摘要:
In the case of various recording systems based on the helical-scan method for magnetic tapes, a pilot-tone principle is used for tracking control, generally using two pilot tones which are recorded on the helical tracks respectively in series of four: pilot tone F1, no pilot tone, pilot tone F2, no pilot tone. Known methods for determining the pilot-tone amplitudes use narrow-banded band filters, a control signal being generated by forming the difference between the amplitudes. On account of the weak pilot tones, this requires very narrow-banded filters with good dynamic properties.According to the invention, a quadrature mixing has the effect of converting the two pilot tones into the baseband, whereby the filtering is performed in the low-pass range and a control signal can be derived from the difference between the pilot-tone amplitudes thus determined.
摘要:
The invention relates to a method for recording longitudinal track bundles on an information medium. The method involves recording tracking information in special tracks in said track bundles. The special tracks are contiguous between each other. When recording a new track bundle a recording and/or reading head may be positioned using tracking information contained in special tracks of a previously recorded track bundle. Several examples of patterns used for coding tracking information in the special tracks we described.
摘要:
The invention relates to a tracking device in which a position of a coil driven actuator is determined using a sensor coil. A reference signal 12 having a determined voltage and frequency is fed to a driven coil. A position of the coil driven actuator is proportional to a distance between the driving coil and the sensor coil. The sensor coil produces an alternating voltage induced by an alternating magnetic field emitted by the driving coil. The alternating voltage is used to determine the position of the actuator.
摘要:
The invention relates to a device for positioning a first element relatively to a second element. The device according to the invention uses lifting means comprising a cam element and actuator means to actuate the cam element. The cam element has a plurality of contiguously arranged sectors with machined edges belonging to first and second interleaved groups. The machined edges are shaped such that a response of the lifting means to the actuator means has different values for sectors of said first and second group thereby providing alternately a coarse positioning and a fine positioning. The device may for example be used to position a multitrack magnetic tape and a magnetic writing/reading head relatively to each other.
摘要:
It is known in the case of digital helical track recording and replay apparatuses for audio, video and general data to be recorded for pilot tones to be interleaved in the data tracks, for tracking. The interleaving can be carried out simultaneously with the data by frequency decoupling (a) or by superimposition (b). The invention is based on the object of providing a helical track recording and replay system which carries out tracking in a simple manner. According to the invention, the ATF signal is obtained in a filter module, which also carries out the rectification of the filtered-out pilot tones. The two DC voltage levels are interrogated and processed in the servo microcontroller, with A/D converters. Coupled to the rotation of the head drum, pulses are produced by the servo system which switch the ATF conditioning over between direct operation and tracking operation, so that evaluation is achieved by the microcontroller during the fast ATF burst phase.