Abstract: A cantilever control device is provided that can prevent, in an atomic force microscope, self-excited oscillation of a cantilever from stopping and prevent a probe of the cantilever from coming into contact with a measurement object. In the atomic force microscope, a cantilever control device 1 is constituted from a cantilever 10 having a probe 12, an actuator 20 that causes self-excited oscillation in the cantilever 10, an oscillation velocity detector 30 that detects the oscillation velocity of the cantilever 10, a displacement calculator 32 that calculates the oscillation displacement of the cantilever 10, and a controller 40 that generates a signal for driving the actuator 20. A feedback control signal S is represented as (K?G·x2)·dx/dt, where x is the oscillation displacement of the cantilever 10, dx/dt is the oscillation velocity of the cantilever 10, and both K and G are feedback gains of a positive value.

Abstract: A floating point arithmetic system including an operating processor for effecting the floating point operation, a memory device for storing data to be operated and a processing device for controlling the data transfer between the operating processor and the memory device and the operating process to be executed, wherein the processing device, memory device and operating processor are mutually connected by means of an address control bus line, and the processing device and memory device are connected to each other by means of a data bus line. In the processing device, there is generated an instruction signal which includes an address code representing an address of data to be operated and an instruction code denoting the content of operation to be executed, and the instruction signal is supplied to the memory device and operating processor via the address control bus line.