The ESI family of EMI test receivers/analyzers is applicable to full-compliance EMC measurements up to 40 GHz. The ESI is claimed as the fastest EMI receiver available and can make peak-, average- and RMS-detector measurements in just 100 µs. The instrument is a full-certification EMI tester designed in accordance with all relevant commercial and military standards, including CISPR 16-1, an international EMI standard. The family includes three products and covers 20 Hz to 7 GHz (ESI7), 20 Hz to 26.5 GHz (ESI26) and 20 Hz to 40 GHz (ESI40).In addition to making traditional EMC measurements, the ESI instruments are also fully functional spectrum analyzers. A front-panel mode button switches the unit between receiver and spectrum-analyzer modes. Also, a built-in controller function eliminates the need for an external computer to run the EMI software. Also featured is built-in preselection and a switchable preamplifier.