JPS58105416A - Method and circuit for recording time information on length-wise track of magnetic tape - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and a circuit arrangement for recording time information on longitudinal tracks of a magnetic tape. Magazine 6 Journal of the Varnish, M, B, Qi, E”, LG) 73
．． From June, No. 82, Pages 482-4QL It is known to record a binary encoded data signal representing each tape position on the longitudinal track of a video-magnetic tape. These data signals are recorded as 80-bit data words in the form of consecutive pulses and are used to display hours, minutes,
Contains usage-related information such as seconds display, video number display, and synchronization information.

Time information and usage-related information then require 64 bits, and the synchronization word requires the remaining 16 bits. In order to code this data signal, the E, B, U, R document technology 3097 introduced the Bi-Phase-Mark code, which was also standardized by the European Broadcast Union.
Code ), independent PtsukkoP is being implemented all over the world.

In magnetic tape apparatuses for recording television signals, in particular color television signals, synchronization pulses are generally recorded on the longitudinal traverse of the magnetic tape, which are extracted by rotation of a spatula PP ram. In addition to this, alternating pulses are generated in the detection device once per rotation of the spatula PP ram.

During regeneration, this pulse train is used for phase synchronization of the Hella PP ram. That is, in the same manner as during recording, the pulse generated during reproduction is compared with the control track pulse extracted from the magnetic data. In previously used lateral track recorders, Hella PP rams provided 250 Hz for recording black and white television signals and color television signals according to the AA standard. On the other hand, television signal recording according to the American black and white standard or NTS
Hera P when recording color television signals according to the O standard.
The rotation speed of the P ram was 240 r, p, m. For that purpose the control track is 250111z- in the first case.
in the second case the pulse had an average frequency of 2
Recorded at 40 Hz.

8 of the data signal expressed as a time code P as described above.
In choosing the length of a 0-bit word, it has been standard to: That is, a bit repetition frequency of 2000 (80 bits x 25 frames) when recording video according to the European television standard, or a bit repetition frequency of 24.00 (80 bits x 30 frames) when recording a television signal according to the American and Japanese standards. Unwanted interference of signals recorded in parallel longitudinal tracks was avoided because the frequencies were in a simple ratio of aCt or toot to the respective selected control track frequencies. The above-mentioned document already indicates the possibility of using time code information instead of control trunks for server yg purposes.

Eventually, a recording method was implemented in which magnetic tape was recorded on successive track sections running diagonally along the edges (diagonal track-recording method). This method rotates at a different rotational speed than in the transverse track magnetic tape recording devices which were used exclusively at the time of the determination of the Hellaph+Fram Time Coorr standard. Therefore, the control track is 240
Hz or 250 Elz, the simple numerical relationship between the control track frequency e and the bit repetition frequency that was originally sought to be obtained is lost.

Effects of the Invention The method according to the invention having the features of claim 1 has the following advantages over it. That is, by appropriately selecting the Co-P word format, the pit repetition frequency will be an integer multiple of the control track frequency.

Another advantage is that the information of two longitudinal tracks is combined into one track.

The method indicated in the implementation section provides advantageous embodiments of the method according to claim 1. Particularly advantageous is the cut mark (Sch
nittmark). Odd-even test bits and check bits can likewise be provided in an advantageous manner. A further advantage is that the circuit arrangement implementing the method of the invention can be essentially the same for the two standards. A further advantage is that the clock selection for time code 1 and control track can be performed in a common circuit.

DESCRIPTION OF EMBODIMENTS Embodiments of the circuit device of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a block diagram of a circuit arrangement for extracting the bit repetition frequency and the control track-fundamental frequency during the processing of a PAL color television signal.

Phase slot circuit (hereinafter referred to as PLL circuit) 2
Horizontal synchronization with a horizontal scanning frequency of 15625 Hz to generate the necessary control track frequency and pit repetition frequency for the time code P when recording a PAL code converted color television signal at the first input terminal 1 of the A signal is provided. Since the coefficient is multiplied in PLL circuit 2, 62500 t(
A pulse train with a clock frequency of z results. This clock frequency is supplied to the second input terminal of the PLL circuit as a horizontal scanning frequency clock in the first frequency divider circuit with a frequency division coefficient, so that the phase lock between the output side signal and the input side signal is maintained at the input side. Occurs on side 1.

The output clock pulse train of 6250011z of the PLL circuit 2 is divided into a desired pit repetition frequency 2 in a second frequency divider circuit 5 having a frequency division coefficient of 25 to generate a time-to-one word.
The frequency is divided to 500 Hz. The reset input R5 of the frequency divider circuit 5 and the reset input R3 of the frequency divider circuit 3 are supplied with signals at an interval of 2v (frame frequency) = 25 Hz, thereby simultaneously being combined with the vertical synchronization signal. Resetting the frequency divider 5 indicates that every 100 oscillations in the 2500H2 pulse train a new time-to-1 word begins, which time-to-1 word therefore has a length of 100 bits. The bit repetition frequency of 2500 Hz is divided in a third divider circuit with a division factor of 8 to the control track frequency of 3 12', .5 H2 desired for a given recording device. A 4V synchronizing pulse of 12.5 Hz is supplied to the reset input side R6 of the frequency divider circuit 6,
This ξ pulse is thereby combined with the 312.5 Hz control track clock. From the output signal of the frequency dividing circuit 5, a time code r which is numerically converted into a code P by modulation is obtained. In this case, the original time-to-word is 80 bits long according to the standard, while the pits 81st to 1oo can be used freely. Especially number 81,
~A check pit and a checker P can be placed in the 100th pit (4v cut mark (Schneidemarke) and 8v color frame pulse in the PAL system).

Because of the constant integer relationship between the control track frequency and the bit repetition frequency, control track information having time to P can be collectively recorded on longitudinal tracks provided on the magnetic tape. The freely available recording surface and utilization on the magnetic tape is thereby improved. When combining the time-to-r and control tracks into a common track on the tape, the output of frequency divider circuit 6 is used only as a reproduction reference for the reproduced control tracks.

The circuit arrangement of FIG. 2 completely corresponds in structure and operation to the circuit of FIG.
1 5750 corresponding to the horizontal scanning frequency in C method
A frequency of Hz is provided.

A fundamental frequency of 630 o nz is generated on the side, which fundamental frequency is divided in the divider circuit 25 to a bit repetition fundamental frequency of 2520 Hz. Reset input side R23 of frequency divider circuit 23 and reset input side R of frequency divider circuit 25
25 is supplied with a 2v-synchronization signal corresponding to the frame frequency of 3011z. This results in a word length at time P of 2520:30=84 pits.

The bit repetition fundamental frequency of 2520 Hz is divided by a division factor of 8.
The frequency is divided into a control track frequency of 315 Hz by a frequency dividing circuit 26 having a frequency of 315 Hz. Since the word length f'a in the feed to P is 4 pits, the standard of 80 pits is required for each word at each hour. The Φ pit in each word as a length can be used for special purposes, for example to provide cut marks (IJTsO system: 2v cutmark and 4v color frame, -munozorus).

In order to reproduce data recorded in a single longitudinal direction of a magnetic tape 32 in FIG. 3, this data is scanned by a magnetic spatula P31 and converted into an electrical signal by a signal coil 33. After a corresponding amplification in an amplifier 34, these data are fed to a pulse shaping stage 35,
At the output 36 of this pulse shaping stage, a time-to-P ripple occurs. On the other hand, after demodulation, at the output 37 the data contained in the recorded tracks are retrieved for use. The clock on line 36 is applied to the clock input of shift register 38. The shift register includes memory cells that store pits that are present at time intervals of at least one telepy frame. The data on 1s37 is shifted into shift register 38 by a clock at the pit clock frequency on line 36. At the first parallel output of the shift register 38 there is a synchronization word detector 39 which, in the presence of a synchronization word, sends an output signal to the reset input of the frequency divider circuit 40, thereby causing the NO'? Luss molding ff
The clock train on the clock output side 36 of 35 is converted into a clock train of 312.5 Hz (in the case of PAL system) in accordance with the division coefficient 8. When a sync word occurs in the time-to-r data signal and is reset, a constant combination with the time-to-two word (2V-video) is performed. The -I signal on the output side of the synchronization word detection circuit 3Q is the shift register 38.
Memory 4 is connected to the parallel data output side of
It is also supplied to the set input side of 1. When a pulse occurs on the set input side, the contents of the shift register 38 are transferred to the buffer memory 41. The output, indicated in brackets 42, then contains the time-to-two words according to the standard;
On the other hand, the output side shown in parentheses 43 can include cut marks, check pits, etc. The A pulse train with the control track clock from the output side of the frequency divider circuit 40 is supplied to one input side of the phase comparator circuit 44, and the second input terminal of the phase comparator circuit 44 is supplied with the control track clock from the output side of the frequency divider circuit 40. The standard is 312°5Hz (31511z) in several states.
A reference-control signal from a clock source 45 is provided.

Depending on the difference between the control track noggles of the reference signal and the signal extracted from the magnetic tape and processed, the phase comparator circuit 44 can be used in a known manner for the synchronization adjustment of the magnetic tape drive. Generates an output signal.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the circuit arrangement for obtaining the pit repetition frequency and the control track-fundamental frequency when processing a PAL color television signal, and Fig. 2 shows the NTS (! system and PAL
FIG. 3 is a block diagram of a circuit arrangement with frequencies occurring during the processing of M-1 color television signals for reproducing data information, cut marks and control track clocks from recorded time-to-P format; A block diagram of the device is shown. 2.22... Phase lock loop circuit, 3.5.6
・23・25・26・40... Frequency divider circuit, 31...
Magnetic spatula P132...magnetic tape, 33...signal fill, 34...amplifier, 35...zorus forming stage,
38... Shift register, 39... Synchronization word detector,
Daytime 1...] buffer ~ memory, 44... phase comparator circuit, 45... reference-rep check source

Claims (1)

[Claims] 1. A method for recording time information on a longitudinal track of a magnetic tape, characterized in that a time-to-one word clock is selected to be larger than a time-to-two word length. How to record time information. 2. A method for recording time information on a longitudinal track of a magnetic tape according to claim 1, wherein the time low r-base clock and the control track frequency have a simple integer relationship. 3. A method for recording time information on a longitudinal track of a magnetic tape according to claim 1, in which a check pit or a check y-f is inserted at a bit position exceeding the length of one time-to-word. . 4. A method for recording time information on a longitudinal track of a magnetic tape as claimed in claim 1, wherein cut marks are placed in bits that exceed the length of a word in a time-coded word. 6. In order to reproduce the information contained in the longitudinal tracks of the magnetic tape, all clock parts entered into the shift register (38) during reproduction are passed through the synchronization word-detector (38).
9), and when a synchronization word occurs within time to P, the frequency divider circuit (40) is reset, and this frequency divider circuit is taken out from the magnetic tape (32) and generated from the A pulse forming stage (35). Time call converts the basic clock into a control clock and simultaneously records the data contained in the shift register (38) at this point in time. A method for reproducing time information on a longitudinal track of a magnetic tape according to claim 1, wherein the time information is transferred to a magnetic tape. 6. In a device for recording time information on a longitudinal track of a magnetic tape, pulses at the horizontal scanning frequency of each television standard are supplied to the first input side of the phase-locked loop circuit (2), and the horizontal scanning frequency time information in a longitudinal track of a magnetic tape characterized in that the pulses are multiplied to generate a fundamental frequency, this fundamental frequency is divided once to obtain a bit repetition frequency, and divided again to obtain a control track frequency; A circuit device that records. 7. 2V on the reset input side of the first frequency divider circuit (5, 25)
The second frequency divider circuit (6, 2
7. A circuit device for recording time information on a longitudinal track of a magnetic tape according to claim 6, wherein a pulse train of 47 frequencies is supplied to the reset input side of the circuit device. 8. Pulse shaping stage (35) for transforming the information extracted from the magnetic tape (32) by the magnetic spatula r (31) into time information - basic clock - pulse train (36) and data train (37). , a shift register (38L) to which the clock input side is supplied with the time code P-clock and the data input side is supplied with the data contained in the time code P-track.
A synchronization word detector (39) for detecting the complete time code P clock part, a buffer memory (4) for transferring the information contained in the complete or lock part.
1) and a frequency dividing circuit (40) for obtaining a control track clock from a time code r-clock.