The MN63A/65A/72A/64B provide GPIB as a standard feature and are suitable for automatic measuring system components used in R&D, inspection, or production. The 50 ohm models are available in four different frequency ranges, which can be selected to match the application for maximum economy. The attenuation calibration value is stored in the internal memory and can be uploaded to the system controller for checking against measured values, permitting a significant increase in system accuracy. A relative setting function is also provided, which allows measurement to be referenced to any arbitrary level. Rotary encoders are standard, allowing simple, smooth setting under manual control.