Topics

067-0525-01 or equivalent needed.


 

Hi Eric,
As several people have pointed out already, the 1MHz bandwidth of the 7A22 Differential Amplifier is too low to require a T-cable matched to 0.1".

However, it occurred to me that you may have confused the 7A22 with the 7A13 Differential Amplifier. The 7A13 bandwidth is 100+MHz and it definitely does require a T-cable like the 067-0525 to test and adjust the plugin's high frequency common mode response.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Eric
Sent: Wednesday, November 11, 2020 12:01 PM
To: TekScopes@groups.io
Subject: [TekScopes] 067-0525-01 or equivalent needed.

I need this calibration fixture or something like it to calibrate a 7A22 and some 400 series scopes. This fixture is a BNC Y cable the important part is the Y side of the cable is matched length to within 0.1 inch. This is to remove cable aberrations and phase difference to the inputs. I don’t necessarily need the 067-0525 if I can order a matched length Y cable from somewhere.




--
Dennis Tillman W7pF
TekScopes Moderator


Gif Sim
 

thanks Raymond

I'm no longer in the lab
from the latest tests
I zoomed in and with the cursors I read a difference of about 28 ps
tomorrow I will try to slightly vary the length of one of the lines
to see what happens
this scope is a tds754D upgraded (with resistors and capacitors) to tds784D .... now it is with original calibration data of the 754D at 500 Mhz ..... it must do the full calibration at 1024 mhz of the 784d ..... .
these days I'm having fun calibrating a 754A upgraded to 784A

a big greeting
Simon


 

On Thu, Nov 12, 2020 at 11:13 PM, gifsim wrote:


I zoomed in and with the cursors I read a difference of about 28 ps
tomorrow I will try to slightly vary the length of one of the lines
to see what happens
Experimenting with a line length difference of between 0.2" and 0.4" will probably allow you to either double or halve the skew of 28 .. 40 ps.
Have fun calibrating your 784A!

Raymond


 

On Fri, Nov 13, 2020 at 12:07 AM, Raymond Domp Frank wrote:


Experimenting with a line length difference of between 0.2" and 0.4" will
probably allow you to either double or halve the skew of 28 .. 40 ps.
Loosening the bayonet and slightly pulling the plug out will have a visible effect.

Raymond


SCMenasian
 

4 GR874 to BNC adapters could be connected (in 2 pairs) to create two variable length lines. The 874 engagement can be adjusted slightly to create the desired delay.


Jean-Paul
 

We use a good quality BNC T and a pair of Tektronix precision 50 ohm 0.5 m cables, the type specific to SG503.

A 2-10X wideband passif attenuator like Mini Circuits HAT series can reduce abberations due to VSWR and reflection.

Jon


Eric
 

I have some high quality T's on order so I will be able to get this done. Thanks for all the advice.

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Dennis Tillman W7pF
Sent: Thursday, November 12, 2020 4:49 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 067-0525-01 or equivalent needed.

Hi Eric,
As several people have pointed out already, the 1MHz bandwidth of the 7A22 Differential Amplifier is too low to require a T-cable matched to 0.1".

However, it occurred to me that you may have confused the 7A22 with the 7A13 Differential Amplifier. The 7A13 bandwidth is 100+MHz and it definitely does require a T-cable like the 067-0525 to test and adjust the plugin's high frequency common mode response.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Eric
Sent: Wednesday, November 11, 2020 12:01 PM
To: TekScopes@groups.io
Subject: [TekScopes] 067-0525-01 or equivalent needed.

I need this calibration fixture or something like it to calibrate a 7A22 and some 400 series scopes. This fixture is a BNC Y cable the important part is the Y side of the cable is matched length to within 0.1 inch. This is to remove cable aberrations and phase difference to the inputs. I don’t necessarily need the 067-0525 if I can order a matched length Y cable from somewhere.




--
Dennis Tillman W7pF
TekScopes Moderator