Abstract: A video signal recording mode detecting apparatus is provided to detect a plurality of recording modes in which frequencies of the carriers in FM video signals are different. By counting the number of pulses that result from wave-shaping the carrier of an FM video signal during a predetermined period, it is possible to detect the particular video signal recording mode being employed. By using a digital detecting mode circuit recording modes having different carriers can be positively detected by relative small-scale circuits suitable for fabrication as integrated circuits.

Abstract: A video signal processing circuit for an input video signal having a DC level, a pedestal level, and a blanking period, includes a first clamp circuit for clamping the pedestal level of the input video signal to a first predetermined DC level in response to a clamp voltage supplied from a clamp voltage source, a blanking circuit for setting the level of the input video signal to a second predetermined DC level which is higher than the pedestal level of the input video signal during the blanking period of the input video signal and for producing a wave-formed signal, a peak-hold circuit for detecting and holding the darkest level of the wave-formed signal and for producing a peak-held signal, a series circuit of a diode and resistor, which produces a threshold level signal, connected between the first clamp circuit and the output of the peak-held circuit, a comparator circuit supplied at one input with the lower of the threshold level signal and the peak-held signal and supplied at another input with the outpu

Abstract: The time for positioning of a machine under numerical control is determined so that the positioning is finished at the moment when the amplitude of vibration of the machine is reduced to zero. In the thus predetermined time at least accelerating control and decelerating control are conducted to achieve control for positioning the machine at a commanded position.