Fluke 5720A connector is connected back to the OUTPUT HI SENSE and OUTPUT LO SENSE binding posts

Theory of Operation 2

Analog Section Detailed Circuit Description

connector is connected back to the OUTPUT HI SENSE and OUTPUT LO SENSE binding posts.

Attenuation is calibrated starting with 70 dB and decreased in 10 dB steps to 0 dB. The Switch Matrix assembly connects the output of the Wideband AC module to its internal cal zero amplifier circuit during all attenuator calibrations except the 0 dB and 10 dB.

The internal cal zero amplifier circuit provides a gain of 10 to Wideband output during 20 dB to 70 dB attenuation calibration. The output of this amplifier is connected to the RCL line which is routed to the +input of the adc circuit on the DAC assembly. Output from the DAC is connected to the -input of the adc circuit and adjusted until a null is achieved. The exact attenuator value is then determined.

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