Impedence matching. - Page 2 - Electronic Circuits Projects Diagrams Free

David Bridgen · 4th June 2005, 12:15 AM

Quote:

Originally Posted by stevez

David - would you explain how the circuit works. This design is similar to others I've seen in ARRL and other publications. I trust that it (and other designs) does what you say it does but I don't understand how you separate the forward power and reflected.

Let's have your email address stevez.

lord loh. · 4th June 2005, 04:17 AM

Quote:

Originally Posted by David Bridgen

Let's have your email address stevez.

Let us all have the benifit of your expertise.

Please.

David Bridgen · 4th June 2005, 09:36 PM

I have put a brief description on the web page.

mahinda jayasinghe · 5th June 2005, 09:19 AM

SWR- we need impedence matching to transfer maximum power.

There is a very usefull meter working under this principal.
TDR-Time domain reflecto meter

It is used to locate damaged transmission lines.

EG: Coax cable or antenna cable.

Coax cable has a characteristic impedence EG, 50 Ohm , 75 Ohm etc.

Is thare any damage along the cable, the impedence is not equal to its ch impedence.
Connect a dummy load (50Ohm termination at the end of the cable)
If the TDR send 1V pulse, Load does not reflect any siganl back to the TDR. if the load is open , it reflect the 1V with the same phase,

If load is short circuited, it refelect the signal with opposit phase.
TDR screen shows in positive direction pulse(if open) or negative pulse(if short).

Whwn terminated with a matching dummy load, TDR screen display refkected pulses, and also distace can be calculated to where the damage is.

stevez · 6th June 2005, 11:46 AM

David - thanks for taking the time to add the explanation.

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4th June 2005, 09:36 PM	(permalink)
David Bridgen	I have put a brief description on the web page.

5th June 2005, 09:19 AM	(permalink)
mahinda jayasinghe	SWR- we need impedence matching to transfer maximum power. There is a very usefull meter working under this principal. TDR-Time domain reflecto meter It is used to locate damaged transmission lines. EG: Coax cable or antenna cable. Coax cable has a characteristic impedence EG, 50 Ohm , 75 Ohm etc. Is thare any damage along the cable, the impedence is not equal to its ch impedence. Connect a dummy load (50Ohm termination at the end of the cable) If the TDR send 1V pulse, Load does not reflect any siganl back to the TDR. if the load is open , it reflect the 1V with the same phase, If load is short circuited, it refelect the signal with opposit phase. TDR screen shows in positive direction pulse(if open) or negative pulse(if short). Whwn terminated with a matching dummy load, TDR screen display refkected pulses, and also distace can be calculated to where the damage is.

6th June 2005, 11:46 AM	(permalink)
stevez	David - thanks for taking the time to add the explanation. __________________ stevez