New Technique Accurately Measures Low-Frequency Distortion To <-130 dBc Levels
Emerging high-resolution converters require a very low distortion last stage interface to maintain their >120 dBc SFDR specifications. Typical amplifier distortion measurement techniques usually fail to deliver much more than perhaps 110dBc capability and then only at higher frequencies where the required filters are not setting a limit to the system distortion. A new approach, particularly suited to low frequency distortion measurement, will be described and tested here. This approach eliminates the need for filters while using extremely high-performance, off-the-shelf components to extract the vanishingly low distortion terms of today's high-performance amplifiers. Tested performance at levels previously immeasurable will be shown and the methodology verified.
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