Questions tagged [coupling]
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117
questions
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Finding effective mutual inductance between a parallel inductors and a separate inductor
The effective inductance of two parallel coupled inductors can be calculated as
\$ L_{eff} =\frac{ L_{1}L_{2} - M_{12}^2}{L_{1} + L_{2} - 2M_{12}} \$
where \$L_{eff}\$ is the effective inductance ...
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1answer
40 views
Coupling coefficient of microstrip resonators
I am working in HFSS and I'm trying to determine the coupling coefficient between two microstrip resonators (k) so that I can design a filter using a certain resonator shape. I have the formula I need....
1
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2answers
59 views
Unintentional capacitive coupling
This question comes from text from the AOE 3rd ed. It's about unintentional capacitive coupling right after differentiators in chapter 1. I've included the text. Please read the first excerpt. That is ...
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1answer
24 views
Does DiSEqC require a DC bias?
The DiSEqC (Di[gital] S[attelite] Eq[uipment] C[ontrol] specification (bus_spec.pdf within https://www.eutelsat.com/files/PDF/DiSEqC-documentation.zip) describes a tone-based serial data bus that can ...
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0answers
14 views
Deriving equations for coupled line transmission line for even-odd modes
Is V2e = V1e ， V2o = V1o ？
If not, how would we arrive at equations relating {V2e, V2o} to {V1e, V1o} respectively ?
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3answers
103 views
Shifting level voltage of a signal
I have a signal, which can vary from 400 to 7000 Hz approximately. It is a kind of pwm signal and has the time of high level, Ton, 30 times longer than the time of low level, Toff. The shape of the ...
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3answers
76 views
Adding small AC signal to a DC current using inductive coupling
Is it possible to add a small AC current on to a DC current in a wire using inductive coupling from an external source. Or if there is another way, I want to add AC ripples to a DC current.
simulate ...
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1answer
54 views
What grounding should I use for this capacitively coupled input?
I'm designing a device that will receive and digitize analog video signals. In analog video, it's recommended to capacitively couple inputs. A typical input might look like this:
In this case the ...
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1answer
97 views
2n7000 used for inductively coupled load modulation apparently latched
So I've got a fairly basic circuit set up for load modulation of an inductively coupled circuit:
A few notes on the above: LC's were designed for 1 MHz but work better at 950 kHz, thus the chosen ...
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0answers
30 views
How to find Q of a quarter-wave resonator loaded with a coupled-line coupler
I have a quarter wave resonator at frequency \$f_0\$ and characteristic impedance \$Z_{res}\$, which is coupled to a 50 Ohm load via a segment of coupled-lines coupler whose electrical length is \$\...
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4answers
129 views
AC-Coupling on Composite video
Many sources say that composite video input should be AC-coupled. Voltage levels for blank, black and white signal are also specified. How is it possible to detect these voltage levels after AC ...
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3answers
75 views
If a PEC surface completely reflects an EM wave, why doesn't an ungrounded shield work?
I was thinking about shielding and its effectiveness.
An ungrounded shield doesn't work well for either inductive or capacitive coupling.
However, if you think about plane wave theory, a PEC surface ...
0
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1answer
167 views
Coupling PCB traces
In my pcb design I have 2 triangular voltage signals with the following specs:
Peak voltage = 300V
Rise and fall time= 7us
Freq=25kHz
(assume a constant current of 0.5A)
Because of the limited ...
0
votes
1answer
80 views
Could shielding (not grounded) affect signal integrity?
I'm trying to shield 6 flat cables that give me some communication issues because I thought that there might be cross-talk or other sources of interference that cause the problem.
The shielding is ...
3
votes
2answers
188 views
How does placing cap between signal GND and earth GND solve common mode noise?
Thanks in advance for your time.
I am reading several articles about differential mode noise and common mode noise. Among which I found the below 2 pretty instructive:
https://www.murata.com/~/media/...
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0answers
51 views
Maximum ringing due to inductive coupling
Consider a bundle of wires carrying binary data and the worst case (or almost-worst case) scenario of them switching all at the same time. The wires with their partial mutual inductances would be ...
0
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2answers
128 views
Parallel inductive coupling approximation - coupling coefficient
I have the problem of a few independent current loops (wires) that on a portion of the circuit are close to one another so there will be inductive coupling between them.
Each wire, on the portion of ...
0
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1answer
90 views
Crosstalk between AC and DC
First time asking a question but I've come across something I just can't find the answer to. Whether or not it's because a silly question I hope to find out.
So I understand that with crosstalk ...
0
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3answers
196 views
How do I terminate a directional coupler?
I'm using a directional coupler for a radar application using frequencies of 5.3-5.9GHz. The directional coupler linked above is matched to a 50ohm characteristic impedance.
How do I terminate the ...
2
votes
1answer
87 views
Coupling coefficient variation in Wireless power transfer
Question regarding WPT compensation topologies.
I'm trying to make a inductive wireless power transfer system where the RX coil can move quite conisderably relative to TX coil and still transfer ...
0
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3answers
157 views
Why does the voltage induced in the receiver coil of this WPT circuit decrease when a load is added (in parallel)?
The following is a circuit that wirelessly transfers power via inductive coupling. The circuit is supposed to power a 12 V 0.15 A DC fan and a typical smartphone, which requires 5 V DC across it. The ...
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2answers
916 views
Mutual inductance vs coupling coefficient
Question regarding this and this question about mutual inductance and coupling coefficient.
I'm trying to analyse a two coil system:
It consists of two coils like in the picture with 2 cm air gap ...
0
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2answers
62 views
Is wireless technology only possible due to inductance?
I asked a friend how capacitative coupling works in glass-mount antennas.
He said it's like when installing a sound system; where you want to keep the power & audio cables separated, to avoid ...
0
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1answer
331 views
USB 3.1 AC Coupling Capacitor Implementation
How should the AC coupling should be implemented when connecting a USB 3.1 hub to a USB Type-C connector through a MUX. Is it:
Both sides of each MUX.
On the switched output of each MUX.
On the ...
0
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1answer
54 views
Why are inductively coupled RFID systems put in certain frequency bands when there are no EM waves used?
LF - 125 kHz
HF - 13.56 MHz
Those frequencies refer to the magnetic field that is used to induce a voltage in the transponder. Can the magnetic fields actually interfere with EM waves in the ...
0
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1answer
176 views
Help with design a mic preamp with opamps for PGA and ADC
I want to sample an audio source using an electret microphone and analyze the spectrum of it with a uC. I'm interested in the 100Hz-2.5kHz range, so I calculate with these values when I tried to ...
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3answers
94 views
RFID: Why is inductive coupling used instead of EM waves for LF and HF systems?
Is it because of antenna sizes? At 900 MHz a 1/2 dipole has a size of around 15 cm. That would be far higher for 125 kHz, so instead we use coils to power the transponder and use load modulation for ...
0
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3answers
505 views
AC coupling capacitor in the ground to break the ground loop?
I'm implementing the following audio single-ended to differential converter for an ADC:
This is the reference design for the PCM1804 that I intend to use.
What would happen if I do this:
Would it ...
0
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1answer
123 views
Can someone explain how frequency and inductance affects this pair of coupled inductors?
I am simulating this simple circuit on PSIM; a single-phase AC voltage source connected to the primary of a pair of coupled inductors, with a 12 Ohms load on the secondary side. I want to increase the ...
0
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1answer
51 views
Capacitive coupling: how to collect 60uA from this set-up?
I need to collect at least 60uA via capacitive coupling between a high tension Cu cable with PVC insulation and a connector that is acting as the opposite face of the capacitor (can be a copper plate ...
3
votes
2answers
348 views
How do coupling capacitors in transistor not affect biasing?
I understand the usefulness of the capacitors in an amplifier circuit but i dont understand why we use one at the input? and how does this not affect the biasing if it removes the dc voltage?
Thanks.
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1answer
234 views
Series and Parallel RLC Circuit [closed]
I am trying to build a resonant circuit for data communication between coils.
Which would be better, a series or a parallel resonant circuit?
What is the difference between them and in which ...
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2answers
87 views
Is this phenomenon capacitive coupling or human antenna effect?
I injected a 90 MHz signal into an electrical cable via a signal generator. And I used a spectrum analyzer to measure the signal strength of 90 MHz at the other end of the cable. Then I found the ...
0
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1answer
69 views
Coupling between a cable and the main power line: how to measure it?
I'm wondering what's the simplest way to find the value of capacitive coupling between a cable and the main power line (230Vrms @50Hz, I'm in Europe) to use afterwards in some SPICE simulations. I ...
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vote
3answers
667 views
Shock from Capacitive Coupling
In an AC supply which is not earth grounded, I see a small amount of current flowing to ground from both wires of the supply (live wire has higher) even though the circuit is incomplete.
It is due ...
0
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3answers
329 views
How to find coupling and decoupling capacitor values?
I am trying to learn receiver design, one thing I noticed is the use of coupling capacitors and decoupling capacitors and incuctors. There were set of standard values such as 100 pF, 1000 pF or 0.1 uF ...
2
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2answers
217 views
Crosstalk in analog switch
Art of Electronics, 3rd Ed, pg. 179, gives a model for the capacitive coupling between independent channels of an AD7510DI analog switch. The authors ask to calculate the coupling between channels ...
0
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1answer
378 views
SPICE modelling output/input coupling in ultrasonic transducer driver
The real device is this.
The LT SPICE model is here.
The schematic of the driver part of the circuitry (omitting power supply circuitry and relay circuitry that basically switches the driver between ...
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3answers
1k views
What does an RF coupler actually do?
I've spent a few hours reading about the basics of RF directional couplers, but I am still having trouble understanding just the very basics of what a coupler does. To start with, I've had difficulty ...
0
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1answer
79 views
Op-amp for audio-arduino interfacing circuit
Is it possible to use opamp of LM392 in this circuit for interfacing audio to Arduino? I had LM392 laying around so I tried it, but it doesn't work, the output is always exactly 2.50V. I am not sure ...
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3answers
437 views
Superimpose a High Frequency AC Small Signal on a DC Power Signal
I am facing a challenging problem with a circuit that I am currently working on, I would like others input and thoughts.
I have a DC power signal that I am injecting a AC small signal this mixed ...
0
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1answer
62 views
Input biasing and coupling calculations
I have a low frequency input signal 3-80 Hz that I am feeding into an inverting op-amp input. I am slightly confused as to what values I should choose for the following components - R3, C2, R4:
The ...
0
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1answer
516 views
DC and AC coupling peak-peak difference
I have been measuring signals in an oscilloscope and I have stumbled upon a practical exercise of calculating the DC offset of a signal. Basically what I did was turn on the DC coupling, take the ...
3
votes
2answers
900 views
Oscilloscope AC coupling and PWM signal
I made a traditional PWM signal generator using a 555 timer IC.
However, when I connect the output (pin 3 of the 555) to my oscilloscope and set it to AC coupling, the signal shown on the display is ...
3
votes
2answers
66 views
Ensuring certain amplitude level of RF signal on a PCB board
I have an RFIC which has an LO input. This LO input has rails 0V and 1V and the LO input should be rail-to-rail. The termination is on-chip and may not be perfect.
The LO comes from an off-board 90 ...
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1answer
463 views
Choosing capacitor for RF coupling
I want to couple 10W at 150MHz, 50 Ohms (before and after an RF switch). The PA is a RA08H1317M powered by 14V DC.
How do I choose an RF coupling capacitor?
I have found this answer, but it only ...
1
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1answer
347 views
Some questions about a magnetically coupled circuit
Below the RLC circuit on the left side by the help of a periodic impulse generator V1 generates periodic damped oscillations with a certain frequency, and the resulting oscillating current couples to ...
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0answers
181 views
Two cascade directional couplers
I have the following question regarding directional couplers. Below is the question.
My solution was to multiply the scattering matrices of both couplers as in the following
\begin{pmatrix}0&-\...
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3answers
193 views
Properties of an Ideal Transformer and the reasons behind them
Why should the magnetising reactance of an ideal transformer be very large i.e. approach infinity? What practicality does this imply?
0
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1answer
198 views
Power Line Communication
I am using an emitter and a receiver circuit in order to communicate through the power line.
The receiver circuit I am using is shown at the figure below and it uses the LM567 tone decoder to decode ...
