Speicher- und Lesesystem fuer blockweise gespeicherte Informationen

• Main Authors: HOOPER,CLIVE, JOHN ROGERS,BERNARD, ALLEN KERR,JAMES
• Format: Patent
• Language: German
• Published: 28.09.1972
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; PICTORIAL COMMUNICATION, e.g. TELEVISION

1379905 EVR recording system RANK ORGANISATION Ltd 8 March 1972 [15 March 1971] 6867/71 Heading H4F In a storage and retrieval system of the type described in Specification 1,379,904, e.g. an EVR system, apparent changes in the picture height due to variations in drive speed of the film are reduced by deriving control signals from signals representative of the phase relationship between field pulses reproduced from the film on line 22 and a periodic reference signal on line 10, e.g. a 50 Hz mains signal. This phase relationship is detected in phase detector 30 which gives a short duration output during the field blanking period which represents in polarity and magnitude the extent of any phase error representative of film speed error. This short duration output is stored, e.g. in a box-car lengthener 32, and the resulting signal in addition to being applied as additional field deflection to the flying spot scanner tube of the film reader as in the above referred to Specification to vary the scanning raster position from frame to frame, is also differentiated, 34, 36, and fed via a temporary store 41 similar to store 32 to control a constant current source 38 whose output is connected together with the output of the field rate circuit 40 (controlled by the reference mains signal) to the scan circuit 16 which effects the field scanning of the flying spot scanner. The effect is to vary the field sync. pulse generation and thereby correct the picture height. Field sync pulses for the EVR output are derived, 18, from the reference mains signal, and conventional film transport drive synchronization is effected by phase comparison, 20, of the retrieved field pulses and the reference signal.