Due to supply constraints, the RI8567 TIM has been updated to use a different vendor for the RF switches inside the TIM. These new switches have a different 50 Ω match characteristic.

• Applies to RI8567 RfMeasure TIMs shipped after May 2024. (version B4 and later, First 3 Characters of Serial Number are "RPV" and higher)
• See the Table of RI8567B TIMs for affected serial numbers.
• This document provides best‑practice configuration steps to maintain consistent match performance across hardware revisions.

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Symptom

• Mismatch ripple appears in calibrated Fixture paths, where power seems to add or subtract at different frequencies.
• This effect is repeatable and predictable, so final measurements remain valid. Calibration compensates for both source and receiver paths.
• Fixture calibration is hardware‑generation dependent: (see Identifying TIM Hardware Revision)
• B3 and earlier: smoother calibration curves
• B4 and later: ripple visible (see Figure 1) unless best-match configuration is used
• Following the best‑match procedure aligns calibration data across TIM hardware generations.

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Recommendations

• Share this document with engineers comparing Fixture calibration data between B3‑and‑earlier and B4‑and‑later TIMs.
• Avoid swapping TIMs between hardware generations. If swapping is required, perform a full Fixture calibration.
• No software changes are needed, but document and communicate the expected calibration differences (see Figure 1).
• If source match issues are identified, follow the procedure “Update Testplans for Best Match S‑Parameter Measurements”.
• Always update both Fixture Calibration Test Plans and Device Test Plans to use the same switched paths.
• Identify TIM hardware version by:
• Checking in Cassini software, or
• Comparing the serial number sticker with the Table of RI8567B TIMs.

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Procedure – Update Testplans for Best Match S‑Parameter Measurements

1. In Cassini, open the Fixture Calibration Testplan (Test > Cal Plans… or System > Test Objects).
2. Choose Options > Display States.
3. Locate RfMeasure1 Receive Mode entries with value = sPar.
• This routes signals through switch M26 to open port on switch M29, which causes the poor match. (See Figure 5)
4. For RfMeasure1 Rf2 entries with value = Rec:
• Double‑click to view the test panel.
• Change RfMeasure | Rf2 from Receiver → Noise (Noise Source + 6 dB pad) or if RfMeasure | Rf3 is set to Receiver, change to Load.
• Repeat for all sections in the States window.
5. Compile and run the Testplan. Verify reduced mismatch ripple in Fixture calibration data.
6. Save changes (File > Save Guru).
7. Apply the same procedure to Device Testplans.

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Identifying TIM Hardware Revision

Using Equipment Pool:

1. Launch latest Dev or Production Cassini app.
2. Go to System > Equip > Nodes.
3. Select RfMeasure1.
4. Check BaseInst => attribute. The last two digits = hardware revision (e.g., “B7”).

Using Tester Configuration (.TXT file):

1. Launch latest Dev or Production Cassini.
2. Go to System > Tester.
3. Choose Tester > Create Config Log….
4. Save to D:\Shared or a network folder.
5. In the log, find baseInst= under “Fixture Connections” for RfMeasure1.

Reference: Create Config Log (System Description)

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Detailed Explanation of Affected Tests

• RfMeasure | Rf2 button
• Default: set to Receiver, controlling switch M29 → M26.
• Fix: change to Noise (M29 → Noise Source + 6 dB pad).
• RfMeasure | Receive Mode button
• Default: set to s‑parameters, controlling switch M2 → M26.
• Routes RF2 (C7) input to an open, disconnected path.
• Example: When Output Port = RF2, measurements follow a parallel path through coupler + switches → Receiver.

Figure 1: Example Fixture Cal Data showing Mismatch Ripple (>=B4 Reflective on left <=B3 Absorptive on right)


Figure 2: Before and After Best Match Change





Figure 3: New "Rectangle" Switches in rev B4 and after.




Figure 4: CMC "Octagon" Switches in rev B3 and earlier.





Figure 5: Block Diagram Showing Testplan Change (Signal Terminated at Noise Src vs Open)



Table of RI8567B TIMs
Affected instruments are HW Version "B4" and later.

Switch	HW Ver	Serial Number Ranges	Shipped
Old	B1	RIA - RLZ	2011-05
Old	B2	RMK - RMV	2012-04
Old	B3	PR0 - RPS	2013-05
New	B4	RPV - RPX	2014-05
New	B5	RIR - RR2	2014-07
New	B6	RR4 - RR5	2014-08
New	B7	RR7 - R2G	2017-01
New	B8	RVR - RW3	2018-06
New	B9	RWF - RWM	2020-06
New	BA	RWN - RXC	2021-03

As of November 2025, rev BA is the latest hardware revision.

TIM Block Diagrams
RI8567BA_Test_Set_12GHz w Cable Lengths.pdf<-- Switches by New Vendor
RI8567B2_Test_Set_12GHz.pdf<-- Switches by Old Vendor