Comparing CalRdy, QuickCal and 2-port cal on N9923A A filter test Prepared by: Afsi Moaveni
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Comparing CalRdy, QuickCal and 2-port cal on N9923A A filter test Prepared by: Afsi Moaveni Last update: May 12, 2010
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Comparing CalRdy, QuickCal and 2-port cal on N9923A A filter test Prepared by: Afsi Moaveni Last update: May 12, 2010. Filter Measurement on N9923A. (3) QuickCal or 2-port cal reference plane is at DUT. (1) Note black cable connecting test port to filter. - PowerPoint PPT Presentation
Transcript of Comparing CalRdy, QuickCal and 2-port cal on N9923A A filter test Prepared by: Afsi Moaveni
Comparing CalRdy, QuickCal and 2-port cal on N9923A A filter test
Prepared by:Afsi MoaveniLast update: May 12, 2010
Filter Measurement on N9923A
(1) Note black cable connecting test port to filter.
(2) CalRdy reference plane is at test port.
(3) QuickCal or 2-port cal reference plane is at DUT.
N9923A
QuickCal performed with a load.
Filter Measurements – Full 2-port cal
S21 magnitude - entire trace. zoomed out
S21 of bandpass filter
1.020 1.040 1.060 1.080 1.100 1.120 1.140 1.160
-140.00
-120.00
-100.00
-80.00
-60.00
-40.00
-20.00
0.00
S21 Mag CalRdy S21 Mag 2-port Cal S21 Mag QuickCal
S21 magnitude – passband. zoomed in.
With CalRdy, slightly more loss in the passband of the filter because the black cable that connects the filter to the test ports is not accounted for with CalRdy.
2-port cal and QuickCal nearly identical.
1.080 1.085 1.090 1.095 1.100
-6.00
-5.00
-4.00
-3.00
-2.00
-1.00
0.00
S21 Mag CalRdy S21 Mag 2-port Cal S21 Mag QuickCal
S21 phase – entire trace. zoomed out.
1.020 1.040 1.060 1.080 1.100 1.120 1.140 1.160
-200.00
-150.00
-100.00
-50.00
0.00
50.00
100.00
150.00
200.00
S21 Phase CalRdy S21 Phase 2-port Cal S21 Phase QuickCal
Rejection band of filter – noisy
measurements (90-100 dB loss S21) measurement s
S21 phase – passband. zoomed in.
CalRdy is offset from 2-port cal and QuickCal because we have not compensated for the extra delay in the cable.
2-port cal and QuickCal nearly identical.
1.080 1.085 1.090 1.095 1.100
-200.00
-150.00
-100.00
-50.00
0.00
50.00
100.00
150.00
200.00
S21 Phase CalRdy S21 Phase 2-port Cal
S21 Phase QuickCal
S11 magnitude – entire trace. zoomed out.
Return loss in passband better than 15 dB.
1.040 1.060 1.080 1.100 1.120 1.140
-60.00
-50.00
-40.00
-30.00
-20.00
-10.00
0.00
10.00
S11 Mag CalRdy S11 Mag 2-port Cal S11 Mag QuickCal
S11 phase – entire trace. zoomed out.
Much variation observed. Can be explained if you zoom in. See next slide.
1.040 1.060 1.080 1.100 1.120 1.140
-200.00
-150.00
-100.00
-50.00
0.00
50.00
100.00
150.00
200.00
S11 Phase CalRdy S11 Phase 2-port Cal S11 Phase QuickCal
S11 magnitude – passband. zoomed in.
CalRdy is a bit different. Test port cable effects not corrected for.
QuickCal and 2-port cal similar.
1.080 1.085 1.090 1.095 1.100
-60.00
-50.00
-40.00
-30.00
-20.00
-10.00
0.00
S11 Mag CalRdy S11 Mag 2-port Cal S11 Mag QuickCal
S11 phase – passband. zoomed in.
Phase with CalRdy is off, because of length of cable.
Phase difference between 2-port cal and QuickCal observed because S11 magnitude is very good. Return loss in the 20-40 dB range.
Next slide shows reject band.
1.080 1.085 1.090 1.095 1.100
-200.00
-150.00
-100.00
-50.00
0.00
50.00
100.00
150.00
200.00
S11 Phase CalRdy S11 Phase 2-port Cal S11 Phase QuickCal
S11 phase – reject band. zoomed in.
Phase with CalRdy is off because of length of cable.
2-port cal and QuickCal nearly identical.
1.040 1.045 1.050 1.055 1.060 1.065 1.070 1.075 1.080
-100.00
-80.00
-60.00
-40.00
-20.00
0.00
20.00
40.00
60.00
80.00
100.00
S11 Phase CalRdy S11 Phase 2-port Cal S11 Phase QuickCal
Approximate measurement uncertainties
2-port Cal QuickCal Notes
5 dB RL S11 mag 0.3 dB 0.4 dB When S11 is poor, results are quite similar and uncertainties similar.
S11 phase 2 deg 2.5 deg
20 dB RL S11 mag 0.8 dB 1 dB
S11 phase 6 deg 7 deg
40 dB RL S11 mag 5 dB 7 dB S11 is excellent. Uncertainty is a lot more with QuickCal.
S11 phase 50 deg 110 deg
5 dB IL S21 mag 0.07 dB 0.08 dB Similar performance.
S21 phase 0.5 deg 0.5 deg
Summary of results
CalRdy good for magnitude – if cable/attenuators have low loss or if it is a pass/fail test with wide margins.
QuickCal very good for magnitude. QuickCal good for phase if return loss of device is between 0 and 15 dB approximately.
2-port cal always the most accurate.
