Portal de Periódicos da CAPES

Development and Design of the Ampex Auto Scan Tracking (AST) System

1980; Society of Motion Picture and Television Engineers; Volume: 89; Issue: 12 Linguagem: Inglês

10.5594/j02048

0036-1682

R. A. Hathaway, Ray Ravizza,

Piezoelectric Actuators and Control

Several years ago Ampex recognized the need for a new generation of high-writing-speed, one-field-per-scan video recorders that would have low initial and operating costs, while offering a simple but effective internal editing facility. A program was also established to investigate the feasibility of improving the slow motion capability of such a recorder. Various systems were considered; however, a head that moved relative to the rotating portion of the scanner and, therefore, transverse to the recorded track on the tape was ultimately selected. Two approaches to physically moving the head transverse to the recorded track were considered in some detail. The approach decided upon uses a piezoelectric element onto which the head transducer is mounted. A bi-morph bender element configuration was found to be ideal. This type of system formed the basis for the development of the Auto Scan Tracking (AST) system used in the VPR-1 and VPR-2 professional one-inch helical recorders. Some of the engineering advances required for the system are discussed, including flexure longevity, flexure stability in a dynamic environment, and maintenance of head-to-tape contact at large deflections.