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Questions tagged [coupling]

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0answers
26 views

Load modulation vs load modulation with subcarrier

With two inductively coupled coils, load modulation is used to transmit information from a receiving coil to a transmitting coil. Why is load modulation with subcarrier far more common than regular ...
0
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1answer
55 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 ...
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1answer
53 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 ...
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1answer
63 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
63 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 ...
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0answers
23 views

What happens to the back emf of a coil if the load of another coil in the vicinity is changed?

Lets say I have two inductively coupled coils. Coil 2 has a resistive load which can be switched on and off at will. Coil 1 is connected to an AC voltage source. The magnetic field of coil 1 induces ...
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3answers
80 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
86 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 ...
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1answer
45 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
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2answers
120 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
27 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
69 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 ...
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1answer
42 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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3answers
314 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
91 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
94 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
115 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
226 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
49 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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0answers
212 views

Coupling two audio stages - Audio Switch and Audio Processor

I am designing a 5.1 channel amplifier with 2ch to 6ch up-mixing. I chose PT2323 as the 2ch to 6ch converter and PT2322 as the audio processor. The application circuit for the both ICs suggest that a ...
0
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1answer
81 views

AC coupling to ground in amplifer circuits

I have been told that this schematic will lead to a slow charging of C1 (on right) due to the flow of current from the rails of the opamp trickling into the signal line and slowly charging the ...
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0answers
29 views

On AC coupling DMM , does the DC part of the signal make a normal mode signal?

Suppose I want to measure the AC part of a signal using a AC coupling multimeter. Does the DC part of it (mean value) turn to be a normal mode signal?. Should a Normal mode be include in an error ...
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3answers
112 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
55 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
355 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 ...
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2answers
653 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
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2answers
50 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 ...
1
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1answer
232 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
245 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 ...
0
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0answers
71 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&-\...
0
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0answers
59 views

Question about inductive coupling equivalent circuit

Currently I am reading this http://www.rrc-wireless-power.com/fileadmin/website_wireless_power/Dokumente/Whitepapers/RRC_WirelessPower_Kontaktlose_Energieuebertragung.pdf paper about resonant ...
0
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3answers
66 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
100 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 ...
0
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1answer
64 views

48V coupling into digital signal

I have a large thruster that requires 48V to operate, which I've provided through an isolated supply (Vicor DC/DC isolated converters). The thruster uses a Hall-effect sensor to adjust the speed (-5V ...
6
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4answers
2k views

Why is a resistor added after the DC blocking capacitor of the op-amp input? [duplicate]

I read somewhere that the addition of R2 provides the DC return to ground however this would reduce the overall input impedance of the op-amp. Input impedance must be high for an op-amp. How to solve ...
2
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1answer
75 views

Which one of these shielded scenarios is correct?

I have a system were both the signal generated and the sensing equipment is sharing the same ground. Which one of these shield terminations scenarios is correct? (if any). I searched the internet for ...
0
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2answers
39 views

Coupling servo-motors [closed]

My application is a small robot-ic head - lets say for a scarecrow. It is going to be moved around frequently, during operation too. I obtained a lot of these "hobby" servos that are used in RC ...
8
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2answers
811 views

Need help reverse engineering and understanding a small circuit

I am an electronic student, and one day I opened an energy meter I have at home called EM21, and found out that its body is comprised of two major components: The meter body, that connects to the ...
1
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3answers
115 views

a standard method for flowing down EMC/EMI requirements to internal modules

EMC/EMI standards (conducted/radiated emission/susceptibility) are well established for system boxes. However there appears to be no standards, nor methods for deriving a specification for internal ...
0
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1answer
413 views

Adding a DC bias to an AC signal for amplification and measurement

I am trying to add a DC bias to this AC signal, but for some reason the schematics I found online for this do not work. The AC coupling is not happening. I have simulated the circuit here: http://...
0
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1answer
231 views

Two solenoid coils and ferrite rod, how to calculate mutual inductance or coupling co-eff

I have two solenoid coils, one is wounded on ferrite rod and other is wounded in larger diameter in proxmity of ferrite rod, see picture. It is used as wireless comm (simplex) between RX and TX where ...
0
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3answers
90 views

Do wires need to share similar characteristics in order for crosstalk to occur?

My understanding of crosstalk is how a radio transceiver works. You basically tune your transmitter and receiver to a similar frequency in order to get a cross-coupling of energy (the transmitter's ...
0
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1answer
79 views

coils/Inductors in series for power transfer

I have an air core inductor that I want to use for resonant coupling purposes. This inductor has an inductance value of 500nH. Is it ok to connect another inductor with a value of 100uH in series with ...
2
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1answer
501 views

Marvell PHY to KS8999 PHY connection

I'm trying to design a custom board with Marvell 88E1111 PHY and I want to connect this board to another board with KS8999 PHY on it. I want to connect two phy sides with capacitive coupling. The ...
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0answers
82 views

Peak value of sine wave for capacitively coupled inverting amplifier

I was working on question 2.23(a) and there is asked what input voltage is needed in order to ensure that the output does not clip. The clipping limits are +10 to -10 V. I solved that, and, ...
1
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1answer
118 views

Magnetic coupling between two coils for audio amplifier

I have a function generator that will emit an audio tone. I have two coils of wire and I'm trying to couple the audio signal from the primary coil to the secondary coil. The output of the secondary ...
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1answer
91 views

Electromagnetic coupling between two coils

I'm trying to understand the behaviour of electromagnetic coupling between two coils. One of my coils is connected to the output of a Colpitts oscillator as shown below with the excited coil labelled ...
2
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3answers
285 views

How to generate crosstalk between 2 wires?

I'm trying to recreate a situation where crosstalk is occurring. I'm having a bit of trouble trying to inductively cross couple two parallel wires that don't have any shielding or insulation and aren'...
3
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2answers
1k views

Ethernet Trace Layout with PoE & Integrated Magnetics

I'm a hobbiest & I've put together a simple PoE board using a LinkIt Smart Duo, the AG9050-2BR and a Bel Fuse 0813-1X1T-57-F. The power circuit works but the Ethernet signal wont work. The ...
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2answers
826 views

Single supply op-amp voltage follower - negative clipping with AC-coupled load

I am using a µC running DDS algorithm to synthesize certain waveforms (in fact I made 3 channel music generator with portamento&ampltude modulation effects, commands for changing waveforms etc. ...