Method and device for controlling the phase relation between a head drum and tape feed system of a magnetic tape recording device

Method for controlling the phase relation between a head drum and tape feed system of a magnetic tape recording device for digital picture information wherein the digital picture data is subdivided in blocks having assigned a pointer value each and wherein the pointer values define which part of the picture the block of picture data represents, characterized by the steps of:

• storing in corresponding locations in a measured value store the recognized pointer values at the beginning or ending of correctly read data areas;
• determining the distance between the pointer values of consecutively correctly read data regions;
• and
• determining a phase correction value for the control of the phase relation between head drum and tape feed system based on the distance between pointer value regions.

Method for controlling the phase relation between a head drum and tape feed system of a magnetic tape recording device for digital picture information wherein the digital picture data is subdivided in blocks having assigned a pointer value each and wherein the pointer values define which part of the picture the block of picture data represents wherein for selected operation modes additional picture data is stored in the predetermined data areas of the tape which will be read out in the selected operation modes, characterized by the steps of:

• storing in corresponding locations in a measured value store the recognized pointer values at the beginning or ending of correctly read data areas;
• determining the distance between the pointer values of consecutive correctly read data regions;
• and
• determining a phase correction value for the control of the phase relation between head drum and tape feed system based on the distance between pointer regions.

Device for controlling the phase relation between a head drum and tape feed system of a magnetic recording device for digital picture information comprising:

• a detector for pointer values (33) recorded on tape which define which part of the picture the corresponding read picture data represents,
• a measured value store (35) for storing an information corresponding to a detected pointer value which represents the amount of detections of the pointer value in an assigned location,
• a counter (36) for incrementing or decrementing the assigned location in the measured value store (35) each time the corresponding pointer value has been detected,
• a calculating unit (40) for determining a
• a calculation unit for determining the distance between pointer value units regions which have been reproduced more often than regions in-between, thereby taking into account the difference in reproducing frequency between the more often reproduced regions and the more seldom reproduced regions according to the measured value stored entries, and for determining a phase correction value for the control of the phase relation between head drum and tape feed system based on the distance between pointer value regions;
• and
• a servo control unit for generating the phase correction signal and applying it to the tape feed system.