How Can I compare measurements of different appraiser for a same product

[Raquel]

I am testing a device (RF filter) which uses an external PCB matched fixture however we have big problems with this external matching (Return Loss problems) because the electronic components are so susceptible to damage so I want to use a new Network Analyzer software matching fixture to test it. I performed a correlation between them and Change the Test Data Sheet in order to change the spec. However meaurements obtained with the external matched one and the software matched fixtures are too different. And I don't know how to compare them. I have the electrical data using both fixtures and electrical test data of rejects which passed electrical test with GPPO fixture but not with external matching fixture. Does anyone have any idea? What I really don't know is what I must put in my report? Any light?


Thanks in advance

Raquel

[Al Rosen]

Originally Posted by Raquel

I am testing a device (RF filter) which uses an external PCB matched fixture however we have big problems with this external matching (Return Loss problems) because the electronic components are so susceptible to damage so I want to use a new Network Analyzer software matching fixture to test it. I performed a correlation between them and Change the Test Data Sheet in order to change the spec. However meaurements obtained with the external matched one and the software matched fixtures are too different. And I don't know how to compare them. I have the electrical data using both fixtures and electrical test data of rejects which passed electrical test with GPPO fixture but not with external matching fixture. Does anyone have any idea? What I really don't know is what I must put in my report? Any light?


Thanks in advance

Raquel

1. What does GPPO mean?
2. Other than damage to your matching test fixture were there any other problems with the test fixture?
3. Did the filter always meet the customers expectations after passing your testwith the old fixture?
4. Can you attach a file with the test data for filters (more than one) tested on both systems along with the specifications for the filter?

[Raquel]

Hello Al and Thank you at least one person is interested in what i have to do.


What does GPPO mean?
This is only the name of a fixture without external matching.

Other than damage to your matching test fixture were there any other problems with the test fixture? Really not, if their components are good the fixture is OK.

Did the filter always meet the customers expectations after passing your test with the old fixture? Well, this is hard to answer because I must say Yes, if they passed the electrical test they always meet the customer specification. However if there is something that affects the part mechanically maybe they couldn't meet them.

Can you attach a file with the test data for filters (more than one) tested on both systems along with the specifications for the filter? I want to do it, but I can't because this is propietary.

[Al Rosen]

Originally Posted by Raquel

Hello Al and Thank you at least one person is interested in what i have to do.


What does GPPO mean?
This is only the name of a fixture without external matching.

Other than damage to your matching test fixture were there any other problems with the test fixture? Really not, if their components are good the fixture is OK.

Did the filter always meet the customers expectations after passing your test with the old fixture? Well, this is hard to answer because I must say Yes, if they passed the electrical test they always meet the customer specification. However if there is something that affects the part mechanically maybe they couldn't meet them.

Can you attach a file with the test data for filters (more than one) tested on both systems along with the specifications for the filter? I want to do it, but I can't because this is propietary.

You haven't given us enough information. What tests are you performing and which test are faiing? What does the fixture do, other than match impedance? I don't have enough information.

[Raquel]

Thanks Al, and sorry I will try to explain as much as I can...


I am measuring a 1960 MHz RF Filter BW 60 MHz.
I performed Maximun Loss measurements (1930 to 1990 MHz), Bandedge measurements to 4.79, 8, 10, 12 and 13 dB, Amplitude Variation, Minimun Rejection Measurements and Return Loss measuremets in S11 and S22 ports.

My external matched fixture use a SerC 13.54 pF in Port 1 Matching and SerC 40.6 pF.

And we try to simulate this same values using the network, however I can not get a good simulation of the signal... it is good in the bandedge measurements but not in the Loss and specially in the return Loss measurements (See the attached file)

So I perform a correlation between the data I got with my external fixture with the one I get with the software matched fixture and change my TDS.

I know this matching via software looks too different...so I want to request a change, however I want to bring my report some more technical data in order to request that because this is matching was performed by the test Manager (my boss) and I want to bring him good information...

What I did to get the information was:

Test 1 reel (5K pcs only) of parts with matched existing fixture. All the rejects were saved.
Run a restest lot w/rejects for that reel using GPPO and TECO TDS developed previously.
Test manually all the rejects that passed electrical test with GPPO fixture in order to confirm them.

The results were:

I got 17 failures 3 IL, 13 VSWR/REtun Loss and 1 Upper Bandedge at 4 dB Faliures with my external matched fixture.

And 2 IL and 2 UpperBandedge Failures at 4 dB with my GPPO fixture.

So it is not catching and screening out all the failures...

This is easy to say, but what Can I conclude of this results????


Thanks