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Comparison of some WE-030B Impedance Measurements with HP8752C VNA


HP8752C                                                             WE-030B

Arbitrary Load Z

F= 7.18 MHz

Z= 67 - j212                                                          Z= 68 - j211

F= 8.8 MHz

Z= 72.5 + j1.8                                                       Z= 73 + j1.90

F= 10.19 MHz

Z= 78 + j157                                                         Z=82.3 + j158

150 ohm 0603 SMD resistor

F= 30 MHz

Z= 149 + j0.1                                                        Z= 156 - j0.43  ( Measurement effected by DDS spurious - see note 2)

F= 29.999 MHz

Z= 148 + j0.05                                                      Z=149 - j1.07

15 ohm 0603 SMD resistor


F= 30 MHz

Z=15.1 + j0.18                                                      Z= 14 - j0.12  ( Measurement effected by DDS spurious - see note 2)

F= 29.999 MHz

Z=15.1 + j0.13                                                      Z=15.2 - j0.26

F=3.5 MHz                                                           

Z=15.0 - j0.02                                                      Z=15.0 - j0.21


50 ohm Calibration Termination

F= 30 MHz

Z=50 + j0.01                                                         Z= 49.9 -  j0.05

F= 29.999 MHz

Z= 50 - j0.01                                                        Z= 49.9 - j0.00

Notes

1) Both HP8752C and WE-030A were calibrated with the same short, open and load terminations ( Accurate SMA Types )

2) With the WE-030B, accuracy is limited mainly by the non-linearity of the phase detector, the non-linearity of the amplitude detector and DDS spurious. The DDS produces some extra spurious effect at frequencies of 25 MHz and 30 MHz.

Overall accuracy is estimated as: better than +- 5% for the magnitude of the reflection coefficient,  and better than +- 2 degrees for its angle.
All other displayed parameters are mathematically derived from the reflection coefficient.

Conclusion

The WE-030B provides good accuracy for an instrument of this type.