JPH02105369A - Digital data recording/reproducing device - Google Patents

Abstract

PURPOSE:To decrease the recorded data quantity and to improve the recording efficiency by taking out only the common address signals among those address signals recorded in each frame on the same track and recording those taken-out address signals in response to the record data on a preamble part. CONSTITUTION:A data pattern of a preamble part is changed for each track for identification of these tracks, and the address signals common to each other on the same track are replaced with the data patterns on each track. These data patterns are recorded at the preamble part. At reproduction the tracks can be identified by the counters 20-1 20-N from the patterns of the record signals of the preamble part which are reproduced by the demodulation circuits 8-1 8-N. Thus it is possible to replace the same signals of the picture frame No, the field No, the track No, etc., recorded at the address part of a digital video tape recorder, etc., with the preamble part. Then the recording efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a digital data recording/reproducing device (for example, a digital VTR).

(b) Prior Art First, signal processing of a digital VTR will be briefly explained. The video signal (analog) and audio signal (analog) to be recorded are sampled and converted into digital signals. Each converted video and audio data is configured into one block for every certain number of samples. After forming blocks in this manner, error detection or error correction codes are generated for each block. After that, the correction block is divided into small blocks, and a digital synchronization signal is added to the beginning of the small block, and an address signal indicating the data position and an information code (called ID) regarding the recorded data are added to the rear of the small block. and is configured into the frame shown in FIG. In this way, the data organized into frames are recorded on one track (shown in FIG. 8) of the magnetic tape by a rotating magnetic head in a 7-track format as shown in FIG.

By the way, when demodulating a digital signal from a signal recorded on a magnetic tape, it is necessary to reproduce a clock that is phase-synchronized with the reproduced signal and perform signal processing using this clock. In the case of a magnetic recording/reproducing system using a rotating head, the signal from the reproducing head changes at the beginning of the tape.
It is necessary to generate a clock that is phase synchronized with the signal from this reproducing head. For this reason, a preamble section shown in FIGS. 7 and 8 is provided. Using the reproduced signal from this preamplifier section, a clock that is phase-synchronized with the reproduced signal is usually reproduced in a PLL (phase-locked loop) circuit. The length of this preamble section is recorded for a predetermined period of time with sufficient margin in consideration of the pull-in time of the PLL circuit and rotational jitter of the rotary head. At this time, the recorded signal of the preamble section is generally recorded as a signal of a constant frequency (Japanese Patent Application Laid-Open No. 1983-1989).
(See Publication No. 117 (G11BS109)).

Furthermore, in a conventional analog VTR that records a video signal by FM modulating it, the video signal for one field is recorded on one track. On the other hand, digital VTRs sample video signals and record them as digital signals, so
Since there is a large amount of data to be recorded, it is common to divide and record data for one field into a plurality of tracks (N tracks) as shown in FIG. For this reason, each track has information bits for identifying which part of the field screen the data belongs to, that is, the track number, and if necessary, information such as field number of the image and frame Nα, etc.
A method of recording in the address signal section is often used.

In the address signal section, a digital frame N.alpha. in which digital signals are formed into frames and counted up in units of one track is recorded.

These address signals generally have the configuration shown in FIG. 9, and may be recorded with an error detection bit added thereto as shown in FIG. Among these, the image f-image frame Nα,
Since the same signal is recorded in each digital frame on the same track, field numbers, track numbers, etc. are useless in terms of recording efficiency of information data.

(c) Problems to be Solved by the Invention The present invention extracts only common address information from among the address information recorded in each digital frame on the same track, and stores this information in one location on the same track. This aims to reduce the amount of information data recorded on one track and improve the recording efficiency of information data.

(d) Means for Solving the Problems The present invention is such that address signals common to the same track can be identified by data recorded in the preamble section. In other words, the modulated signal for each track has a different frequency such as f, 2f, 3f, etc., or the data recording pattern, for example, the data bit length is set to T (time length for one focus). ), then T
, 2T repetition, 2T, 3T repetition, etc. can be realized by changing the pattern of recording data for each track.

(E) Effects According to the present invention, by replacing the common address signal on the same track with the data pattern of the preamble section of each track, the amount of recorded information of the digital VTR can be reduced.
That is, the recording frequency can be lowered. Therefore, as the S/H of the reproduced signal is improved, the error rate of the reproduced data can be lowered, so that more reliable data can be reproduced.

(f) Embodiment Next, an embodiment of the present invention will be described using FIGS. 1 to 5. FIG. 1 is a circuit block diagram of the recording system. Analog audio signal from input terminal (1-1), input terminal (1-1)
-2), the analog video signal is input from A/
It is converted into a digital signal by D conversion (2-1) (2-2). The converted digital signal is recorded in the RAM (4) by the recording control circuit (3). R.A.
The digital signal recorded in M(4) is read out to the error correction code generation circuit (5) under the control of the recording control circuit (3) while taking into consideration the inter-band, and after the correction code is generated. It is also stored in RAM (4). After the error correction code is generated, data is read out from the RAM (4) under the control of the recording control circuit (3), distributed to N channels, and sent to frame synthesis circuits (10-1) to (1), respectively.
0=N). Here, the synchronization signal generation circuit (
The frame synchronization signal generated in step 6), the address signal indicating the digital frame number generated in the address signal generation circuit (7), the information code regarding the recording signal generated in the ID generation circuit (8), and the preamble/postamble. Distinguishable data of each track generated by the signal generation circuit (9) is output as a preamble/postamble signal and combined.

By the way, the signal generated by the preamble/postamble signal generation circuit (9) is composed of different data for each track and output in a field, frame, or multiple frame period so that the data of each track can be identified. Ru. However, since this data is used for identification at least in the preamble signal section, it is not necessary to use the same data as the postamble signal.

The frame synthesis circuits (], o-1) to (10-N) output each channel as shown in FIG. 7, and each frame has the structure shown in FIG. 6. After this, the modulation circuit (11
-1) to (11-N), and is modulated by recording amplifiers (1, 2).
-1) to (12-N), and the rotary transformer (13
) to (14,
-N) on the magnetic tape (15)''- as shown in FIG.

Here, the modulation method is NRZI, 2-channel recording,
If it is necessary to identify the tracks for one field in divided recording of four tracks per field, it is sufficient to prepare four types of data as preamble signal data. At this time, as an example, FIG.
If the four types of data (d) are used (the data indicated by "1, 0" shown in the figure), the recording signal after NRZ I modulation will have the waveform shown in FIG. 4.

Regarding the signal processing during reproduction, only the signal processing of the preamble section according to the present invention will be explained using FIG. 2, and the explanation of the video and audio signal processing will be omitted.

Signals recorded on the magnetic tape (15) are read out by magnetic heads (14-1) to (14-N), and transmitted to respective reproduction amplifiers (6-1) via rotary transformers (13).
) to (16-N). Playback amplifier (16-
The reproduced signals amplified in 1) to (16-N) are subjected to waveform equalization processing in waveform equalization circuits (1, 7-1) to (17-N), respectively, and then sent to demodulation circuits (18-]). ~(18-N) and the clock recovery circuit (19-]) ~(19-N). The clock regeneration circuits (19-1,) to (19-N) regenerate a clock phase-synchronized with the regenerated signal. Using this recovered clock, the demodulation circuit (18-1) ~
At (18-N), the original data will be reproduced.

4 (a) to (d) are the recorded signals of the preamble section recorded on four tracks, and FIG. 5 (a) to (d)
shows each signal when the modulated signals of FIGS. 4(a) to 4(d) are demodulated. Therefore, the demodulated signal (
Tracks can be easily identified by inputting the numbers (a) to (d) in FIGS. 5A to 5D to the counter circuits (20-1) to (20-N) for a certain period of time and counting them. The operating principle at this time will be explained.

Figure 3 (a) shows the head switching signal and the signal regeneration period of each trunk, from "High" to "Low".
Alternatively, it indicates that the playback track is switched at the time of transition from "Low" to "High".

At this time, the edge portion of the hand switching signal is taken out, and this signal is used to control the counter circuits (20-1,) to (20-\
). FIG. 3(b) shows a signal input to the enable terminal of the counter so that the counter circuits (2(1-1) to (20-N) can be counted for a fixed period of time. -1)～
(23N). This enable signal is sent to the counter circuit (20
-1,) to (20-N) are enabled. Therefore, in FIG. 5(a), the count number is basically "0". If the count number in (b) is M, the count number in (C) is 273M, and the count number in (d) is 18M. . Therefore, it is possible to sufficiently identify track sentences by counting within a suitable time. This counter (
The outputs of each of 20-1) to (20-N) are input to trunk selection determination circuits (21-1) to (21-N), which determine the track Nα based on a preset count threshold. , will be decided.

The track Nα determined by the track identification circuits (21-1) to (21-N) is sent to the playback control circuit (24).
The track's data will be processed.

(1) Effects of the Invention According to the present invention, only the common address signals are extracted from among the address signals recorded in each frame of the same track, and are recorded in correspondence with the recorded data of the preamble section. This makes it possible to reduce the amount of recorded data. Accordingly, since the error rate of the reproduced signal can be lowered accordingly, highly reliable data can be reproduced.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the recording circuit of the embodiment, Fig. 2 is a block diagram showing the reproducing circuit as well, Figs. 3, 4, and 5 are waveform diagrams showing the operation, and Fig. 6 is a digital VTR. FIG. 7 is an explanatory diagram showing a track recording format, FIG. 8 is an explanatory diagram of a tape format, and FIG. 9 is an explanatory diagram of an address signal section. (9)...Preamble/postamble signal generation circuit

Claims (1)

[Claims] (1) In a digital data recording and reproducing device that records a plurality of tracks on a magnetic tape using a rotating magnetic head by providing a clock pull-in signal during playback before digital data, a different signal is used for each track as the clock pull-in signal. A digital data recording and reproducing device characterized in that it is used to identify tracks during playback.