Method described and concept proofs presented for using stored wideband RF ATE site information to "virtually" calibrate an NWA with customized narrowband calibrations.

1. data-Based Wideband NWA Calibrations
Presentation Concepts by Stephen Nibblett Jan 16, 2013
(Project Kick-Off Presentation Originally created Sept 17, 2010)

2. “dBWCAL” CONCEPT

3. Wide-Band
Characterization at
Variable Sample
Rates Established
Wide-Band Data Table
Established
(Custom Table per ATE)
Error Terms
800
900
2100 1900
Network
Database
Product Test Frequency Ranges
and Power Levels Determined
1) Network Setup
• Exact Test Ranges and Accuracies identified and cataloged, kept updated
• Custom Wideband RF Paths Error Term data set instance created (per site)
• Note: sample point densities are intentionally NOT uniform across wideband range, customized as needed!

4. NWA Measurement Of Cal
Standards
(USB Controlled E-Cal)
ATE Rack
Characterization
App
Network
Database
Save Wide-Band
“Custom” Data Table
2) ATE Rack Characterization
• Custom Wideband RF Paths Error Term data set measured at test site
• Characterization Intervals and Times scheduled “Offline” from Production

5. Product Narrow-Band
Test Frequency Ranges
NWA Calibrations
Created at ATE
Rack from Custom
Error Terms
- Product Selection
- Station Selection
- NB Error Term
Interpolations
Management Test
Plan App
(Local or Remote)
Network
Database
Saved Wide-Band
“Custom” Data
Table
3) ATE Rack Setup and Usage
• Product Line Management plans product(s) to be tested at ATE site for shift
• Custom Interpolated Error Terms created for required site NWA calibrations
• ATE software engine pulls Error Terms and saves local NWA calibrations

6. •6
“dBW CAL” METHOD

7. EXISTING CAL Methods: Cal Concept
• What Is Contained In A Cal File?
o The Error Corrections!
NWADUT
RF
PATHS
System Errors

8. • Internally Calculated Corrections:
• NWA based processing
• Based on assumed “known” coeff values:
• “Fitting” errors present
• “Actual” coeffs maybe not correct!
• STNDs re-connected for every cal/path:
• redundant actions, time wasted
• poor repeatability (cable moves)
• Minimum Correction Solution:
• 3 unknowns; 3 standards (S,O,L)
OLD CAL Method: Manual SOL Cal
Short coeff
Open coeff
Load
Thru
Expected
NWA
Meas Short
Meas Open
Meas Load
Meas Thru
Actual

9. OLD CAL Method: Manual SOL Cal
NWA MEAS
RF
PATHS
System Errors
Meas STNDs
STND Coeffs NWA CPUNWA MEM
NWA CPU
Compute System Errors
NWA Cal
Estimated
RAW
Measured
Correction
File
Meas Frequency
Information

10. • Externally Calculated Corrections:
• Network based processing
• Based on assumed “known” coeff values:
• “Fitting” errors present
• “Actual” coeffs maybe not correct!
• STNDs connected once for every cal/path:
• reduced actions, time saved
• better repeatability (less cable moves)
• Minimum Correction Solution:
• 3 unknowns; 3 standards (S,O,L), STILL OLD TECHNOLOGY!!
OLD CAL Method: ATE “Optimized” Cal
Short coeff
Open coeff
Load
Thru
NWA
Meas Short
Meas Open
Meas Load
Meas Thru
Network

11. OLD CAL Method: ATE “Optimized” Cal
NWA MEAS
RF
PATHS
System Errors
Meas STNDs
STND Coeffs FELIXSQL TABLE
FELIX
Compute System Errors
NWA Cal
Estimated
RAW
Measured
Correction
File
Meas Frequency
Information
RAW
MEAS

12. • Internally Calculated Corrections:
• NWA based processing
• Based on known data values (w/ uncertainty):
• “Fitting” errors NOT present
• Broadband “Actual” data is well known
• ECAL re-connected for multi-port (>4) cals:
• redundant actions, time wasted
• ok repeatability (but cables still moved)
• Over-Determined, Data-Based Correction:
• 3 unknowns; 4 imp states (Z1, Z2, Z3, Z4), MORE MODERN!!!
NEWER CAL Method: Agilent E-Cal
Z1 Data
Z2 Data
Z3 Data
Z4 Data
NWA
Meas Z1
Meas Z2
Meas Z3
Meas Z4
ECAL

13. NEWER CAL Method: Agilent E-Cal
NWA MEAS
RF
PATHS
System Errors
Meas STNDs
STND DATA NWA CPUNWA MEM
NWA CPU
Compute System Errors
NWA Cal
ACTUAL
RAW
Measured
Correction
File
Meas Frequency
Information

14. dBWCAL Method: Network dB Cals
Externally Calculated Corrections:
• Network based SQL table processing, using modern techniques (WLS)
• Broadband Cal Set Data is stored, used “on-demand”
Based on known data values: Data-Based Cal (gathered round-robin):
• “Fitting” errors present, but always corrected
• “Actual” data is acceptably correct, with uncertainty well known
MULTI-PORT CAL SET (w/ECAL) connected once for multi-port (>4) cals:
• NO redundant actions, NO time wasted, and OFFLINE OPERATION!
• BEST repeatability (cables moved only once); can also incorporate test jig!
Over-Determined Correction Solutions:
• 3 unknowns; 4 (or more) imp states (Z1, Z2, Z3, Z4)

15. dBWCAL Method: Network dB Cals
NWA
Network
Cal Set (dBCAL)
Stored Data Table:
:ECAL (or MANUAL) “Offline”
Stored Data Table:
Meas Data dBCal
:Broadband
:Multi-path
:Multi-pwr
“Online”
USER select
typecodes
Network
generates ONLY
needed corrections:
interpolated / interpreted
from unique instance of
Stored Table: Meas Data dBCAL
Gold Stnd
checks cals
“Offline”
Gold Stnd
checks cals:
no re-cal
if acceptable
“Round Robin”
Data Analysis
1
1a
1b
1b
2a
2b
3a
3b
3c

16. dBCAL Method: Network dB Cal “offline”
NWA MEAS
RF
PATHS
System Errors
Meas STNDs
STND DATA ATE EngineSQL TABLE
SQL TABLE
ACTUAL
BROADBAND
STND DATA
RAW BENCH
BROADBAND
MEAS DATA
Meas Frequency
Information
RAW
MEAS
SAVED FOR DESIGNATED LIMITED LIFETIME OF “VALID” ONLINE USAGE…

17. INTERPOLATE ERRORS
dBCAL Method: Network dB Cal “online”
Network APP
SELECT
TYPECODE
ATE EngineSQL TABLES
Narrowband NWA
Correction Files
Meas
Information
NWA Cal
BENCH
BROADBAND
ERROR DATA
INTERPOLATED
NARROWBAND
CORRECTIONS
TRANSLATE FOR NWA
MEAS
GOLD STND
USER
MEAS
TYPECODE
BENCH
BROADBAND
ERROR DATA
INTERPOLATED
NARROWBAND
ERROR DATA

18. dBWCAL Phase II:
Interpolated Cal Experiment

19. dBWCAL Method: Projected Goals
• Store Wideband Bench Characterization
o Requires “Relatively Flat” Bench Response
o OR Requires Sufficient # Of Data Points
• Retrieve Narrowband Requirement
o Define Necessary DUT Measurement Parameters
• Interpolate NB Bench Calibration
o NWA & Bench Switch Error Terms Included
• Format & Save NWA CAL FILE

20. dBWCAL Method: Experiment Goal
• Demonstrate Cal Interpolation Feasibility
• Discover & Define All Critical Requisites

21. dBWCAL Method: Interpolation Process
• Extract Narrowband Cal Information
From Wideband S2P Cal Files:
• Optimally: ENA+Rack Path Characterization
• For Experiment: Calibrate Wideband On ENA
• Interpolate Frequency and Data Points
• Optimally: Use Weighted Least Squares
• For Experiment: Use On-Board ENA Interpolation

22. dBWCAL Method: Experiment “A” Plan
• Calibrate VNA Wideband .1 MHz to 4500MHz
o (1601, 6401, 20001) Points (requires 5071C)
o Use Same Cal Kit for Narrow and Wideband
• E-Cal Module is BEST
o Repeat Below (2) Steps For Each Point Setting
• Set Start/Stop to 1830-2000MHz, 401 Points
o ENA Automatically Interpolates Calibration: DO NOT RE-CAL!!!
• Gather S2P Files For Narrowband DUT
Then:
• Recalibrate ENA Narrowband, Same Parameters
• Gather DUT Narrowband S2P File (Control)

23. dBWCAL Method: Experiment “A” Reporting
• Using Excel, Plot ALL S2P Data:
o 401 Point ACTUAL NB Calibration “Control”
o 1601 Point WB Cal Interpolated For 401 Points
o 6401 Point WB Cal Interpolated For 401 Points
o 20001 Point WB Cal Interpolated For 401 Points
• Create “Variance” Plots
o Compare Accuracy Of Each Interpolated Cal
o Use “Control” 401 Point Cal Data for Baseline

24. dBWCAL Method: Experiment “A” Results
• S11 Log Mag Data Correlation: Excellent
o Note: Return Loss Differences Past 30dB Is Insignificant
Accuracy
Critical
Don’t Care!

25. dBWCAL Method: Experiment “A” Results
• S11 Log Mag Passband Data Correlation: Excellent
o Note: Range Differences for Return Losses Past 30dB Is Insignificant
• Baseline Variation Plot Of (TX) Passband:
o Maximum Variation Occurs At Points Past 30dB Return Loss
o Note: Variation Includes Test Cable Connection Repeatability

26. • S11 Phase Passband Data Correlation: Excellent
o Note: MOST Rejection Variation Due to NO AVERAGING & Hi IF BW
dBWCAL Method: Experiment “A” Results

27. • S11 Phase Passband Data Correlation: Excellent
o Note: Return Loss Differences Past 30dB Is Insignificant
• Baseline Variation Plot Of (TX) Passband:
o Maximum Variation Occurs At Points Past 30dB Return Loss
o Note: Variation Includes Test Cable Connection Repeatability
dBWCAL Method: Experiment “A” Results

28. • S22 Log Mag Data Correlation: Excellent
o Note: Range Differences for Return Losses Past 30dB Is Insignificant
dBWCAL Method: Experiment “A” Results

29. • S22 Log Mag Passband Data Correlation: Excellent
o Note: Range Differences for Return Losses Past 30dB Is Insignificant
• Baseline Variation Plot Of (TX) Passband:
o Maximum Variation Occurs At Points Past 30dB Return Loss
o Note: Variation Includes Test Cable Connection Repeatability
dBWCAL Method: Experiment “A” Results

30. • S22 Phase Passband Data Correlation: Excellent
o Note: MOST Rejection Variation Due to NO AVERAGING & Hi IF BW
dBWCAL Method: Experiment “A” Results

31. • S11 Phase Passband Data Correlation: Excellent
o Note: Range Differences for Return Losses Past 30dB Is Insignificant
• Baseline Variation Plot Of (TX) Passband:
o Maximum Variation Occurs At Points Past 30dB Return Loss
o Note: Variation Includes Test Cable Connection Repeatability
dBWCAL Method: Experiment “A” Results

32. • S21 Log Mag Data Correlation: Excellent
o Note: MOST Rejection Variation Due to NO AVERAGING & Hi IF BW
dBWCAL Method: Experiment “A” Results

33. • S21 Log Mag Band Edge Data Correlation: Excellent
o Note: MOST Rejection Variation Due to NO AVERAGING & Hi IF BW
o ALL Measurements are Same #Points, IF BW, Power, Freq Span
• Correlation Plot Of Low-Side Attn Slope / Band Edge:
dBWCAL Method: Experiment “A” Results

34. • S21 / S12 Log Mag Slopes Data Correlation: Excellent
o Note: MOST Rejection Variation Due to NO AVERAGING & Hi IF BW
o Measurements are Same #Points, IF BW, Power, Freq Span
• Baseline Variation Plot Of Low-Side Attn Slope / Band Edge:
o Note: Variation Includes Test Cable Connection Repeatability
dBWCAL Method: Experiment “A” Results

35. • S21 Log Mag Passband Data Correlation: Excellent
o ALL Measurements are Same #Points, IF BW, Power, Freq Span
• Baseline Variation Plot Of Passband:
o Note: Variation Includes Test Cable Connection Repeatability
dBWCAL Method: Experiment “A” Results

36. • S21 Phase Data Correlation: Excellent
o Note: MOST Rejection Variation Due to NO AVERAGING & Hi IF BW
dBWCAL Method: Experiment “A” Results

37. • S21 Phase Passband Data Correlation: Excellent
o ALL Measurements are Same #Points, IF BW, Power, Freq Span
• Baseline Variation Plot Of Passband:
o Note: Variation Includes Test Cable Connection Repeatability
dBWCAL Method: Experiment “A” Results

38. • S12 Log Mag Data Correlation: Excellent
o Note: MOST Rejection Variation Due to NO AVERAGING & Hi IF BW
dBWCAL Method: Experiment “A” Results

39. • S12 Log Mag Band Edge Data Correlation: Excellent
o Note: MOST Rejection Variation Due to NO AVERAGING & Hi IF BW
o ALL Measurements are Same #Points, IF BW, Power, Freq Span
• Correlation Plot Of (TX) Low-Side Attn Slope / Band
Edge:
o Note: Variation Includes Test Cable Connection Repeatability
dBWCAL Method: Experiment “A” Results

40. • S21 / S12 Log Mag Slopes Data Correlation: Excellent
o Note: MOST Rejection Variation Due to NO AVERAGING & Hi IF BW
o Measurements are Same #Points, IF BW, Power, Freq Span
• Baseline Variation Plot (TX) Low-Side Attn Slope /Band Edge
o Note: Variation Includes Test Cable Connection Repeatability
dBWCAL Method: Experiment “A” Results

41. • S12 Log Mag Passband Data Correlation: Excellent
o ALL Measurements are Same #Points, IF BW, Power, Freq Span
• Baseline Variation Plot Of Passband:
o Note: Variation Includes Test Cable Connection Repeatability
dBWCAL Method: Experiment “A” Results

42. • S21 Phase Data Correlation: Excellent
o Note: MOST Rejection Variation Due to NO AVERAGING & Hi IF BW
dBWCAL Method: Experiment “A” Results

43. • S12 Phase Passband Data Correlation: Excellent
o ALL Measurements are Same #Points, IF BW, Power, Freq Span
• Baseline Variation Plot Of Passband:
o Note: Variation Includes Test Cable Connection Repeatability
dBWCAL Method: Experiment “A” Results

44. dBWCAL Method: Experiment “A” Summary
• 1601 Points
o Adequate Accuracy For Most Passband Measurements
• Passband Transmission Log Mag Measurements
• Passband Transmission Phase Measurements
o Adequate Accuracy For Most Attn Slope Measurements
• Attenuation Slope Transmission Log Mag Measurements
• 6401 Points
o Most Results Very Similar to 1601 Points
• 20001 Points
o Most Accurate Tracking For “Sensitive” Measurements
• Transmission Rejection Log Mag Measurements
• Passband Reflection Phase Measurements

45. • WB-NB Interpolated Calibrations Are
Valid
• Initial Recommendations:
o Perform Wideband Bench Characterizations
o Use 20001 Points For All Characterizations
• Before Recommendations Are Final
o Re-Check 1601, 6401 Interpolations, for speed:
• For “Sensitive” Meas Use AVG, Lower IF BW
dBWCAL Method: Experiment “A” Conclusion

46. •46
“dBW CAL” CONCEPT: To Be Continued?