Pickup Head Research Articles

Paper 34: Calibration of Surface Texture Measuring Instruments

Continuously lined surface texture calibration specimens are used to determine the transmission characteristics of surface texture measuring instruments. The lines, deposited at 001 in pitch, are basically sinusoidal in shape with amplitudes ranging from 30 to 1000 μin. Rotating the axis of the specimen relative to the direction of the pick-up head traverse generates waves with pitches ranging from 0·01 to 0·5 in. The transmission characteristics, using 0·01-, 0·03-, and 0·1-in cut-off, of a surface-texture measuring instrument are compared with the requirements of British Standard 1134:1961.

Magnetic film file for computer storage

A 35-mm oxide-coated ifim store is described in which the pick-up head is out of contact with the oxide. The high quality backing medium provided by the film has resulted in complete freedom from drop outs. Interchangeability between all mechanisms has been achieved with available production heads, by using special auto-strobing circuits.

A magnetic recording pickup head with crossed cores of hum balance

This paper describes a simple means of hum balance for a magnetic recording pickup head. Hum level improvements of approximately 20 db are obtained in both single and double coil pickup heads by the method described in this paper.

Magnetic Device for Cuing Film<!--<xref ref-type="other" rid="fn1-10.5594_J12533">*</xref>-->

The magnetic cuing device was designed to eliminate the necessity of cutting notches in the edges of motion picture originals used in film printers. — The method of magnetic cuing consists in painting a small dot of magnetic material on the edge of the film between two perforation holes. The paint may be placed on either the emulsion or base side of the film and still be detected by the low impedance (50-ohm) magnetic detector. — The equipment as designed contains two independent cuing channels, one for controlling printer-light changes and the other for controlling a fade-in or fade-out device which is built in on some printers. A mounting for two extremely small pickup heads has been designed to allow direct replacement of existing notch actuator switches in film printers.