JPH05128746A - Time code reader - Google Patents

Abstract

PURPOSE:To provide a time code reader which can correctly read a time code even when an error signal due to noise, etc., is included in a coded signal coded in a time base direction. CONSTITUTION:A cycle measuring circuit 12 measures the time during the pulse change of a time code signal S1 inputted to an input terminal 11 and outputs it to a cycle data correcting part 21 as measuring time data D1. The cycle data correcting part 21 removes error data De from the measuring time data D1 based on a signal S2 of a constant cycle T from a constant cycle T arithmetic part 22 and outputs them to a time code decoding part 23 as correcting time data D2. The time code decoding part 23 decides the '0' or '1' of the time code from the correcting time data D2 based on the signal S2 of the constant time T from the constant cycle T arithmetic part 22 and outputs the decoded result D3 to an output terminal 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a time code reading device for reading a time code recorded as time information or position information on a video tape, a digital audio tape or the like.

[0002]

2. Description of the Related Art As a method for digitally recording a time code, for example, a time code defined by SMPTE, on a video tape, there is, for example, a bi-phase mark system. As shown in FIG. 4, this is a method of encoding 0 or 1 depending on whether or not there is a pulse transition at an intermediate position of a constant cycle T.

The structure of a conventional time code reading device 1 is shown in FIG. The input terminal 2 receives a binarized signal of the reproduction signal of the time code recorded on the video tape. As shown in FIG. 4, the cycle measuring circuit 3 includes an input terminal 2
The time (cycle) t _{1 to} t ₇ between the pulse transitions of the binarized signal from is measured. The arithmetic circuit 4 decodes the time code based on the measurement result of the cycle measuring circuit 3, and outputs the output terminal 5
Output to.

[0004]

However, in the above-mentioned conventional example, when the output of the reproduction signal of the time code recorded on the tape is lowered or the reproduction signal contains noise, the case of binarization is shown. 1 of constant period T in 4
There is a case that pulse transition occurs at a period much smaller than / 2, and the time code is erroneously decoded.

Therefore, the present invention eliminates the above-mentioned drawbacks, and correctly reads the time code even if the coded signal obtained by coding the time code in the time axis direction includes an error signal due to noise or the like. An object of the present invention is to provide a time code reading device capable of performing.

[0006]

In order to achieve the above object, the present invention provides a time code reading apparatus for decoding a time code encoded in the time axis direction, in which a signal encoded in the time axis direction is time-coded. Conversion means for converting to an information signal; removal means for determining whether or not the time information signal contains an error signal, and removing the error signal when it is determined to contain it, and this removal means And a decoding means for decoding the time code based on the time information signal from which the error signal has been removed.

[0007]

The operation of the apparatus having the above construction will be described.

The converting means converts the input code signal of the time code into a time information signal and outputs it to the removing means.
The converted time information signal may include an error signal due to the influence of noise or the like. The removing means determines the presence or absence of an error signal, and when determining that the error signal is included, removes the error signal from the time information signal,
Output to the decoding means. The decoding means correctly decodes the time code based on the time information signal from which the error signal has been removed.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a time code reading apparatus 10 according to an embodiment of the present invention. The present apparatus 10 includes a cycle measuring circuit 12 as a converting means for measuring a time (cycle) between pulse transitions of a time code signal S ₁ as an encoded signal input to an input terminal 11, and a measurement by the cycle measuring circuit 12. An arithmetic processing unit 20 which decodes the time code based on the result and outputs the decoded result D ₃ to the output terminal 13 is roughly configured.

For example, as shown in FIG. 2, the cycle measuring circuit 12 measures the time of the "1" level portion and the time of the "0" level portion of the time code signal S ₁ , respectively,
Calculation processing unit 2 as measurement time data D ₁ (t _{1 to} t 12)
It outputs to 0.

The arithmetic processing unit 20 includes a cycle measuring circuit 12
Measured time data D ₁ to error data D
Period data correction unit 21 as a removing unit that removes and corrects e, and constant period T calculation unit 22 that calculates constant period T
And a time code decoding unit 23 that decodes a time code based on the measured time data D ₁ or the corrected time data D ₂ sent.

FIG. 2 is a waveform diagram showing a case where the reproduced signal of the time code contains noise or noise is mixed in the time code signal S ₁ .

The periodic data correction unit 21 has a fixed period T
As shown in FIG. 2, the correction time data D is obtained by removing the error data De from the measurement time data D ₁ input from the cycle measuring circuit 12 based on the signal S ₂ of the constant cycle T input from the calculation unit 22. ₂ (t ′ _{1 to} t ′ ₆ ) is output to the constant period T calculation unit 22 and the time code decoding unit 23. That is, the cycle data correction unit 21 removes the error data De that is much smaller than 1/2 of the constant cycle T, for example, smaller than T / 10, and removes the error data De. In FIG. 2, the measurement time data (t ₃ , t ₆ , t 11) is the data corresponding to the error pulse Pe. In the method of removing the error data De, assuming that the measurement time of the error pulse Pe is tne, the data tn− ₁ , tne, and tn + ₁ including the data before and after the error pulse Pe are converted into the error pulse Pe.
If there is no data, one data of level "0" or "1" is replaced by t '= tn- ₁ + tne + tn + ₁ . In this case, even if there are two or more error pulses Pe within the constant period T, it is possible to similarly correct.

The constant period T calculation unit 22 uses the measurement time data D ₁ from the period measurement circuit 12 at the time of starting, and uses the correction time data D ₂ from the period data correcting unit 21 after being stabilized after the start. To obtain the correct cycle T.

The time code decoding unit 23, based on the signal S ₂ of the constant period T from the constant period T calculation unit 22, the correction time data D ₂ (t ′ _{1 to} t ′ ₆₎ from the period data correction unit 21. ), The time code “0” or “1” is determined, and the decoding result D ₃ is output to the output terminal 13.

Next, the time code reading apparatus 1 of the above embodiment
The action of 0 will be described.

The time code signal S1 encoded by the biphase mark method is input to the input terminal 11. The cycle measuring circuit 12 measures the time between pulse transitions of the time code signal S ₁ input to the input terminal 11 and outputs it as the measurement time data D ₁ to the cycle data correcting section 21 and the constant cycle T computing section 22. .. Periodic data correction unit 21
Is a fixed cycle as correction time data D ₂ by removing the error data De from the measurement time data D ₁ from the cycle measuring circuit 12 based on the signal S ₂ of the fixed cycle T input from the fixed cycle T calculation unit 22. It is output to the T calculation unit 22 and the time code decoding unit 23. The constant period T computing unit 22 uses the measurement time data D ₁ from the period measuring circuit 12 at the time of starting, and uses the correction time data D ₂ from the period data correcting unit 21 after stabilizing after the start to obtain the correct period T. And the cycle T
The signal S ₂ is output to the period data correction unit 21 and the time code decoding unit 23. The time code decoding unit 23, based on the signal S ₂ of the constant period T from the constant period T calculation unit 22,
The time code “0” or “1” is determined from the correction time data D ₂ from the cycle data correction unit 21, and the decoding result D ₃ is output to the output terminal 13.

According to the time code reading apparatus 10 of the above-described embodiment, the error code Pe of the wrong time code due to the influence of noise or the like on the time code signal S _1.
Even if it is included, it can be removed and corrected, so that the correct decoding of the time code is possible.

The present invention is not limited to the above embodiment,
Various modifications can be made without departing from the spirit of the invention.

[0021]

As described above, according to the present invention, even if an error signal due to noise or the like is included in an encoded signal encoded in the time axis direction, the error signal is removed by the removing means. Therefore, it is possible to provide a time code reading device that can correctly read the time code.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a time code reading device according to an embodiment of the present invention.

FIG. 2 is a waveform chart showing the operation of the device shown in FIG.

FIG. 3 is a schematic configuration diagram of a conventional time code reading device.

FIG. 4 is a waveform chart showing the operation of the device shown in FIG.

[Explanation of symbols]

 10 time code reading device 12 cycle measuring circuit (converting means) 21 cycle data correcting section (removing means) 22 constant cycle T computing section 23 time code decoding section D1 measurement time data D2 correction time data S1 time code signal S2 constant cycle T signal

Claims (1)

[Claims] 1. A time code reading device for decoding a time code encoded in the time axis direction, wherein a conversion means for converting a signal encoded in the time axis direction into a time information signal, and an error in the time information signal. It is determined whether or not a signal is included, and when it is determined that the signal is included, removal means for removing the error signal, and the time code based on the time information signal from which the error signal is removed by the removal means And a decoding means for decoding the time code reading device.