JP2923963B2 - Bit rotation system in digital video recorder - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording technique for video equipment handled by a broadcasting station, post-production, and the like, and more particularly, to a recording method that converts a video signal into PCM and records one or more fields in the form of digital data. The present invention relates to a bit rotation system for exchanging data bits in an apparatus, a so-called digital recording and reproducing apparatus.

[Prior Art] Conventionally, a recording apparatus such as a VTR performs restoration of a recording medium with a complicated circuit such as error code correction.
In general, in a digital television special effect device, an erroneous bit is generally replaced with the least significant bit, that is, an LSB, for emergency use.

[Problems to be solved by the invention]

However, in the former case, there is a problem that the circuit scale becomes large and the cost increases. The latter is optimal for emergency use in terms of circuit size and cost,
When bit errors of different weights occur in a plurality of fields, that is, in a recording apparatus for recording a plurality of fields, for example, the first field is MSB, and the second field is 2nd field.
There is a problem that if a bit breaks down, it cannot be saved.

[Means for solving the problem]

In order to solve such a problem, the present invention is provided at a stage preceding a recording medium in a digital recording apparatus for recording a video signal in the form of digital data of a predetermined number of bits on a recording medium for one or more fields. A first bit rotation circuit for exchanging bits for digital data of a predetermined number of bits, and
A second bit rotation circuit for exchanging bits for a predetermined number of bits of digital data, and a memory for storing bit rotation information for bit rotation for exchanging defective bits and lower bits of a recording medium for each field A first bit rotation circuit that replaces the defective bit and the lower bit of the video signal according to the bit rotation information, and a second bit rotation circuit that outputs the video signal recorded on the recording medium. The replacement of the defective bit with the lower bit of the signal is performed according to the bit rotation information.

[Action]

In the present invention, by performing bit rotation (bit replacement) for each field, bit rotation can be performed in a plurality of fields.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram for explaining one embodiment of a bit rotation system in a digital recording apparatus according to the present invention.

In this embodiment, a digital recording device that records a PCM-converted video signal 11 on an image recording medium 2 as a recording medium in a field or more is used in a bit rotation in which bit weights are exchanged between the front and rear stages of the image recording medium 2. Circuit 1,
3, a storage unit 4 for storing bit rotation information such as a field number corresponding to each field of the image recording medium 2 and bit rotation control data, and a control unit 5 for controlling them. Thus, bit rotation is performed for each field unit. Here, the bit rotation circuits 1 and 3 switch the bus so that the PCM video signal 11 treats the defective bit of the image recording medium 2 as the least significant bit (LSB). Control data 1
It is switched by 2,13. The image recording medium 2 has a recording capacity for a plurality of fields, and data 14 of the field number is sent to the control unit 5.

Thus, according to the recording device configured as described above,
One bit rotation circuit 1 converts a defective bit (MSB) to a least significant bit (LSB) as shown in FIG.
B), and the other bit rotation circuit 3 has a function of returning the original weight to the original weight after replacing the least significant bit and the defective bit at the subsequent stage of the image recording medium 2 as in the preceding stage. At this time, there are eight types of exchange patterns. Therefore, when a high-order bit of the image recording medium 2 becomes defective, it can be made inconspicuous by treating the bit as an LSB.
If the bit position of the error is different for each field, the error can always be brought to the least significant bit by exchanging the bit each time.

〔The invention's effect〕

As described above, according to the present invention, a digital recording apparatus is provided with a bit rotation circuit for changing the bit weights at the front and rear stages of a recording medium, and performs bit rotation for each field, thereby recording a plurality of fields. When a high-order bit of the medium becomes defective, the bit can be handled as an LSB, so that the bit can be made inconspicuous. In addition, when the bit position of the error is different for each field, the error is always brought to the least significant bit by exchanging the bit each time, so that the error can be made inconspicuous.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining an embodiment of the present invention. 1,3 ... Bit rotation circuit, 2 ... Image recording medium, 4 ... Storage unit, 5 ... Control unit.

Claims (1)

(57) [Claims] 1. A digital recording apparatus for recording a video signal in the form of digital data having a predetermined number of bits on a recording medium for at least one field, wherein the digital data having the predetermined number of bits is provided at a stage preceding the recording medium. A first bit rotation circuit for exchanging bits with respect to a second bit rotation circuit provided at a subsequent stage of the recording medium and exchanging bits for the digital data having the predetermined number of bits; A storage unit that stores bit rotation information for bit rotation for replacing a defective bit and a lower bit of the recording medium for each field; and wherein the first bit rotation circuit is configured to store the bit rotation information of the video signal. Replacing the defective bit with the lower bit in accordance with the bit rotation information; The bit Rotation in method in digital recording apparatus and performing the defective bit and the lower bit substitution of recorded video signal to said recording medium in accordance with the bit Rotation in information.