Comments on: TDR circuit kit available

By: uncategorized

uncategorized — Sat, 24 Aug 2019 04:35:57 +0000

When some one searches for his necessary thing, therefore he/she needs
to be available that in detail, therefore that thing is maintained over
here.

By: Tomi Engdahl

Tomi Engdahl — Mon, 22 Oct 2018 13:06:29 +0000

More expensive TDR instruments:

TDRs measure reflections to 10 GHz and 15 GHz
https://www.edn.com/electronics-products/other/4461144/TDRs-measure-reflections-to-10-GHz-and-15-GHz?utm_source=newsletter&utm_campaign=ad&utm_medium=EDNPCBDesign-20181022

Whenever you launch a high-frequency signal into a PCB trace, connector, or cable, you worry about signal integrity. Impedance mismatches cause reflections as a function of frequency, which degrade signals. Therefore, you need to measure how much of an incident signal will reflect to the source. While vector-network analyzers can measure S-parameters that characterize reflected energy, they can be overkill in some applications. That’s where a time-domain reflectometer (TDR) can fill the bill.

TDRs are often sold as extensions to oscilloscopes, but they can be separate instruments, That’s where the T3SP10D (10 GHz) and T3SP15D (15 GHz) TDRs from Teledyne LeCroy come in. The instruments connect to a PC, making them portable. Indeed, you can use them in the field because they can run on battery power. Teledyne LeCroy calls the TDRs “Teledyne Test Tools (T3),” the first instruments of the brand that will complement its oscilloscopes.

TDRs send a pulse to the target and measure the reflected signal, then calculate S11 (see S-Parameter Backgrounder), time-domain measurements (time of reflection), or produce Smith Charts based on the rise time of the pulse.

T3SP Time Domain Reflectometers
http://teledynelecroy.com/time-domain-reflectometers/default.aspx

By: Tomi Engdahl

Tomi Engdahl — Fri, 20 Jan 2017 08:31:39 +0000

Thank you for your feedback.

By the way what was the version of 74xx14 IC used in your design that run directly from 9V battery?
According to the datasheet ( http://cva.stanford.edu/classes/cs99s/datasheets/74AC14.pdf ) the recommended maximum supply voltage for 74AC14 is 6.0V and absolute maximum is said to be 7.0V. So running that IC at 9V would not sound right?

The same voltage range applies also to 74HCT14 and 74HC14 etc…

I am interested on what was used on circuit that runs from 9V battery without regulator.

By: Al Yelvington

Al Yelvington — Fri, 20 Jan 2017 01:31:10 +0000

I used an early version of this circuit when I was a Coast Guard field service tech. It was shared through a joint Navy and Coast Guard pub targeted at technicians, and it used a 9V battery without a regulator. The rise time was good, and it was great for shooting cables when I didn’t have my real Tektronix TDR with me. I’m going to see if I can update this design to surface mount parts, and bump up the output pulse amplitude.

By: Tomi Engdahl

Tomi Engdahl — Sat, 13 Jun 2015 06:14:59 +0000

The kit is supplied by http://www.farcircuits.net/ and they list it on their web site.
So order through from http://www.farcircuits.net/

The page says:
“Orders accepted only by surface mail or FAX. NO orders , or via e-mail. All orders are to be prepaid by check, money order, or PAYPAL. To order please indicate the ship to address, home phone number, quantity of boards, magazine article title, publication, issue date, and any other information that would be helpful in identifying the board.”

By: Jon

Jon — Fri, 12 Jun 2015 14:28:13 +0000

Is the TDR kit still available please and could you post to the UK? If so, what payment (PayPal?) do you accept? Thanks

By: tomi

tomi — Thu, 21 Nov 2013 19:57:14 +0000

You are right that my original circuit did not have 7805 regulator, because I powered it from 4.5V battery power (first 4.5V battery and later three 1.5V AA batteries).

If I remember right (long time ago so I am not completely sure), the kit I received had the regulator IC in it..

By: David

David — Thu, 21 Nov 2013 16:27:37 +0000

I just received my kit from Far Circuits. It contained everything except the 7805 regulator that is marked on the board. Dunno if this is simply because Tomi’s original didn’t use one, but it’s probably too much work to hassle Fred for the “missing” bit.

By: desherbeurs thermiques

desherbeurs thermiques — Sun, 20 Oct 2013 10:38:01 +0000

An intriguing discussion is definitely worth comment.
I do think that you need to publish more on this
topic, it might not be a taboo subject but typically
people do not speak about these subjects. To the next! All the best!!

By: tomi

tomi — Wed, 10 Apr 2013 07:31:06 +0000

You find the circuit details here:
Time Domain Reflectometer (TDR)
http://www.epanorama.net/circuits/tdr.html

Blog postings related to TDR circuit
http://www.epanorama.net/blog/2010/04/27/tdr-circuit-modification-idea/
http://www.epanorama.net/blog/2010/07/17/tdr-circuit-kit-available/
http://www.epanorama.net/blog/2010/09/29/tdr-kit-built/