KR0133512B1 - Teletext recording system for vtr - Google Patents

Abstract

The present invention relates to a system capable of directly recording a teletext signal of a character multiplex broadcast in a television, and conventionally records a teletext signal directly because the recording and playback bandwidth of the VLC is narrower than that of the teletext signal bandwidth. In this case, almost no recording or error occurred, so teletext decoding could not be performed on the playback screen. Accordingly, the present invention binarizes the teletext signal so that the teletext broadcast signal can be directly recorded, and converts the teletext signal into a quadrature analog signal so that the teletext signal can be recorded according to the vertical blanking signal. This is to enable recording of signals.

Description

VRT's Teletext Recording System

1 is a schematic diagram of a teletext recording system of VRC according to the present invention.

2 is a waveform diagram of parts of the teletext data of FIG.

3 (a) to (i) is a waveform diagram of each part according to FIG.

* Explanation of symbols for main parts of the drawings

1: Teletext double conversion switch 2: VLC recording unit

3: head 4: horizontal synchronous selector switch

5: teletext clock generator 8: divider

9: Teletext analog switch unit 10: Synchronous separation unit

11: vertical return time signal generator

The present invention relates to a teletext (TXT) signal recording system of V-Cal, and more particularly, to a teletext signal recording system of V-CAL for recording the teletext broadcasting directly to V-CAL to diversify the functions of V-CAL.

In general, in case of recording a broadcast signal in a VRT, it is difficult to record a teletext (TXT) signal, which is all text multicast signals. Since the recording and playback bandwidth of V-Cal is narrower than the bandwidth of 4.2MHz required for the text multicast signal, the recording of the teletext signal is almost impossible to record or the teletext decoding cannot be performed on the recording screen due to the error.

In view of the above problems, the present invention detects and binarizes a teletext signal (TXT) from an input composite video signal and records the tape of V-Cal as a quadrature analog signal, thereby reducing the bandwidth of the teletext signal. V-Tell's teletext signal recording system was created to enable recording, which will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a VRT teletext signal recording system according to the present invention. As shown in FIG. 1, a sync separator 10 for separating horizontal and vertical sync signals from a composite video signal (C-Video), and A vertical blanking time signal generator 11 for receiving a vertical blanking time signal (VBI) by receiving a horizontal sync (Hsyne) and a vertical sync (Vsync) signal of the sync separating unit 10; The teletext clock signal is inputted from the teletext data detector 5 for detecting the teletext data from the composite video signal C-Video, and the output of the teletext signal TXT from the teletext data detector 5. A teletext clock generator 7 for generating Tck, a divider 8 for dividing the teletext clock signal Tck into two, and the teletext clock signal Tck and a 1/2 divided teletext Binary the teletext signal TXT according to the clock signal 1 / 2Tck and then The selector switches 9-19, 9-2, 9-3, and 9- dividing the reference voltage (V) by dividing the reference voltage (V) by a constant ratio (1V, ⅔V, ⅓V, OV) according to the quantization data (Qd-Qa). 4) the output of the quantized analog signal switching unit 9 or the horizontal synchronous signal Hsync of the synchronous separation unit 10 for selecting and outputting the quantized analog teletext signal through the horizontal synchronous signal Hsync. The vertical retrace erase time (VB1) signal generating unit for converting the horizontal synchronous switching switch 4 and the digitized teletext signal output or the composite video signal C-Video of the horizontal synchronous switching switch 4 accordingly. 11) a teletext recording switch 1 for selective switching in accordance with the vertical blanking time VB1 signal and an output of the teletext recording switch 1 to the recording / playback head 3 for recording. It consisted of the V seed recording part 2.

FIG. 2 is a detailed view of the teletext signal converter of FIG. 1, and the half-divided teletext clock through the teletext clock (Tch) and the divider 98 outputted through the teletext clock generator 7 as shown in FIG. Flip-flop 6-1 receiving (½Tck) as clock signals CK1 and CK2, respectively, and receiving teletext data TXT of the textual data detection unit 5 common inputs D1 and D2. ), And outputs Q1 and Q2 of (6-2) to the inputs (A) and (B) of the 2to4 decoder (6-3) as binarized outputs, and the inputs (A) and (B). It is configured to make the qualitative inference force (Qa-Qd) according to).

The operation and effect of the present invention configured as described above will be described with reference to the timing diagram of each part of FIG. 3 according to the present invention.

The present invention is intended to change and record binary data into quantized data because the recording and playback bandwidth of V-Cal is narrower than the bandwidth of 4.2 MHz required for the character multicast signal.

The composite video signal (C-Video) is recorded by the recording head (3) through the VRC recording unit (2) when the vertical blanking time is not changed through the teletext recording switching switch (1) according to the vertical blanking time calculation signal (VBI). When the teletext data TXT, which is output to the recorded video and is recorded at the vertical blanking time of the composite video signal C-Video, is detected through the teletext data detector 5 as shown in FIG. 3A, a teletext clock is generated. The unit 7 generates a teletext clock Tck as shown in FIG. 3b, and the teletext clock Tck outputs ½ divided clock as shown in FIG. 3c through the divider 8.

Accordingly, the flip-flops 6-1 and 6-2 which receive the teletext data TXT [Fig. 3A], respectively, as inputs D1 and D2 are clock timings Tck in Figs. 3B and 3C. ) And (½Tck) to binarize the teletext data TXT at the same timing as 3d and 3e. According to the inputs (A) and (B) as shown in FIGS. 3D and 3E, the 2to4 decode (6-3) has a quantized output (Qa) when the inputs (A) and (B) are 00, 01, 10, and 11, respectively. ), (Qb), (Qc), and (Qd) have a high potential output as shown in Figs. 3f to 3i, and accordingly, each selector switch 9- of the quaternary analog signal switching unit 9 4), (9-3), (9-2), and (9-1) are switched respectively to selectively output 0V, ⅓V, 1V, and 1V. Through this quaternary analog signal switching unit (1) Is applied to the recording section 2 of the recording through the head (3).

At this time, the horizontal synchronization switch (4) selects the horizontal synchronization signal (Hsync) in the active period of the horizontal synchronization signal (Hsync), the teletext recording switch (1) is a tele only when the vertical blanking time signal (VBI) Select and record text signal.

That is, the composite video signal (C-Video) is a normal recording operation when the vertical blanking time is not, and the quadrupled teletext data is recorded during the vertical blanking time, and the teletext data is a horizontal synchronous signal ( Hsync) to record and sync to it.

As described above, the present invention has the effect of extending the function of V-CAL when the data is recorded by the teletext data of the character multi-broadcasting by quantizing the teletext data.

Claims (1)

A teletext data detector 5 for detecting the teletext data TXT from the composite video signal C-Video, a teletext generator 7 for detecting a synchronous clock of the teletext data detector 5, The frequency divider 8 that divides the teletext clock Tck, and the teletext data TXT are binarized according to the teletext clock Tck and the divided clock ½ Tck, and then quantized data (Qa-Qd) A tessellated analog signal outputted as an analog signal having different levels according to the teletext signal converting section 6 to be output and the quantized data Qa-Qd of the teletext signal converting section 6 Vertical blanking to generate a vertical blanking time signal VBI in accordance with the switching unit 9 and the sync signals Hsync and Vsync separated from the composite video signal C-Video through the sync separating unit 10. The horizontal synchronization signal according to the time signal generator 11 and the horizontal synchronization signal Hsync of the synchronization separator 10. (Hsync) and the horizontal synchronous switching switch (4) for selectively switching the output of the quantized analog signal switching unit 9, the output of the horizontal synchronous switching switch (4) and the composite video signal (C-Video) And a teletext recording switch (1) for switching in accordance with the vertical blanking time signal (VBI) and outputting the same to the BC recording unit (2).