JPH02154386A - Digital tape recorder - Google Patents

Abstract

PURPOSE:To edit a digital signal even when a time code signal is intermittently recorded by recording the time code signal formed based on a regenerative time code signal from a precedent reproducing head after delaying a time equivalent to a tape path between the precedent reproducing head and a recording head. CONSTITUTION:The subject recorder possesses the precedent reproducing head 10, a time code signal generating circuit 101 for forming the time code signal to be supplied to the recording head based on the regenerative time code signal from this precedent reproducing head and delay circuits 106 and 107 for compensating the time lag equivalent to the tape path between the precedent reproducing head and the recording head. Consequently, the original time code signal recorded intermittently is modified to be a continuous time code signal in the same phase, which is then recorded again by a digital signal and an inline. By this method, even when the time code signal is intermittently recorded, the digital signal can be edited.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a digital tape recorder suitable for editing using time codes.

[Summary of the invention]

In a digital tape recorder that records digital signals and time code signals, the present invention forms a time code signal based on a reproduced time code signal from a preceding playback head, and transmits this time code signal between the preceding playback head and the recording head. By recording with a predetermined time delay corresponding to the tape bus between the two, the original time code signal recorded discontinuously is corrected to a continuous time code signal with the same phase, and is recorded in-line with the digital signal. It was designed to be re-recorded.

[Conventional technology]

Traditionally, multi-track digital audio tape recorders equipped with fixed magnetic heads have been used as professional digital recorders used in recording studios and other facilities.
Audio 5tationary head recorders) are known.

This DASH recorder has a sampling frequency of 48k.
It records 16-bit digital audio signals at Hz or 44.1 kHz, and can cover 2 to 48 channels depending on the combination of tape width, track density, and tape speed. For example, 172 inches (12,7
mm) wide and normal density tape at 30 inches/second (76c
m/s) and can record 24 tracks of digital audio signals.

As shown in Figure 3, the DASH format has four auxiliary tracks AUX1 at each edge and center of the tape.
~AUX4 are provided, and 12 digital recording tracks DTI~DT12, DT13~D are provided in between.
T24 is placed.

In the case of recording of 48 channels, as shown by broken lines in the figure, the 24 tracks corresponding to channels 25 to 48 are divided into two groups and placed adjacent to DT1 to DT12 and DT13 to DT24, respectively. Track density doubles. For channels 1 to 24, full compatibility in track arrangement is achieved between the double density format and the normal density format.

By the way, when recording music using the multi-track method, for example, only the rhythm section is recorded first, and while this is played back, strings, plus section, vocals, etc. can be recorded individually on different tracks, or played back sequentially. It is common to record other sections in addition to the sound.

For this reason, so-called "cueing" is used to determine the starting point (editing point) of recording or playback on the tape for playback of an already recorded section or editing such as partial re-recording.
(cue finished ° blowfish) is required.

Therefore, in the DASH format, auxiliary tracks AUX 1 and AUX 4 are provided on both sides of the tape, and the same content as recorded on any digital track is recorded on the auxiliary track AU.
Analog signals are synchronously recorded on XI and AUX4, and this analog signal (cue signal) can be used to easily cue.

In this case, as disclosed in Japanese Patent Application Laid-open No. 57-105813, a digital signal playback head is disposed upstream of the tape at a predetermined distance du with respect to the cue signal recording and playback head, and It is preferable that the digital signal recording head is disposed downstream of the tape at a predetermined distance dd.

The predetermined distances du and dd are respectively determined by the digital signal processing time in the reproducing circuit system and the recording circuit system and the running speed Vt of the magnetic tape.

According to the distributed arrangement of the heads as described above, when recording on a digital track, the signal processing time τ5hod for PCM modulation etc. is used, and when reproducing from the digital track, the signal processing time rde■ for PCM demodulation etc. is used. , the time difference that occurs between the digital signal and the corresponding cue signal is compensated for, the digital signal and the cue signal are recorded aligned in the width direction of the tape, in-line property is maintained, and the digital signal and the cue signal are recorded from the digital track and the auxiliary track. Mutually synchronized reproduction signals can be obtained.

Furthermore, in the ASH format, a time code is recorded on one of the auxiliary tracks AUX2 in the center of the tape, and this time code can also be used to determine the editing point.

This time code is based on the American Society of Motion Picture and Television Engineers (
Society of Motion Picture
and Television Engineers)
and the European Broadcasting Union (European Broadcasting Union).
This is a standard recommended by the Casting Union, and an address consisting of an hour, one minute, and a second and a frame is composed of 80 bits. Modulation method is BI-PHASE MAR
This is the K method.

Note that a control B signal for servo-controlling the running of the tape is recorded on the other auxiliary track AUX3 at the center of the tape.

[Problem to be solved by the invention]

With a magnetic tape on which a time code as described above is recorded, the time code can be played back and synchronous recording or other tape editing can be performed based on this time code.

However, if the recording state of the time code is poor due to dropouts or the like, there is a problem that tape editing using the time code cannot be performed. Also, if you accidentally remove the time code during recording and the time code is interrupted, or if you record a different time code over the recorded time code, the same problem can occur. A problem arises.

To this point, an object of the present invention is to provide a digital tape recorder that is capable of editing digital signals even when time code signals are recorded discontinuously.

[Means to solve the problem]

The present invention provides a digital tape recorder in which digital signals and time code signals are recorded on a magnetic tape T via a recording head (20). A time code signal generation circuit (101) that forms a time code signal to be supplied to the recording head based on the code signal, and a delay circuit (101) that compensates for the time delay corresponding to the tape path between the advance playback head and the recording head. 106) , (
107).

[Effect]

According to this invention, the original time code signal recorded discontinuously is corrected to a continuous time code signal having the same phase as the original time code signal, and is re-recorded in-line with the digital signal.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a digital tape recorder according to the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows the overall structure of an embodiment of the present invention, and FIG. 2 shows the structure of its main parts.

In FIG. 1, (10) is a composite playback head,
A digital playback head (as shown in FIG. 3 above) corresponding to a plurality of digital recording tracks DT on a magnetic tape T
11), and playback heads (12) and (13) corresponding to auxiliary tracks AUX 1 and AUX 2, respectively. (20) is a composite recording head, and a digital recording head (21) corresponding to the digital recording track DT.
and recording heads (22) and (23) corresponding to auxiliary tracks AUXI and AUX2, respectively.

Note that both composite heads (10) and (20) are arranged at a predetermined distance (du+dd) as disclosed in the above-mentioned Japanese Patent Laid-Open Publication No. 57-105813. Further, the reference line Lref indicates the arrangement position of the analog recording/reproducing head in the digital tape recorder described in the publication.

(31) is a PCM decoder, to which the output of the digital playback head (11) is supplied via an amplifier (32);
The output of the decoder (31) is led out to an analog signal output terminal (34) via a DA converter (33). Signal processing in the decoder (31) and DA converter (33) requires time τde-.

(41) is a PCM encoder, and input terminal (42
) is supplied via an A-D converter (43), and the output of the encoder (41) is sent to an amplifier (44).
The signal is supplied to the digital recording head (21) via the digital recording head (21). Signal processing in the encoder (41) and AD converter (43) requires time τmad.

The output of the analog playback head (12) is supplied to a delay circuit (52) via an amplifier (51), delayed by τdem, and output to a cue signal output terminal (53). Also, the cue signal from the input terminal (61) is transmitted to the delay circuit (62).
) and delayed by τoIod time, and the amplifier (63
) to the analog recording head (22).

(101) is a time code signal generation circuit;
As shown in the figure, the output signal of the generation circuit (101) itself and the external time code signal are connected to the changeover switch (102).
) can be input selectively. When the switch (102) is in a connected state opposite to that shown, the generating circuit (101) is in free-running mode. Further, a PLL circuit (103) is connected to the generation circuit (101).

The output of the time code playback head (13) is sent to the amplifier (10).
4) is supplied to the time code detection circuit (105), and the reproduced time code signal detected by this circuit (105) is supplied to the delay circuit (106), delayed by τdeca time, and then sent to the time code signal generation circuit. (101). The time code signal from this generation circuit (101) is supplied to a delay circuit (107), delayed by τmod time, and supplied to a time code recording head (23) via an amplifier (10B).

In FIG. 2, (110) is a CPU (microcomputer) for tape running control, and (111) is a time code reader. A signal is provided. The output data of the reader (111) is stored in the RAM (112).
) and the data bus (113).
0). This CPU (110) also has the output data of the time code signal generation circuit (101) as RA.
M (114) and the data bus (113).

The operation of this embodiment is as follows.

The switch (102) in FIG. 2 is set to the illustrated connection state, and the time code signal generation circuit (101) enters the generate (slave lock) mode.

The time code recorded on the auxiliary track AUX2 of the tape T is reproduced by the head (work 3) and sent to the detection circuit (1
05), it is made into a TTL level reproduction time code signal. This reproduced time code signal is transmitted to a delay circuit (106
) and then supplied to the time code signal generation circuit (101).

As mentioned above, the delay time τdem of the delay circuit (106)
is equal to the signal processing time in the PCM decoder (31) and the DA converter (33), so the generation circuit (101)
The in-line nature of the reproduced time code signal at the input terminal and the analog signal at the output terminal (34) is maintained. Similarly, the in-line nature of both signals and the cue signal at the output terminal (53) is maintained.

In the time code signal generation circuit (101), time code signals with the same content are continuously generated (regenerated) in phase synchronization with the supplied reproduced time code signal, thereby eliminating discontinuity in the reproduced time code signal. etc. will be corrected.

This corrected time code signal is sent to the delay circuit (107)
The signal is delayed by 1106 hours and then supplied to the recording head (23).

As mentioned above, the delay time τ-od of the delay circuit (107)
is a PCM encoder (41) and an A-D converter (43)
Since it is equal to the signal processing time in the recording head (23
) and the recording head (21
) is maintained in-line with the PCM signal.

Similarly, the in-line nature of both signals and the cue signal in the recording head (22) is maintained.

After the time code of the auxiliary track AUX2 is reproduced by the reproduction head (13) until the corrected time code formed by the generation circuit (101) is re-recorded on the auxiliary track AUX2 by the recording head (23), ( rd
ew+τsod) time has passed. - On the other hand, the magnetic tape T runs the distance (du+dd) between the composite reproducing head (10) and the composite recording head (20) during this period. Therefore, the original time code recorded on the auxiliary track and the corrected time code re-recorded do not deviate from each other in the longitudinal direction of the track.

In the embodiment described above, the time code playback head (13
) and recording head (23) are arranged in-line with the digital signal playback head (1) and recording head (21), respectively, but the time code playback head (
13) and the recording head (23) are arranged on the reference line Lref, and the corresponding delay circuit (10
6) or (107) may be removed.

Furthermore, instead of the cue signal reproducing head (12) and recording head (22), a recording/reproducing head is disposed on the reference line L ref, and delay circuits (52) and (62) are provided.
may be removed.

〔Effect of the invention〕

As described in detail above, according to the present invention, a time code signal is formed based on the reproduced time code signal from the preceding playback head, and this time code signal is applied to the tape path between the preceding playback head and the recording head. Since the recording is delayed by a corresponding predetermined time, the original time code signal recorded discontinuously can be corrected to a continuous time code signal with the same phase and re-recorded in-line with the digital signal. A digital tape recorder that can perform the following functions is obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of an embodiment of a digital tape recorder according to the present invention, FIG. 2 is a block diagram showing the configuration of main parts of an embodiment of the invention, and FIG. FIG. 3 is a plan view for explanation. (10) is a composite playback head, (20) is a composite recording head, (31) is a PCM decoder, (41) is a PCM encoder, (52), (62), (106),
(107) is a delay circuit, (101) is a time code signal generation circuit, (112) is a time code signal detection circuit, T
is magnetic tape, AUX 1. AUX2 is an auxiliary truck,
DT is a digital recording track.

Claims (1)

[Claims] A digital tape recorder in which a digital signal and a time code signal are recorded on a magnetic tape via a recording head, comprising a preceding playback head and a time code signal reproduced from the preceding playback head. It is characterized by comprising a time code signal generation circuit that forms a time code signal to be supplied to the recording head, and a delay circuit that compensates for a time delay corresponding to a tape path between the preceding playback head and the recording head. A digital tape recorder.