JPS63244446A - Reproducing device - Google Patents

Abstract

PURPOSE:To process a reproducing through the use of a conventional reproducing signal processing circuit even when a signal recorded in a signal block of a recording medium is reproduced in the opposite order to the order of signal recording by providing a means rearranging the reproducing signal in a prescribed order. CONSTITUTION:When the signal recorded in the signal block of a recording medium 1 is reproduced by rotary heads A, B in the order opposite to the signal recording order, a signal separation means separates and extracts the signal for error detection from the reproducing signal. Then the detection means uses the error detection signal to detect the error for each signal block and outputs a detection signal when no error exists. On the other hand, the reproducing signal is rearranged by a means rearranging the reproducing signal in the opposite order to the reproduced order by the rotary heads A, B, that is, the same order as that recorded on the signal block. Thus, even when the rotary head is driven reversely from the recording, the reproducing signal is rearranged in the same order as the order of the signals recorded on the signal block and fed to the succeeding signal processing circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a playback device suitable for use in a digital audio tape recorder using a rotary head, and more particularly to a signal processing means of the playback device.

[Summary of the invention]

The present invention provides a reproducing apparatus for reproducing a recording medium using a rotary head, which is provided with means for rearranging reproduced signals in a predetermined order. Even when the reproduction signal is reproduced in the reverse order, the reproduction signal can be processed using a conventional reproduction signal processing circuit.

[Conventional technology]

As a rotary head type recording/reproducing device, for example, R-DAT
A rotary head type digital audio tape recorder called a digital audio tape recorder has been developed.

Next, the tape format and data format of the tape recorder based on the R-DAT system will be explained with reference to the drawings.

FIG. 3 shows the tape format. The magnetic tape 1 has a track 2A recorded by a first rotating magnetic head (hereinafter simply referred to as head A) and a second rotating magnetic head (hereinafter simply referred to as head B). The trunks 2B recorded by the tape 1 are formed diagonally and alternately with respect to the longitudinal direction of the tape 1. Note that the heads A and B, which have different azimuth angles from each other, are provided on a rotating drum with an interval of approximately 180 degrees. Then, while A and B are rotated once by the rotating drum, track 2A is rotated approximately 1/2 rotation each.
, 2B are formed. Furthermore, the rotary drum A1B scans the tracks 2A and 2B in the direction of arrow f by rotating the rotary drum in a predetermined direction.

One track 2A (2B) is called one segment and is divided into 196 data blocks. Of these, 34 blocks at both ends serve as auxiliary data areas, and 128 blocks at the center serve as a PCM area. The auxiliary data area is further divided into several sections, and in the corner sections, predetermined signals such as subcodes, PLL run-in signals, and AFT signals serving as pilot signals for tracking servo are recorded. , there is also a no-signal section.

Further, in the PCM fJ area, a signal obtained by converting an audio signal into PCM is recorded together with other predetermined data. This PCMw4 area consists of 128 data blocks,
One block is constructed as shown in FIG.

In FIG. 4, one block consists of 288 bits, and an 8-pin (1 symbol) block synchronization signal is added to the beginning of the block, followed by an 8-bit PCM-ID. A block address is added next to this PCM-ID. Simple parity error detection encoding processing is performed on the two symbols (W+ and WZ) of the PCM-ID and block address, and 8-bit parity (P) is added next to the block address. As shown in Figure 5, the block address is
It is made up of 7 bits excluding the MSB, and the most significant bit is set to "0" to indicate that it is a PCM block. This 7-bit block is (
00) ~ (7F) (hexadecimal display), that is, "0" ~ r1
It changes sequentially to 27J. Also, the lower 3 of the block address
Bits are (000) (010) (100)
PCM- recorded in each EVEN block of (110)
An ID is determined. Also, the lower 3 of the block address
The bit is (OO1) (011) (101) (11
Each ODD block address in 1) can record an optional code of PCM-ID.

The above PCM-ID contains 2-bit ID1 to rD.
8 and a 4-bit frame address. ID1
Identification information is defined for each of ~rD8. This identification information includes, for example, identification of audio use or other use, program start, pre-emphasis on/off, pre-emphasis characteristics, sampling frequency, etc.

The above frame address is composed of 4 pins. The same frame address is given to tracks 2A and 2B. That is, the tracks 2A and 2B formed by one rotation of the spatula FAXH have the same frame address. This frame address is sequentially and repeatedly recorded as rOJ to rFJ in the PCM-ID section (W,) of the EVEN block address.

In a digital audio tape recorder having the tape format and data format described above, during playback, the rotating drum is usually rotated in the same direction as during recording, and the heads A and B are rotated as shown in FIGS. 3 and 4. Reproduction is performed by scanning in the direction of arrow f. There are various types of rotating drums, such as an upper drum rotating type, a middle drum rotating type, and a lower drum rotating type. Further, when the heads A and B scan the tape 1, an air film layer is formed between the tape 1 and the head A1B in order to reduce friction between the two.

[Problem that the invention seeks to solve]

When downsizing the above-mentioned digital audio tape recorder, it has been found through experiments that the direction of rotation of the drum that can form an air film layer between it and the tape 1 differs depending on the type of the above-mentioned rotating drum. . That is, depending on the above-mentioned upper drum rotation type, middle drum rotation type, and lower drum rotation type, the preferable rotation direction of the drum for forming the air film layer may be different from each other.

Therefore, when a tape recorded using one type of rotating drum is played back using a different type of rotating drum, various signals recorded sequentially in the direction of the arrow f in FIGS. 3 and 4 during recording are During reproduction, heads A and B must scan in the direction of arrow g, and reproduction must be performed from the opposite direction to that during recording.

In order to process the reproduced data obtained in this manner with a conventional data processing circuit, it is necessary to rearrange the reproduced data in the order of the signals at the time of recording.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a reproducing apparatus that can rearrange reproduced data when rotating a rotating drum in a direction opposite to that during recording during reproduction.

[Means for solving problems]

The present invention provides a reproducing apparatus that uses a rotary head to reproduce a recording medium in which a recording track is provided with a plurality of signal blocks, and an error detection method based on a reproduced signal of the signal block obtained from the rotary head. a signal separating means for separating and extracting the signals; and a detecting means for detecting an error for each signal block using the error detection signal obtained from the signal separating means and outputting a detection signal when there is no error; means for rearranging the reproduction signals in an order opposite to the order in which they were reproduced by the rotary head, and outputting the rearranged signals when the detection signal is output from the detection means. be.

[Effect]

According to the present invention, when the signals recorded in the signal block of the recording medium are reproduced by the rotary head in the reverse order to the order in which they were recorded, the signal separating means first converts the reproduced signal into an error detection signal. Separate and extract. Then, the detection means uses this error detection signal to perform error detection for each signal block, and outputs a detection signal if there is no error. On the other hand, the reproduced signals are rearranged by means for rearranging the reproduced signals into an order opposite to the order in which they were reproduced by the rotary head, that is, the same order as the order recorded in the signal block. The rearranged signals are outputted and supplied to the subsequent signal processing circuit when the detection signal is outputted from the detection means.

〔Example〕

An embodiment in which the present invention is applied to a rotary head type digital audio tape recorder will be described below with reference to the drawings.

In FIG. 2, the tape 1 fed out from the supply reel 2 is wound around the circumferential surface of the drum 3 at an angle of about 90 degrees, and then is run in the direction of arrow a by the capstan 4 and pinch roller 5, and then attached to the take-up reel 6. It is wound up. The rotating drum 3 is provided with heads A and B having different azimuth angles at an interval of approximately 1806 mm. The heads A and B are configured to be rotated by a rotating drum 3 in the direction of arrow C or the direction of arrow d.

During playback, playback signals alternately obtained from heads A and B are sent to contact a of switch 9 through playback amplifier 7.8.
, b. The switch 9 can switch between contacts a and b by a switching pulse obtained from a timing signal generation circuit 60, which will be described later.

The reproduced signal is then supplied to the subsequent reproduced signal processing circuit through the equalizer 11, limiter 12, data rearrangement circuit 30, and demodulation circuit 13.

The data rearrangement circuit 30 is configured as shown in FIG.
When reproduced data is supplied from the register 2, this reproduced data is first taken into the register 31 in 10 bits. Here, it is assumed that the changeover switch 32 for selectively switching the rotation direction of the rotary heads A and B between forward and reverse is switched to the contact 32a side, and the rotary heads A and B are rotated in the forward direction. That is, it is assumed that it is rotated in the same direction as during recording (for example, in the direction of arrow C in FIG. 2).

When the switch 32 is switched to the contact a side, [HJ
(high level) signal is applied to multiplexer 34.36. As a result, multiplexers 34 and 36 detect predetermined data at a predetermined timing from data read from register 31 and registers 40 and 41, which will be described later.

Further, the synchronization signal detection circuit 33 detects a synchronization signal from the data read from the register 31, and operates the timing signal generation circuit 60 based on this detection. As a result, the timing signal generation circuit 60 generates a predetermined timing signal and applies it to the register 35, multiplexer 38, and the like. Further, the data read from the register 31 is taken into a register 40 having a capacity for one block.

The multiplexer 34 selects data related to error detection codes such as W, . The multiplexer 36 also outputs the PC from the register 40.
M data is selected and supplied to the register 37. First, the data regarding W1, W2, and parity in the register 35 are selected by the multiplexer 38 and applied to the demodulation circuit 13.

Note that the multiplexer 38 is controlled by the timing signal generation circuit 60 so as to preferentially pass the data held in the register 35 among the data held in the registers 35 and 37.

The parity check circuit 39 calculates P=WI + based on the data regarding Wl, W2, and P obtained by the demodulation circuit 13.
A CRC (parity) check is performed to satisfy W2, and when the check result is correct, a signal OK is applied to the timing signal generation circuit 61 and the control circuit 50.

l The timing signal generation circuit 61 sends a timing signal to the register 37 when the signal OK is applied,
As a result, register 37 becomes the PC that was held until then.
The M data is supplied to the demodulation circuit 13 via the multiplexer 38.

The data supplied to the demodulation circuit 13 is demodulated from 10 bits per symbol to 8 bits per symbol. During recording, the 8 bits of one symbol are subjected to digital modulation processing that converts them into a preferred 10-bit pattern in order to reduce the low-frequency components as much as possible, so this is restored to the original form of 8 bits of one symbol. -It is necessary to do so.

This demodulated signal is then supplied to the reproduced signal processing circuit at the subsequent stage.

Next, the operation when the rotary heads A and B are rotated in the opposite direction to the rotation direction during recording will be described.

Direction of rotation of rotating heads A and B during recording (arrow C in Figure 2)
When the selector switch 32 is switched to the contact 32b side in order to rotate the switch 32 in the direction opposite to the direction (direction), that is, in the direction of the arrow d in FIG.
Added to 36. And from limiter 12 to register 3
The PCM data that has been reproduced and taken in in the opposite direction to that when it was recorded is taken into the register 40. Further, the synchronization signal detected by the synchronization signal detection circuit 33 is applied to the timing signal generation circuit 60 in the same manner as in the case of forward rotation of the head AB described above.

The register 40 separates the data related to w, , w, , p for error detection from the supplied data and adds it to the register 41, and also stores the remaining PCM data from which the data related to W, , W, , P has been separated. RAM42.43
selectively supplied to

Data related to Wl, wz, and P are taken into the register 41 in the reverse order from when they were recorded. That is, rotating head A
, B are the trunks 2A, 2B and P shown in FIGS. 3 and 4.
Data is captured in the opposite direction to scan the CM block in the direction of arrow g. Then, the register 41 rearranges the data taken in in this order into the normal order according to a control signal from the control circuit 51 and sends the data to the multiplexer 34.
is added to register 35 via. Note that the control circuit 51 outputs the control signal when a synchronization signal is applied from the synchronization signal detection circuit 33. On the other hand, RAM42.
43 are controlled by a control circuit 50 so that when one is in a write state, the other is in a read state. Note that the control circuit 50 includes the parity check circuit 3
RAM42.43 only when signal OK is added from 9.
Add a control signal to

Now, when a signal OK is output from the parity check circuit 39 and a control signal from the control circuit 50 is applied to the RAMs 42 and 43, for example, the RAM 42 enters the write state and the reproduced data supplied from the register 40 is uploaded for the RAM address. /Memorize based on the address up signal supplied from the down counter 44. On the other hand, the RAM 43 which has been in the write state until now is stored in the control circuit 5.
It is switched to the read state by a control signal from 0,
The written data is supplied to the register 46 through the multiplexer 45. At this time, the counter 44 applies an address down signal to the RAM 43 in response to a control signal from the control circuit 50. With this signal, during recording, the RAM is
The data written in RAM 43 is read out from RAM 43 in the reverse order of the address order in which it was written.

As a result, heads A and B are rotated in the opposite direction to the direction in which they were recorded, so that the data is reproduced in the reverse order to that in which it was recorded, and the data taken into the RAM 42, 43 in this state is recorded on the tape 1. rearranged in the same order as the original signals.

The data taken into the register 46 in this way is supplied to the multiplexer 36, and is sent to the multiplexer 38 and demodulator 38 in the same manner as when the nodes A and B are rotated in the direction of arrow C in FIG. The signal is supplied to the subsequent reproduction signal processing circuit via the circuit 13.

As described above, according to this embodiment, even if the rotary heads A and B are rotated in the forward or reverse direction to reproduce the tape 1, the same reproduction signal processing circuit can process the reproduction signal. can.

〔Effect of the invention〕

According to the present invention, even if, for example, the rotary head is rotated in the opposite direction to that during recording and the signals recorded in the signal blocks of the recording medium are reproduced in the reverse order to the order in which they were recorded, this The reproduced signals are rearranged in the same order as the signals recorded in the signal block and supplied to the subsequent signal processing circuit, so the rotary head is rotated in the same direction as when recording and the reproduced signals are rearranged in the same order as the signals recorded in the signal block. It becomes possible to process the reproduced signal using a conventional signal processing circuit.

Moreover, since the reproduction signal supplied to the subsequent signal processing circuit is only the error-free reproduction signal that has been subjected to an error check by the detection means, it is possible to accurately reproduce the data recorded in the signal block.

Therefore, according to the present invention, the direction of rotation of any type of rotating drum can be selected in the direction in which the error film is formed, so that it is possible to select various types of rotating drums in order to downsize the device. becomes.

[Brief explanation of the drawing]

1 and 2 are block diagrams showing one embodiment of the present invention, FIG. 3 is a diagram showing a tape format, and FIG. 4 is a block diagram showing an embodiment of the present invention.
FIG. 5 is a diagram showing the format of w, , w, , p in the PCM data block format of FIG. 4. In addition, in the symbols used in the drawings, 1----------1----Magnetic tape 3------m------Rotating drum 39
−−−−−−−−−−−−−−−Parity check circuit 40 −−−−−−−−−−−−−−−Register 42,
43---------------------RA M44--
----------- RAM address up/down counter 50---------------- Control circuits A, B, --- ---------Rotating heads 2A, 2B--------One track.

Claims (1)

[Scope of Claims] In a reproducing apparatus that uses a rotary head to reproduce a recording medium in which a plurality of signal blocks are provided on a recording track, an error is detected from a reproduced signal of the signal block obtained from the rotary head. a signal separation means for separating and extracting a detection signal; and a detection means for detecting an error for each signal block using the error detection signal obtained from the signal separation means and outputting a detection signal when there is no error. and means for rearranging the reproduced signals in an order opposite to the order in which they were reproduced by the rotary head, and outputting the rearranged signals when the detection signal is output from the detection means. A playback device characterized by: