JPS58166558A - Detection control system of magnetic tape speed - Google Patents

Abstract

PURPOSE:To detect and control a tape feed speed and to stop a tape start end at a specific position, by recording an equal-interval pulse signal in an unrecorded area on a magnetic tape, and reproducing the pulse signal. CONSTITUTION:Prior to normal data recording or reproduction after tape loading, the tape is run backward temporarily, and the equal-interval pulse signal is recorded on the tape by a writing head 2. After the recording, the tape is run forward and positioned again at a loading point. For tape take-up operation, a file reel 3 is driven to run the tape backward. At this time, the previously recorded equal-interval pulse signal is read by a reading head 4, and the tape feed speed is calculated from time intervals of the appearance of a pulse output. The deviation of the speed from a specific speed is fed back to a take-up reel motor to perform speed control.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention The present invention relates to a magnetic tape speed detection and control method, and is particularly suitable for speed detection in non-recorded areas on a magnetic tape, and is a method for controlling the magnetic tape speed by recording and reproducing equally spaced pulses. Regarding detection and control.

Conventional technology The conventional method for detecting tape winding speed was to provide a light reflective marker at one location on the circumference of the tape supply reel (machine reel) and detect the speed based on the reflected signal each time the reel rotated. Therefore, the measurement accuracy was poor, and the speed of the tape itself was not measured.

OBJECT OF THE INVENTION An object of the present invention is to record fh
The object of the present invention is to provide a method for detecting and controlling the chip feed speed by recording and reproducing pulse signals, thereby stopping the tape starting end at a predetermined position.

Conventional tape feeding speed measurement detects the number of rotations of the tape reel. Since the tape feeding speed is determined by the rotation speed and the tape winding radius, this system requires the winding radius to be constant or an additional function for correction if it fluctuates. The present invention directly measures the speed of the tape itself using a simple method in order to eliminate the drawbacks of the conventional method.

Embodiment of the Invention An embodiment of the present invention will be explained below with reference to FIG. 1.2.3. Figure 1 shows an outline of the magnetic tape device Chibuto 2-IV system and the recording format on the tape at this time. This figure shows the state in which the tape has been loaded. During normal data recording and playback, the machine reel 1 moves in the forward direction and winds the tape. The tape is then run in the opposite direction. In the present invention, after loading the tape and prior to normal data alignment reproduction, the tape is once run in the reverse direction and pulse signals at equal intervals are recorded on the tape by the write head 2.

After recording, the tape runs forward and is repositioned at the load point. The equally spaced pulses in the non-recording area on the tape are used to detect the tape feeding speed during the subsequent tape winding operation. In the tape winding operation, the file reel 3 is driven to run the tape in the opposite direction. At this time, the previously recorded equally spaced pulse signals are read out by the read head 4, and the tape feeding speed is calculated based on the time interval at which the pulse outputs appear.

FIG. 2 illustrates tape speed detection and an embodiment using the same in terms of changes over time.

When winding the tape, the recorded equally spaced pulses 5 are reproduced by the read head 4 in the manner shown in the figure.

This signal passes through a delay device to the R8T input of the speed detection counter and is directly input to the trigger input of the latch. A predetermined speed is set in the preset input of the counter, and compared with the head reproduction pulse interval measured by the clock input. The deviation between the set speed and the measured speed is stored in a latch as a count. This latch output is updated every pulse of the head reproduction output. A latch output and a fixed bias for a predetermined speed set in advance are input to the DAC input, and the motor drive amplifier is driven depending on the output of , and the tape feeding speed is controlled.

Effects of the Invention According to the present invention, the mechanism of the current magnetic tape device can be improved.
1, and the magnetic tape feeding speed can be detected without adding any dedicated parts, which has the effect of easily realizing highly accurate magnetic tape speed control.

[Brief explanation of drawings]

Fig. 1 is a schematic explanatory front view of the running drive system of a magnetic tape drive device, and a diagram of the origin of the tape with load point positions. Fig. 2 is a block diagram of tape speed detection and control by equally spaced pulse signal reproduction. 3 are time charts showing temporal changes in the operation shown in FIG. 2. 1...Machine reel 2.Light head 5...
・File reel 4, read head 5...
Equally spaced pulse signal agent Patent attorney Bo 1) Ri, Shin・1

Claims (1)

[Claims] t In a magnetic tape device that has a recording head and a playback head and has automatic loading and rewinding functions for magnetic tape media, evenly spaced pulse signals are recorded between the BOT marker and the beginning of the tape after loading the tape, and when rewinding the tape, A magnetic tape speed detection and control system characterized by having a function of detecting the tape rewinding speed by reproducing this signal, and a function of feeding back the deviation between the detected speed and the specified speed to a take-up reel motor to control the speed.