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Hello group:
Does anybody have the service manual of the 35677A S parameter test set?
All I need to know is what the pin out of the little connector on the
back?
I am trying to change the internal mechanical coaxial switch for a
solid state one and use the S parameter with my own LF network analyzer.

I looked but couldnt find a source for download online, anyway its not really rocket science, the connector basically only controls a SPDT switch that switches the RF from the source to either the A or B coupler, there is no step attenuator or anything else to control in the box.
When replacing the mechanical with a solid state switch there are a few things you should keep in mind:

a.) the original switch terminates the unused arm in 50ohm, this condition needs to be fullfilled by your solid state switch as well !

b.) low frequency boundary
many solid state switches are based on GaAs and suffer from poor low frequency performance, pin switches are even worse, the solid state switch used in the 85046A for example exhibits poor RF characteristics below 100KHz

c.) isolation
the mechanical switches have fairly high isolation, get a datasheet of the Agilent 8763A (this is what they used) your Solid state switch needs to be equal or better !



marsac1212 <marsac1212@...> wrote:
Hello group:
Does anybody have the service manual of the 35677A S parameter test set?
All I need to know is what the pin out of the little connector on the
back?
I am trying to change the internal mechanical coaxial switch for a
solid state one and use the S parameter with my own LF network analyzer.






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Planning to use mini-circuits
ZASWA-2-50DR

1.- Yes it is absorptive type i.e 50 ohm terminated
2.-The switch is DC coupled, so LF does not seem to be a problem...
likely it is not PIN based.
3.- Isolation is about 90 db in the range of interest... it will
never beat the 100 dB of a mechanical switch but it will last almost
forever....besides that I think I can take care of the isolation with
a 12 term 2 port correction. Given that the 3577A can not do that
type of correction.

a.) the original switch terminates the unused arm in 50ohm, this

condition needs to be fullfilled by your solid state switch as well !

b.) low frequency boundary
many solid state switches are based on GaAs and suffer from

poor low frequency performance, pin switches are even worse, the
solid state switch used in the 85046A for example exhibits poor RF
characteristics below 100KHz

c.) isolation
the mechanical switches have fairly high isolation, get a

datasheet of the Agilent 8763A (this is what they used) your Solid
state switch needs to be equal or better !

marsac1212 <marsac1212@...> wrote:
Hello group:
Does anybody have the service manual of the 35677A S parameter test

set?

All I need to know is what the pin out of the little connector on

the

back?
I am trying to change the internal mechanical coaxial switch for a
solid state one and use the S parameter with my own LF network

analyzer.

---------------------------------
Get easy, one-click access to your favorites. Make Yahoo! your

homepage.