A prototype for a time-domain EMI measurement system using pipelined time-interleaved ADCs up to 4 GHz

The limited frequency range covered by state of the art analog to digital converter (ADC) technology requires the application of RF down converting methods to extend the frequency range of real-time time-domain EMI measurement systems beyond 1 GHz. In this paper the concept of Time Interleaved Sampling is introduced to extend the frequency range of time domain EMI measurement systems. It is shown that the application of time interleaved sampling with three ADCs can increase the baseband range of the measurement system up to 4 GHz. In this work the successful implementation and experimental investigation of such a system is described. The system was calibrated using a harmonic test signal. A 40 dB spurious free dynamic range (SFDR) was achieved, fulfilling the CISPR standard requirements for an emission measurement system. Measurements in the frequency range of 30 MHz-3 GHz has been carried out demonstrating the broad- and narrowband performance of this novel system.