All Questions
Tagged with impedance-matching transmission-line
71
questions
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Why does my calculation for transmission line reflection and transmission at a load have infinite solutions?
Take a transmission line with some characteristic impedance and insert a load somewhere along the line. What are the transmitted and reflected signals, given an sinusoidal input. Physically this ...
- 343
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S21 calculation
In this post
It mentioned that there's a factor 2 in S21 value.
But I'm still don't understand why there's a 2 in it.
My schematic is shown below.
Shouldn't S21 = Vout/Vgen?
My question is: where is ...
- 141
1
vote
1
answer
52
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Coax cables and input impedances
I'm doing a voltage measurement with the help of an Active Differential Probe (TESTEC TT-SI 9010) with an output voltage of +-7V. This voltages have rise times of the order 500ns.
The set up looks ...
- 324
1
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Intuitive explanation of shorted stub behaviour
Can someone please give me an intuitive explanation of shorted stub behaviour?
NOTE: This is not a duplicate of Intuitive explanation of open stub behaviour which has been narrowed to focus on open ...
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2
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Intuitive explanation of open stub behaviour
Can someone please give me an intuitive explanation of open stubs?
I have the length-based mathematical derivation and explanation from my textbook, but I am looking for an intuitive one.
For example,...
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1
answer
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Ultrasound System Design: Navigating Transmission Line Challenges and Impedance Matching
Hello community!
I'm currently working on the design of an ultrasound scanning system, and I'm seeking guidance, particularly in the realm of high frequency PCB design and transmission lines.
My ...
- 173
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2
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118
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Matching network for a radio
I’m trying to understand how the matching network functions on the radio side of a transmission line. As an example, here’s an excerpt from the Nordic nRF52840 DK schematics.
As I understand it, when ...
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4
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Impedance matching, don't reflections just happen somewhere else?
I understand that when I have a line transmitting a signal, it may be important depending on the length of the line and the wavelength of the signal to have matching impedances at the ends of the line ...
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Transmission line max power transfer
I'm studying transmission lines and came up with the question why (voltage) reflection coefficient being zero is not equal to maximum power transfer (conjugate matching). I did some search and found ...
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Why does the normalized input admittance have to be 1 +j0 to achieve matched condition at MM'?
In section 2.11.1 in the book Fundamentals of Applied Electromagnets by Fawwaz T. Ulaby, it says that in order for the circuit below to be matched at MM', y-in must be y-in = 1+ j0. Why is this so? ...
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3
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745
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Cannot trigger digital logic because half of source voltage is lost in impedance matching
I am using a 3.3V output of an NI controller over a coax transmission line. I have matched the termination resistor to the 50 Ohm source resistance. I need to use this output signal to control three ...
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answer
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When should an unmatched antenna be measured with a cable length in even multiples of a half-wavelength?
A few years ago someone told me that if you use a cable which has a length of an even half-wavelength multiple for the frequency being tested, then the impedance measured at the end of that cable will ...
- 2,190
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1
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How can I match the impedances in this circuit?
I have a pre-amplifier with 93.1 Ω output impedance connected to a main amplifier with input impedance of 1000 Ω via 75 Ω co-axial cable.
The signals are very small pulses from a measurement device ...
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3
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5
answers
1k
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Impedance matching for short transmission lines
Why is it that impedance matching does not matter if the transmission line is shorter than the wavelenght of the signal?
Why do you get zero reflection if the line is shorter than the wavelenght?
Also,...
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3
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Effect of small length impedance discontinuity in a transmission line
Consider this arrangement of a radio, a long coax cable, a small length of "random" cable and an antenna. The radio, the coax and the antenna all have the same impedance, but the random ...
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