The SIM984 is a wide bandwidth, low noise isolation amplifier. It has a gain of up to x100 and a bandwidth up to 1 MHz. The input stage is floating and is optically coupled to the output stage which is chassis grounded. The input signal can float up to 1000 V above or below ground. DC output offset can be adjusted from the front panel with a small screwdriver. In addition to measuring isolated signals, the SIM984 can also be used to break ground loops and reduce common-mode interference.