All Questions
Tagged with impedance-matching input-impedance
19
questions
0
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0
answers
93
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RF amplifier class A
I have simulated a class A RF amplifier. When I simulated the output impedance, it is around 50 Ω for the frequency range that is of interest (50 kHz to 100 MHz), now at the input impedance is around ...
- 536
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votes
1
answer
63
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Weired result of Ltspice Zin measurement, Phase shift of -104°
I am trying to measure the input impedance of this amplifier to design a matching network for it. But the input impedance I get has a phase of -104° at the frequency of interest. I thought that Phase ...
- 127
2
votes
1
answer
113
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Why do LDMOS RF power transistors have a low real resistance?
I've been looking through datasheets for RF LDMOS amplifiers for use in an RF power amplifier. They typically have an input impedance that has some small real part of the resistance (<10 Ω) with a ...
- 513
2
votes
1
answer
95
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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
1
vote
2
answers
186
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Are frontend amplifiers in RF transceivers impedance matched?
I think by now I get complex impedance, the Smith chart, and antenna matching, but I am wondering how in an RF transceiver, i.e. a radio, the amplifiers on the transmitting and the receiving end are ...
- 173
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134
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S-Parameters Power amplifier impedance matching
I recently decided to conceive a 10W class 446MHz amplifier.
I want to be able to amplify a 100mW signal into a 10W, for that i'm going for a two stages amplifier :
SKY65162 to amplify the signal to ...
0
votes
1
answer
86
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Impedance sensing technology with headphone extension cord [closed]
I have a simple question and I've tried researching the topic but I don't understand the technology. My computer uses impedance sensing technology to set the impedance for headphones. My situation is ...
- 101
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0
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362
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What is Input Impedance Mismatching of differential Operational Amplifier?
I am new to design differential op-amp.
I am not sure if my circuit will experience input impedance mismatching.
Can anyone explain how input impedance mismatching will happen in differential op-amp? ...
3
votes
2
answers
1k
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How do you match an LDMOS FET to 50 Ohms?
I'm considering using one of the following LDMOS FETs as an RF amplifier:
AFM907N (8W)
AFT05MS031NR1 (30W)
AFT05MP075NR1 (70W)
The datasheets provide \$Z_{source}\$ and \$Z_{load}\$ metrics for some ...
- 2,190
2
votes
1
answer
3k
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Input/Output Impedance of DC/DC converters and Impedance matching
I am interested in understanding how do DC/DC converters achieve impedance matching for maximum power transfer applications. After visiting this (historical) entry, you can see in the "impedance ...
- 391
0
votes
2
answers
913
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Measurement of s11 with reduced power on NanoVNA
I am developing a 10.7 MHz IF amplifier for a radio receiver. In order to match the input to the output of the driving mixer stage (330 ohm) I need to measure the input impedance.
I did the ...
- 885
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votes
3
answers
358
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What does a simple passive circuit to simulate an impedance mismatch look like?
I am trying to learn some of the basics of circuit design. One thing I am curious to make a filter/schematic of is what happens when a voltage source hits an impedance mismatch.
eg. A high impedance ...
- 157
1
vote
2
answers
381
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maximum power transfer explanation
Please provide an intuitive explanation of maximum power transfer.
This is a conceptual question therefore I want to ask with an example. I'm wondering in which cases impedance matching is used.
For ...
- 17
-1
votes
1
answer
386
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Removing the imaginary part of input impedance of a Monopole in HFSS
I am building a Monopole in HFSS for my project. Its structure is shown here :
The input impedance at the desired frequency is :
Now i need to eliminate the imaginary part , so that the voltage and ...
- 23
-1
votes
4
answers
575
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Op-amp ideal characteristics
In a textbook, it says that the ideal op-amp should exhibit following electrical characteristics and one of them is - **
Infinite input resistance (R) so that almost any signal source can
drive ...
- 339