HP 8590 E-Series, Руководство по калибровке

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29. Spurious Response ,
HP 8591EM
This performance verication test must be performed with the EMC analyzer set
in the spectrum analyzer mode.
This test is performed in two parts . P art 1 measures second harmonic distortion;
part 2 measures third order intermodulation distortion.
T o test second harmonic distortion, a 50 MHz low pass lter is used to lter the
source output, ensuring that harmonics read by the EMC analyzer are internally
generated and not coming from the source . T o measure the distortion products ,
the power at the mixer is set 25 dB higher than specied. New test limits have
been developed based on this higher power .
With 045 dBm at the input mixer and the distortion products suppressed
by 70 dBc , the equivalent Second Order Intercept (SOI) is +25 dBm
(045 dBm + 70 dBc). Therefore , with 020 dBm at the mixer , and the distortion
products suppressed by 45 dBc , the equivalent SOI is also +25 dBm (020 dBm +
45 dBc).
F or third order intermodulation distortion, two signals are combined in a
directional bridge (for isolation) and are applied to the EMC analyzer input. The
power level of the two signals is 8 dB higher than specied, so the distortion
products should be suppressed by 16 dB less than specied. In this manner , the
equivalent third order intercept (TOI) is measured.
With two 030 dBm signals at the input mixer and the distortion products
suppressed by 70 dBc , the equivalent TOI is +5 dBm (030 dBm + 70 dBc/2).
However , if two 022 dBm signals are present at the input mixer and the
distortion products are suppressed by 54 dBc , the equivalent TOI is also +5 dBm
(022 dBm + 54 dBc/2).
P erforming the test with a higher power level maintains the measurement
integrity while reducing both test time and the dependency upon the source's
noise sideband performance .
2-180 P erformance V erication T ests