Due to supply constraints, the RI8567B4 TIM has been revised to use Apria switches instead of CMC switches. These Apria switches have a different 50 Ω match characteristic.

• Applies to RfMeasure TIMs shipped after May 2024.
• 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.

---

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:
• 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.

---

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.

---

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.

---

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)

---

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: Apria "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 Numbers	1st Ship
CMC	B1	RIF3R14A, RLPS9C0A	2011-05
CMC	B2	RMKUYU0A, RMLNAU0A, RMV5LE0A	2012-04
CMC	B3	PR0NJH0A, RP8MX50A, RP955T0A, RPNXLZ0A, RPRRFE0A, RPSK860A	2013-05
Apria	B4	RPVSJT0A, RPX5YY0A	2014-05
Apria	B5	RIR1F6W0, RR0R0S0A, RR23SR0A, RR2Y360A	2014-07
Apria	B6	RR4X650A, RR5E510A	2014-08
Apria	B7	RR7WBG0A, RR9BVY0A, RRFMBW0A, RRLS4R0A, RTG2CJ0A, R2G2E10A	2017-01
Apria	B8	RVR7YN0A (MISLABELED MVSW081A), RIUGZEK0, RUWA3V0A, RUWA440A, RVCFY80A, RVCG230A, RVR80g0A, RVUM7S0A, RVUMHX0A, RW392B0A	2018-06
Apria	B9	RWFE980A	2020-06
Apria	BA	RWNUHK0A, RXCCYL0A	2021-03

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

TIM Block Diagrams
RI8567BA_Test_Set_12GHz w Cable Lengths.pdf<-- Reflective Switches by Apria
RI8567B2_Test_Set_12GHz.pdf<-- Absorptive Switches by CMC