31. Spurious Response, HP 8594EM
31.Spurious Response , HP 8594EMThis performance verication test must be performed with the EMC analyzer set in the spectrum analyzer mode.
This test is performed in two parts. The rst part measures second harmonic distortion; the second part measures third order intermodulation distortion.
To test second harmonic distortion, a 50 MHz low pass lter is used to lter the source output, ensuring that harmonics read by the analyzer are internally generated and not coming from the source. The distortion products are measured using the analyzer marker functions.
For third order intermodulation distortion, two signals are combined in a directional coupler (for isolation) and are applied to the 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). Performing 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.
Equipment Required
Synthesized sweeper (two required)
Measuring receiver (used as a power meter)
Power sensor, 50 MHz to 2.9 GHz
Low pass lter, 50 MHz
Directional coupler
Cable, APC 3.5, 91 cm (36 in) (two required)
Cable, BNC, 120 cm (48 in)
Adapter, Type N (m) to APC 3.5 (m)
Adapter, APC 3.5 (f) to APC 3.5 (f) (two required)
Adapter, Type N (m) to BNC (f)
Adapter, Type N (m) to APC 3.5 (f)
Adapter, Type N (f) to BNC (m)
Performance Verication Tests