Abstract: The lapping of a facet into a conical diamond tip brazed to a metallic (titanium) shank is controlled by sensing an electrical pulse generated when the diamond facet is enlarged in the vicinity of the titanium shank. A pulse detecting circuit responding to the pulse generates a control signal for energizing a mechanism to lift the stylus from the lapping scaife to cease lapping.

Abstract: A video disc playback system includes a circuit for detecting degradation in signals recovered from a disc and generates a control pulse responsive to the detected degradation. The degradations are of a predetermined duration and represent a predetermined percentage decrease in amplitude. A peak detecting and following circuit is connected for receiving signals recovered from the disc record. The decay rate of the peak detecting circuit is arranged to be substantially equal to a certain minimum duration of amplitude degradations that should occur before it is desired to generate the control pulse. The output signal from the detector circuit is proportioned by a divider circuit and then integrated to produce a signal which is proportional to the average of the detected signal over a relatively long period of time. The proportioned signal is applied to the reference signal terminal of a comparator circuit and the detected signal is applied to the signal input terminal of the comparator.

Abstract: In a video disc player, a carriage is subject to translatory motion in correlation with radial motion of a playback stylus relative to a disc record. A stylus arm carrying the stylus at one end thereof has the other end pivotally secured to the carriage. A permanent magnet is mounted on the stylus arm near its free end. A pair of spaced coils having non-magnetic cores are disposed on the carriage such that the stylus arm-mounted magnet is interposed therebetween. The coils are selectively energized to change the radial location of the stylus relative to the record.