S-parameter test sets

[Terry Given]

what is the most common impedance used with S-parameter test sets - 50
or 75 Ohms? my guess would be 50 Ohms, based on no knowledge whatsoever.

what would be the pros and cons of one vs the other?

I am looking at buying one for my 200MHz HP3577 network analyser

Cheers
Terry

 

[Wes Stewart]

On Wed, 22 Jun 2005 16:57:46 +1200, Terry Given <my_name@ieee.org>
wrote:

what is the most common impedance used with S-parameter test sets - 50
or 75 Ohms? my guess would be 50 Ohms, based on no knowledge whatsoever.

Most common would be 50. In the CATV biz I suppose it would be 75.

what would be the pros and cons of one vs the other?

Unless you're in the CATV (video) biz, there is no pro for 75.

I am looking at buying one for my 200MHz HP3577 network analyser

Wow, how did you acquire one of these? Before my retirement I had one
in "my" (Hughes) lab. I seldom used the s-parameter TS, since I also
had available an HP8510C. If I remember correctly (risky propostion
these days), the TS was not a true reversing one where all four
parameters could me measured with one connection. There certainly
wasn't enough trace memory for all four parameters, maybe that was the
limitation. Anyway IIRC you will need software to make full two-port
measurements.

Mine wound up being mostly used to characterize quartz crystals. I
wrote software (HP-Basic) that my friends tell me is still cranking
away. I made extensive use of the trace math capability of the
analyzer to limit the workload of the computer. (HP-9836 fully loaded
with a whopping 1M of RAM!)

Today in retirement, I'm content with my N2PK network analyzer.

www.n2pk.com

 

[Terry Given]

Wes Stewart wrote:

On Wed, 22 Jun 2005 16:57:46 +1200, Terry Given <my_name@ieee.org
wrote:


what is the most common impedance used with S-parameter test sets - 50
or 75 Ohms? my guess would be 50 Ohms, based on no knowledge whatsoever.


Most common would be 50. In the CATV biz I suppose it would be 75.

what would be the pros and cons of one vs the other?


Unless you're in the CATV (video) biz, there is no pro for 75.

thats kind of what I thought.

I am looking at buying one for my 200MHz HP3577 network analyser


Wow, how did you acquire one of these? Before my retirement I had one
in "my" (Hughes) lab. I seldom used the s-parameter TS, since I also
had available an HP8510C. If I remember correctly (risky propostion
these days), the TS was not a true reversing one where all four
parameters could me measured with one connection. There certainly
wasn't enough trace memory for all four parameters, maybe that was the
limitation. Anyway IIRC you will need software to make full two-port
measurements.

I saved for a while, then spent $2000.

Mine wound up being mostly used to characterize quartz crystals. I
wrote software (HP-Basic) that my friends tell me is still cranking
away. I made extensive use of the trace math capability of the
analyzer to limit the workload of the computer. (HP-9836 fully loaded
with a whopping 1M of RAM!)

The manuals havent arrived yet, but I am going to have to figure out how
to drive this puppy in some detail. Any knowledge you would like to
impart will be gratefully received (and archived).

Today in retirement, I'm content with my N2PK network analyzer.

www.n2pk.com

yeah, thats pretty neat. I thought about making one, but I want to do
control loop analysis (among other things) and so need phase too, but
not as much bandwidth - but 200MHz is still pretty useful

Cheers
Terry

 

[Mike Monett]

Terry Given wrote:

Wes Stewart wrote:

[...]

Today in retirement, I'm content with my N2PK network analyzer.

www.n2pk.com

yeah, thats pretty neat. I thought about making one, but I want to do
control loop analysis (among other things) and so need phase too, but
not as much bandwidth - but 200MHz is still pretty useful

Cheers
Terry

Terry,

Are you talking about a different unit? Here's the description for n2pk:

" capable of both transmission and reflection measurements from 0.05 to
60 MHz, with about 0.035 Hz frequency resolution and over 110 dB of
dynamic range. Its transmission measurement capabilities include
gain/loss magnitude, phase, and group delay. Its reflection measurement
capabilities include complex impedance & admittance, complex reflection
coefficient, VSWR, and return loss."

This is a neat system - fits on a 2.5" x 3.8" pcb, so it can't be that
difficult to build.

For low frequency work, it might be possible to extend the low frequency
limit by reducing the crystal frequency. However, oscillator jitter is
important. Read his article "Testing of the Fox JITO-2 Oscillator as the
N2PK VNA Master Oscillator":

http://users.adelphia.net/~n2pk/VNA/JitoPN.html

Mike Monett

 

[Terry Given]

Mike Monett wrote:

Terry Given wrote:

Wes Stewart wrote:


[...]


Today in retirement, I'm content with my N2PK network analyzer.

www.n2pk.com

yeah, thats pretty neat. I thought about making one, but I want to do
control loop analysis (among other things) and so need phase too, but
not as much bandwidth - but 200MHz is still pretty useful

Cheers
Terry


Terry,

Are you talking about a different unit? Here's the description for n2pk:

oops, yes I was. but I had seen the n2pk before.

" capable of both transmission and reflection measurements from 0.05 to
60 MHz, with about 0.035 Hz frequency resolution and over 110 dB of
dynamic range. Its transmission measurement capabilities include
gain/loss magnitude, phase, and group delay. Its reflection measurement
capabilities include complex impedance & admittance, complex reflection
coefficient, VSWR, and return loss."

This is a neat system - fits on a 2.5" x 3.8" pcb, so it can't be that
difficult to build.

nope. hard to beat opening a box though.

For low frequency work, it might be possible to extend the low frequency
limit by reducing the crystal frequency. However, oscillator jitter is
important. Read his article "Testing of the Fox JITO-2 Oscillator as the
N2PK VNA Master Oscillator":

its great stuff, I read and archived it a while back.

I really need to get below 50Hz for power supplies - eg PFC loops tend
to have closed loop bandwidths smaller than line frequency.

http://users.adelphia.net/~n2pk/VNA/JitoPN.html

Mike Monett

Cheers
Terry

 

[Mike Monett]

Terry Given wrote:

[...]

its great stuff, I read and archived it a while back.

I really need to get below 50Hz for power supplies - eg PFC loops tend
to have closed loop bandwidths smaller than line frequency.

Cheers
Terry

Yes, 50Hz might be slow. It might be worth looking at variable sampling
time. Longer sample time for low frequency data points, then speed it up
as the frequency gets higher.

The thing that appeals to me with this approach is you have complete
control over your destiny. If anything breaks, you can always fix it, or
redesign it as the technology improves.

Old test equipment might be inexpensive, but eventually you can't find
parts needed to repair it anymore. And it somehow finds a way to fail
just when you need it the most.

I just gave away a complete TEK 7854 system with many plugins that gave
excellent service for many years. It developed a fault in the display
system that I couldn't fix, and couldn't find a replacement card. Some of
the plugins were starting to go, so the handwriting was on the wall.

Mike Monett

 

[Joerg]

Hello Terry,

Wow, how did you acquire one of these? Before my retirement I had one
in "my" (Hughes) lab. I seldom used the s-parameter TS, since I also
had available an HP8510C. If I remember correctly (risky propostion
these days), the TS was not a true reversing one where all four
parameters could me measured with one connection. There certainly
wasn't enough trace memory for all four parameters, maybe that was the
limitation. Anyway IIRC you will need software to make full two-port
measurements.

I saved for a while, then spent $2000.

That is a very good price I think. It is a nice analyzer. The only
downside is that it won't function as a spectrum analyzer.

Regards, Joerg

http://www.analogconsultants.com

 

[Terry Given]

Joerg wrote:

Hello Terry,

Wow, how did you acquire one of these? Before my retirement I had one
in "my" (Hughes) lab. I seldom used the s-parameter TS, since I also
had available an HP8510C. If I remember correctly (risky propostion
these days), the TS was not a true reversing one where all four
parameters could me measured with one connection. There certainly
wasn't enough trace memory for all four parameters, maybe that was the
limitation. Anyway IIRC you will need software to make full two-port
measurements.


I saved for a while, then spent $2000.


That is a very good price I think. It is a nice analyzer. The only
downside is that it won't function as a spectrum analyzer.

Regards, Joerg

Hi Joerg,

I was pretty happy with it. I figured out your last point while reading
the 3577 datasheet, so I spent $1000 and bought an HP3585A 20Hz - 40MHz
speccy. Which I brought home at about 10pm on wednesday night. Then
spent until 7am thursday morning playing with it, before driving up to
auckland for a customer meeting *grin* - kid in a candy store.....

It was easy figuring out how to drive the speccy, but the NA is a bit
trickier. The manuals should be here soon though. I have wanted both of
these beasts for a *long* time. A place I worked at used to have a
couple of Venables - one frequency response analyser, and one Dean. Man
did I learn a lot.

Cheers
Terry

 

[Wes Stewart]

On Thu, 23 Jun 2005 05:58:51 +1200, Terry Given <my_name@ieee.org>
wrote:

[snip]

The manuals havent arrived yet, but I am going to have to figure out how
to drive this puppy in some detail. Any knowledge you would like to
impart will be gratefully received (and archived).

I do have something in my storage building. Not actual instrument
manuals, but some app note stuff. I'll dig it out and see if I can
scan it for you. I have only a 28.8K dial-up tho and big files are a
pain to send. Maybe I can break it into pieces.

I'll get back to you.

Wes

Today in retirement, I'm content with my N2PK network analyzer.

www.n2pk.com

yeah, thats pretty neat. I thought about making one, but I want to do
control loop analysis (among other things) and so need phase too, but
not as much bandwidth - but 200MHz is still pretty useful

Cheers
Terry

 

[Terry Given]

Wes Stewart wrote:

On Thu, 23 Jun 2005 05:58:51 +1200, Terry Given <my_name@ieee.org
wrote:

[snip]

The manuals havent arrived yet, but I am going to have to figure out how
to drive this puppy in some detail. Any knowledge you would like to
impart will be gratefully received (and archived).


I do have something in my storage building. Not actual instrument
manuals, but some app note stuff. I'll dig it out and see if I can
scan it for you. I have only a 28.8K dial-up tho and big files are a
pain to send. Maybe I can break it into pieces.

I'll get back to you.

Wes

I would really appreciate that, App notes are often where the gold
resides. I'd gladly pay you to burn it to a CD and mail it to me, if its
not too much trouble. I dont want to eat your bandwidth though.

Cheers
Terry

 

[Terry Given]

Wes Stewart wrote:

On Fri, 24 Jun 2005 05:24:15 -0700, Wes Stewart <n7ws_@*yahoo.com
wrote:



Terry,

This should get you started:

http://users.triconet.org/wesandlinda/3577_TOC_CH1.pdf

Wes

Yee-ha! Thanks Wes, thats fantastic! Nice car, too

Regards,
Terry Given

 

[Wes Stewart]

On Sat, 25 Jun 2005 01:48:40 +1200, Terry Given <my_name@ieee.org>
wrote:

Wes Stewart wrote:
On Fri, 24 Jun 2005 05:24:15 -0700, Wes Stewart <n7ws_@*yahoo.com
wrote:



Terry,

This should get you started:

http://users.triconet.org/wesandlinda/3577_TOC_CH1.pdf

Wes

Yee-ha! Thanks Wes, thats fantastic! Nice car, too

thanks,

I've got to run to some appointments but I'll try to get some more of
the doc posted later.


Wes

ps. I see I need to update my email address on my site. Direct it's
n7ws at yahoo.com

 

[Wes Stewart]

Terry,

Chapter 2.

http://users.triconet.org/wesandlinda/3577_CH2.pdf

Chapter 3.

http://users.triconet.org/wesandlinda/3577_CH3.pdf

Let me know when you've got this so I can delete it. I'm at my
storage limit.

Also, do you need the HP-IB codes at this time?

Wes

 

[Wes Stewart]

On Fri, 24 Jun 2005 23:52:09 +1200, Terry Given <my_name@ieee.org>
wrote:

Joerg wrote:
Hello Terry,

Wow, how did you acquire one of these? Before my retirement I had one
in "my" (Hughes) lab. I seldom used the s-parameter TS, since I also
had available an HP8510C. If I remember correctly (risky propostion
these days), the TS was not a true reversing one where all four
parameters could me measured with one connection. There certainly
wasn't enough trace memory for all four parameters, maybe that was the
limitation. Anyway IIRC you will need software to make full two-port
measurements.


I saved for a while, then spent $2000.


That is a very good price I think. It is a nice analyzer. The only
downside is that it won't function as a spectrum analyzer.

Regards, Joerg

Hi Joerg,

I was pretty happy with it. I figured out your last point while reading
the 3577 datasheet, so I spent $1000 and bought an HP3585A 20Hz - 40MHz
speccy.

I had one of those too in "my" lab. I would sure give a K-buck for
one. Where are you finding these deals?

Now you need an '8566B!

 

[Fred Bartoli]

"Terry Given" <my_name@ieee.org> a écrit dans le message de
news:KtSue.9967$U4.1309297@news.xtra.co.nz...

I was pretty happy with it. I figured out your last point while reading
the 3577 datasheet, so I spent $1000 and bought an HP3585A 20Hz - 40MHz
speccy. Which I brought home at about 10pm on wednesday night. Then
spent until 7am thursday morning playing with it, before driving up to
auckland for a customer meeting *grin* - kid in a candy store.....

I was lucky enough to get hold of an HP3585B for 400Euros.
One point I didn't expected is that the fans noise (bearings or something
like this) is, well, pretty present...

Does yours have the same 'feature' or is it just that mine needs some work?

I am (was), from time to time, looking for a used 3577 or 4195 VNA too, but
these are rare and pretty expensive.
I think you've got a good price for yours. Were did you get it?

Being desperate I finally decided to build my own one but, you know, so many
things to do and not enough time...


--
Thanks,
Fred.

 

[Terry Given]

Wes Stewart wrote:

On Fri, 24 Jun 2005 23:52:09 +1200, Terry Given <my_name@ieee.org
wrote:


Joerg wrote:

Hello Terry,


Wow, how did you acquire one of these? Before my retirement I had one
in "my" (Hughes) lab. I seldom used the s-parameter TS, since I also
had available an HP8510C. If I remember correctly (risky propostion
these days), the TS was not a true reversing one where all four
parameters could me measured with one connection. There certainly
wasn't enough trace memory for all four parameters, maybe that was the
limitation. Anyway IIRC you will need software to make full two-port
measurements.


I saved for a while, then spent $2000.


That is a very good price I think. It is a nice analyzer. The only
downside is that it won't function as a spectrum analyzer.

Regards, Joerg

Hi Joerg,

I was pretty happy with it. I figured out your last point while reading
the 3577 datasheet, so I spent $1000 and bought an HP3585A 20Hz - 40MHz
speccy.


I had one of those too in "my" lab. I would sure give a K-buck for
one. Where are you finding these deals?

Now you need an '8566B!

Ebay, see reply to Fred below. whats an 8566B?

cheers
terry

 

[Terry Given]

Wes Stewart wrote:

Terry,

Chapter 2.

http://users.triconet.org/wesandlinda/3577_CH2.pdf

Chapter 3.

http://users.triconet.org/wesandlinda/3577_CH3.pdf

Let me know when you've got this so I can delete it. I'm at my
storage limit.

Also, do you need the HP-IB codes at this time?

Wes

done, thanks, delete at will. and yes please wrt hp-ib codes, although
now I have to save up and buy a usb-hpib adapter. I did some web
browsing, and it looks like it will cost me US$400-$500, the latter
price being the agilent box of tricks (which I will probably get). Looks
like I'd better do some more work (in my now much-better-equipped lab)
to earn enough to pay for it and the s-parameter test set.

Many thanks once again,

Regards
Terry Given

 

[Wes Stewart]

On Sat, 25 Jun 2005 12:08:12 +1200, Terry Given <my_name@ieee.org>
wrote:

Ebay, see reply to Fred below. whats an 8566B?

Um... IMHO the best spectrum analyzer ever built.

 

[Terry Given]

Wes Stewart wrote:

On Sat, 25 Jun 2005 12:08:12 +1200, Terry Given <my_name@ieee.org
wrote:



Ebay, see reply to Fred below. whats an 8566B?


Um... IMHO the best spectrum analyzer ever built.

Wow! 100Hz - 22GHz. A bit rich for my blood though :{

Now that I have the 3585, I can do all of my conducted emissions stuff.
When I eventually get an HF speccy, it only needs to go down to ~ 10MHz,
which (hopefully) means it'll cost less.

So many cool toys, so little cash.

Cheers
Terry

 

[Joerg]

Hello Terry,

done, thanks, delete at will. and yes please wrt hp-ib codes, although
now I have to save up and buy a usb-hpib adapter. I did some web
browsing, and it looks like it will cost me US$400-$500, the latter
price being the agilent box of tricks (which I will probably get). Looks
like I'd better do some more work (in my now much-better-equipped lab)
to earn enough to pay for it and the s-parameter test set.

If you don't need full speed it can be cheaper. I don't know whether
this stuff is available in the US but in Europe they used to be cheaper
than NI:

http://www.plug-in.de/gpib/

Seems prices have gone up since the 300k GPIB is now a whopping 285
Euros. These used to be around $100 or so. They also have a USB-GPIB but
that's really expensive.

Regards, Joerg

http://www.analogconsultants.com