Questions tagged [characteristic-impedance]
Characteristic impedance is the ratio of the amplitudes of voltage and current of a single wave propagating along a transmission line (i.e. without reflections traveling in the other direction). Its SI unit is the ohm.
143 questions
0
votes
2
answers
136
views
How does pouring power copper around signals in a signal layer affect impedance?
I'm designing a PCB with a bunch of controlled-impedance differential pairs. I've determined that I must go to an 8-layer board. I'd like to use one of these Hartley-recommended stackups:
(Image ...
0
votes
3
answers
185
views
Why does Reflection Coefficient depend characteristic impedance that isn't there?
In this system, (Z_0) is the impedance used to measure the amplifier’s S-parameters. When measured, both the source and load impedances were set to (Z_0), typically using a vector network analyzer.
...
- 9
0
votes
0
answers
87
views
Electromagnetics - Impedance matching with a Double stub tuner
This is an example from the book "Electromagnetic field theory- A problem solving approach" by Markus Zahn. The book doesn't explain how the lengths \$l_1\$ and \$l_2\$ are calculated. My ...
- 1,313
0
votes
2
answers
218
views
Why don't PCB trace width calculation tools have an option for setting the currect capacity? Kicad tool as an example
I am using the Kicad trace width calculator tool for finding the width required for a 50 ohm trace.
The obtained value of trace width is 0.355mm. Assume this trace width is not enough for the ...
- 3,979
0
votes
2
answers
215
views
How can I build an impedance measurement circuit?
I am a PhD student and completely new to circuit design. I need a compact-sized circuit and prefer not to use an impedance analyzer due to its bulkiness.
I am looking to build a circuit capable of ...
0
votes
1
answer
70
views
Is it possible to bound the characteristic impedance of a connector pin if it's not impedance-controlled?
I'm currently assessing whether I need a feedthrough connector to be impedance controlled since it carries gigabit ethernet, but only after about 6 meters of cable. So I've made a LTSpice model with ...
- 9,917
0
votes
1
answer
174
views
PCB trace impedance infinite equivalent impedance of RLC model
I am trying to understand the PCB trace impedance model. Although not exactly, if we take a very small section of a PCB trace as an example, let's assume that it is in the form of series R, series L ...
- 824
1
vote
3
answers
407
views
How to match multiple impedance discontinuities?
I am trying to design a circuit to transmit various digital high frequency signals over cables, connectors and pcb to an oscilloscope. The simplified circuit looks like this:
simulate this circuit &...
- 49
1
vote
0
answers
337
views
coplanar waveguide impedance calculation and tolerance
The Ublox Sara R5 System Integration Guide I am following states that a 50 Ohm antenna waveguide design is recommended and provides a couple example designs that achieve this using FR4 dielectric.
...
- 517
0
votes
1
answer
105
views
PCB interconnect trace characteristic impedance (Z0) at low frequencies
In high frequency signals, we generally set the trace characteristic impedance between 50-120 Ω. Calculation tools, for example, use the impedance calculation tool designed by Altium Simbeor, and it ...
- 824
0
votes
2
answers
157
views
PCB trace impedances of integrated circuits with high input impedance
There is an ADC front end IC (opamp) at the input of my ADC card and it has high input impedance,
What should I set the differential trace impedance to when drawing the PCB? Does this matter much?
- 824
0
votes
2
answers
473
views
CAN Protocol traced routed with 90 ohm characteristic impedance
I am using ISO1042BDWV in my board. The schematic is given below. I know that the characteristic impedance of the CAN bus is 120 ohm.
The layout team routed CANH and CANL as 90 Ω differential. The CAN ...
- 3,979
7
votes
4
answers
923
views
Characteristic impedance of a BNC jack to jack adapter
I have this BNC jack to jack adapter. I want to measure its impedance but I am reading around 1mΩ. The datasheet says that it is a 50Ω adapter.
Why am I measuring such a low resistance?
- 324
0
votes
1
answer
102
views
Coax cables, impedance matching and BNC extensions
I'm trying to understand how to do proper measurements with a Voltage Differential Probe ( TT-SI 9010. This probe has an output impedance of 50ohm and has a BNC (It doesn't specify it in the data ...
- 324
0
votes
2
answers
438
views
Balun converting 100ohm single-ended trace to 50ohm single ended for spectrum analyzer
On my board, I have 100ohm differential pair traces connected to a 1:1 balun, so the signal impedance becomes 100ohm single ended. I would like to measure the signal spectrum with spectrum analyzer. ...
- 735