer
692 views

I am unable to figure out how the answer to following question is 70ns

Here's the question: Each full adder has 2 AND gates 2 XOR and 1 OR gate so carry propagation delay for each full adder should be 80 ns by the data provided and as there are 4 full adders, so shouldn'...
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1 answer
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How does propagation relate to switching time of a circuit?

I have this circuit: I know how to measure the propagation delay between a certain input and output. In my homework, I am required to optimize the area of each transistor. One point that occurs to ...
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How will supply voltage affect propagation delay?

Here is my circuit: I want to measure the propagation delay between the input D and output Y. As I understand it, the higher the supply voltage VDD is, the faster the propagation is. When I measure ...
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2 votes
1 answer
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Hold time constraint equation

I am trying to understand the equation for hold time in the Digital Design and Computer Architecture book: https://www.sciencedirect.com/topics/computer-science/hold-time-constraint Hold time ...
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I need an explanation for the dereviation of a factor in the Two-Ray Model in Wikipedia

In the Two-Ray model, I wish to understand how the marked factor in the attached picture has been derived. source: https://en.wikipedia.org/wiki/Two-ray_ground-reflection_model Is this factor the E ...
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1 vote
2 answers
211 views

Do more logic gates in series mean more slowing of the output result?

I heard that every logic gate has a propagation delay in nano scale. As the digital signal propagates through the logic gates, the signal output result will have a delay. Even though the delay is so ...
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2 answers
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Glass of microwave oven

From a user who "doesn't know" anything about Maxwell's equations. How to explain simply the behavior of a transparent glass of a microwave oven? Lets the light pass ... but blocks the "...
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From delay to distance?

I need to estimate the distance of a link having only delay values. How can I do that? I need to estimate this distance for ethernet and optical fiber links. I thought of doing it using the ...
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1 vote
1 answer
62 views

Mismatch of requirements from JEDEC with recommendations Intel(Altera)

I am studying the workings of DDR memory, in particular the recommendations for PCB layout. One of the intel documents (Table 1–24; Page 70) has the following wording: "Propagation delay of clock ...
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Counting no. of clock cycles

This question was asked in GATE 2021. Here I am finding it difficult to "manage" propagation delay of XOR gate. Solving it using timing diagram takes a lot of time and rough space. Is there ...
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2 answers
257 views

Holes in RF shield, what frequencies can escape?

So this is part of a theoretical design problem that I've come across not too long ago, and still can't find a satisfactory answer for it. Assume a large (infinite) metal plane with a round hole in it ...
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How to imagine the mathematical expression in the waveguide?

Below we see an example expression for the E-field. It has three components: polarization of the field propagation direction standing wave pattern In the photo below of the field "L" has ...
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Daisy Chaining Shift Register Concerns and Fan-out Limits

I've been tasked with massivly expanding some GPIO of a microcontroller, and my inital thought was to chain a bunch of SN74HC595 and SN74HC597 shift registers, however to get the ammount that's ...
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Latching Priority Encoder, circuit works but I don't trust it

I added a schematic even though the question is actually too simple for it. The datasheets for the devices are likely to be more revealing. The circuit is super simple. I have a 74HC148 priority ...
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3 answers
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How to calculate measurement error in a voltage divider?

I'm trying to calculate the measurement uncertainty of the voltage represented by the ADC in +/- V or % of a voltage measured across R2 of a voltage divider. What would be the general way to tackle ...
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1 vote
1 answer
97 views

Delaying clock pulses without adding (much) extra circuitry (CMOS)

I have a counter (74HC193) counting up with Qn outputs being decoded by a demultiplexer (74HC138). My clock pulses (CP) are no less than 100 microseconds long and the interval between them is always ...
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Is RF propagation path loss symmetrical and independent of clutter location?

Scenario: Consider two measurement points, point one is about 3m above ground level within a cluster of buildings (such as within an office park), and point two is about 1km away with an elevation ...
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1 vote
1 answer
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Is there a reason IC in the DIP package seem to have a very high propagation delay and so a very limited admitted frequency?

I scrolled through Mouser and I noticed that when you search for ICs with very low propagation delays there are only IC avaible in packages quite hard to use for an hobbyst/noob like me with very ...
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1 vote
1 answer
263 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 ...
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1 answer
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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 ...
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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 ...
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2 votes
1 answer
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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 ...
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1 vote
2 answers
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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 ...
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2 votes
1 answer
210 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 ...
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8 votes
2 answers
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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 ...
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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 ...
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3 answers
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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 ...
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1 vote
0 answers
146 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 "...
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0 votes
1 answer
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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 ...
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1 answer
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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 ...
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3 votes
3 answers
740 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....
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0 answers
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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
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0 votes
1 answer
390 views

Adder propagation delay

I want to compare the performance of a 4-bit full adder vs a sequential (serial) adder with one D flip-flop. The two models are in the followig figures Combinational adder: Serial adder: Let's say ...
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14 votes
4 answers
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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 ...
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0 votes
2 answers
560 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 ...
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2 votes
1 answer
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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 -...
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4 votes
1 answer
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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 ...
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2 answers
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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 ...
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-5 votes
1 answer
54 views

wave propagation ( pict) [closed]

Can someone explain to me what is a meaning of the starred items in this picture?
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1 vote
1 answer
405 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 ...
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1 vote
1 answer
56 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 ...
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1 vote
1 answer
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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 ...
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1 vote
2 answers
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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 ...
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-3 votes
1 answer
2k views

calculating propagation delay

We assume that every gate's delay is (microsecond). what is total propagation delay?
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2 answers
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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 (...
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