JP2585317B2 - Time information transmission method and its receiving device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for transmitting time information using a vertical blanking period of a television signal and a receiving device therefor.

(Summary of the Invention) The present invention relates to a method for transmitting time information using a vertical blanking period of a television signal and a receiver thereof, wherein a transmitting side uses a horizontal synchronizing signal of a television signal and a color subcarrier signal. A time information data packet is obtained from the obtained clock signal and multiplexed in the vertical flyback period for transmission. At the receiving side, the transmitted time information data packet is extracted. Play time information synchronized with time information.

As a result, time information synchronized with each other can be obtained at both the transmitting and receiving terminals.

(Prior Art) Conventionally, transmission of time information has been carried out in the broadcasting field by a method using an announcement / comment or a method of superimposing a video. Similarly, in other fields, means for reporting the time by acoustic means has been common.

On the other hand, in the case of multiplexing various signals during the vertical blanking period of video, teletext broadcasting has been put into practical use and various service broadcasts have been made. However, transmission of precise time information was carried out due to data transmission capacity. There was no example.

(Problems to be Solved by the Invention) Simply transmitting the time information by video or audio means lacks developability. For example, if there is a time difference in the service area, it is necessary to take new means. In this sense, the advantage of the method of transmitting the encoded time information is obvious.

If time information is simply multiplexed during the vertical blanking period of an image, the NTSC signal standard requires a field frequency of 60 ×
1000/1001, which is inconsistent with 1 second, which is a unit of normal time, and causes a time error on the order of 10 ^-3 .

Therefore, the object of the present invention is to provide a 1 ms
Time information transmission that enables unit-encoded time information to be obtained in a synchronized state at both ends of transmission and reception, and that not only provides a time signal service but also has expandability so that it can be used for various services. It is intended to provide a method and its receiving device.

In addition, in order to further reduce the load on the transmission path, despite the fact that time information in units of 1 ms is obtained, the capacity required for information transmission is most easily reduced to the order of several hundred bits / second. The receiving device is not provided.

(Means for Solving the Problems) In order to achieve this object, the time information transmission method of the present invention transmits the time information using the vertical blanking period of the television signal. A time information generating circuit is driven by a first clock signal obtained from the horizontal synchronizing signal to generate time information data, and the time information data is converted to a second clock signal obtained from a color subcarrier of a television signal. And converts the converted time information data packet into a vertical flyback period and transmits the multiplexed time information data packet. On the receiving side, the second information obtained from the color subcarrier of the television signal is obtained. Extracting the time information data packet transmitted by the clock signal and the extraction gate signal obtained from the vertical synchronization signal and the horizontal synchronization signal, The reproduction time information data generated from the time information reproduction circuit driven by the first clock signal obtained from the horizontal synchronization signal of the John signal is used as the time information data extracted from the extracted time information data packet. By calibrating,
The time information synchronized with the time information on the transmitting side is reproduced.

Further, the time information receiving apparatus of the present invention generates time information data by driving a time information generating circuit with a first clock signal obtained from a horizontal synchronizing signal of a television signal. Receiver for converting a time information data packet with a second clock signal obtained from a color subcarrier and multiplexing the converted time information data packet during a vertical flyback period and receiving a transmitted signal Means for extracting a time information data packet transmitted by said second clock signal obtained from a color subcarrier of a television signal and an extraction gate signal obtained from a vertical synchronizing signal and a horizontal synchronizing signal. Means for extracting time information data from said time information data packet; and said means obtained from a horizontal synchronization signal of a television signal. A means for generating reproduction time information data driven by one clock signal; and a means for calibrating the reproduction time information data with the time information data, and reproducing the time information synchronized with the time information on the transmission side. It is characterized by the following.

(Example) Hereinafter, the present invention will be described in detail by way of examples with reference to the accompanying drawings.

FIG. 1 is a schematic block diagram showing an embodiment of a transmitting and receiving apparatus required for carrying out the method of the present invention.

In FIG. 1, a transmitting unit 1 includes a synchronous reproduction circuit 2, a video inserter 3, phase locked loop circuits (hereinafter, PLLs) 4, 5,
A time information generating circuit 6, a time information data packet generating circuit 7, and a roll-off filter 8;
Reference numeral 11 denotes a synchronous reproducing circuit 12, a data killer 13, phase locked loop circuits 14 and 16, a line counter 15, a digital data reproducing circuit 17, a time information data / packet extracting circuit 18, and a time information reproducing circuit 19.

The transmitting unit 1 calculates 1k from the horizontal synchronizing signal of the television signal.
Hz is reproduced to generate time information, which is 5.73 MHz obtained from the color subcarrier signal (8 / 5f _sc , f _sc is the color subcarrier frequency)
The clock is converted into a data packet by the above clock and further multiplexed in the vertical blanking period of the video signal. Meanwhile digitally reproduce the video at the receiving unit 11 5.73MHz reproduced synchronously as with transmitting unit in (8 / 5f _sc), the line of the multiplexed vertical blanking period of these time information data packets at gate extraction Based on the extracted information of the time information data packet, the time reproduced at 1 kHz synchronously reproduced in the same manner as the transmission unit is calibrated, and time information synchronized by both the transmission and reception units is obtained.

 Hereinafter, each part will be described in more detail.

Obtaining a horizontal synchronizing signal f _h and the chrominance subcarrier signal f _sc from first video signal input to the synchronous reproduction circuit 2 the transmitter 1. These are input to PLL4 and PLL5, respectively. In PLL4 For NTSC signal f _h × 1001 / by (30 × 525), also PLL5 the f
1kHz and 5.73MHz signals are obtained by _sc × 8/5. The signal 1 kHz is input to the time information generating circuit 6 to operate the counter and generate time information data in units of 1 ms.
This situation is shown in FIG. 2 (a), as an example.
For example, the hour, minute, second, and millisecond binary data
The time information generation circuit 6 changes and outputs the clock every 1 kHz. This data output is a parallel output.

This time information is stored in the time information data packet generation circuit 7.
And is generated as a data packet with a clock rate of 5.73 MHz obtained by PLL5. Generated data
An example of a packet format is shown in FIG. 2 (b), which corresponds to the length of one line of a television signal. Then, the generation circuit 7 performs a so-called series-para conversion. Now the data generated in this way
The packet signal is band-limited by the roll-off filter 8 to the 6 MHz band of NTSC, and is multiplex-transmitted to the line specified in the vertical retrace period.

Next, in the receiving unit 11, the multiplexed video signal is input to a synchronous reproduction circuit 12 and a data killer 13, and from each of them, a horizontal synchronizing signal f _h , a vertical synchronizing signal f _v , a color sub-carrier signal f _sc and a video signal A video signal from which a data packet portion has been removed is obtained. Of these, the color subcarrier signal _fsc is PLL1
4, vertical sync signal _fv is line counter 15, horizontal sync signal f
_h is input to the PLL 16 and the line counter 15, the PLL 14 outputs 5.73 MHz similarly to the transmitting unit, the line counter 15 receives a gate signal indicating a line in the multiplexed vertical retrace period of the time information data packet, and 1 kHz is obtained from the PLL 16 as in the transmission unit.

The frequency of 5.73 MHz is input to the digital data reproducing circuit 17 and binarizes the video portion of the multiplexed video.
The binary digitized video signal contains time information data
The line on which the time information is multiplexed is extracted by the packet extraction circuit 18, and only the time information is extracted and input to the time information reproduction circuit 19 to be used for the calibration of the reproduction time. One example of this situation is shown in FIG. 2 (c).

With the above procedure, time information synchronized with each other can be obtained at both the transmitting and receiving units.

Since both transmitting and receiving terminals have their own time counters,
The transmission of the time information may be performed in a relatively long cycle,
For example, if transmission is performed once a second, 1 ms
Despite obtaining the time information of the unit, the information transmission amount is about 300 bits / second.

The embodiment of the present invention is not limited to this,
It will be apparent to those skilled in the art that changes can be made without departing from the scope of the present invention. For example, the clock signal 1 kHz may be 2 kHz.

Further, it is obvious that the method of the present invention is applied not only to a transmission system for transmitting / receiving a television signal but also to a recording / reproducing system such as a VTR.

(Effects of the Invention) The effects of the method of the present invention and the receiving apparatus described above will be sequentially described below.

First, according to the method of the present invention, time information can be transmitted in a time unit of, for example, 1 ms.
^The resolution is improved about ^three times.

Next, since a resolution of the order of 1 ms can be obtained, synchronization of other multiplexed data with video and audio can be performed both in real-time type and batch type, and scalability is high.

Further, if the time is simply transmitted using one line in one field, the time unit is a field, that is, about 16 ms, despite the transmission amount of the order of 10 kbit / sec.
However, according to the method of the present invention, a resolution of 1 ms or more can be obtained even if transmission is performed by one line in one field.

Further, according to the present invention, the time information to be transmitted is only used for calibration of the time on the receiving side. For example, even if one line is multiplexed into 30 frames, a resolution of the order of 1 ms can be obtained, and the transmission capacity at this time is several hundred bits / second. the efficiently of the transmission path in the order improved by about 10 ^twice.

If the area code and the time difference are transmitted in the same packet as the transmission time information in addition to the time information, it is possible to easily cope with the time difference existing in the service area.

Furthermore, even if a video signal multiplexed on a VTR or the like is recorded and reproduced, the amount of information is small, and information can be protected by using a flywheel effect, so that reproducibility by recording is good.

Still further, the method of the present invention has a small amount of transmitted information,
Since the data transmission cycle is free, it is possible to embed in the undefined part or null part of the packet of other multiplexed data, and it is not necessary to fix the slot to be transmitted. Excellent.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing an embodiment of a transmitting-side and a receiving-side apparatus required for carrying out the method of the present invention, and FIGS. An example of a related time information generating circuit, a data packet format, and a time information reproducing circuit will be described. DESCRIPTION OF SYMBOLS 1 ... Transmission part 2,12 ... Synchronous reproduction circuit 3, ... Video inserter 4,5,14,16 ... Phase locked loop circuit 6 ... Time information generation circuit 7 ... Time information data packet generation circuit 8 Roll-off filter 11 Receiver 13 Data killer 15 Line counter 17 Digital data reproducing circuit 18 Time information data packet extracting circuit 19 Time information reproducing circuit

Claims (2)

(57) [Claims] When transmitting time information using a vertical blanking period of a television signal, a transmitting side uses a first clock signal obtained from a horizontal synchronizing signal of the television signal to operate a time information generation circuit. Drive to generate time information data, convert the time information data into a time information data packet by a second clock signal obtained from the color subcarrier of the television signal, and convert the converted time information data packet. Are multiplexed in the vertical flyback period and transmitted. On the receiving side, the second clock signal obtained from the color subcarrier of the television signal and the extraction gate signal obtained from the vertical synchronization signal and the horizontal synchronization signal are used. And extracts the time information data packet transmitted by the first clock signal obtained from the horizontal synchronization signal of the television signal. The time information synchronized with the time information on the transmitting side is reproduced by calibrating the reproduction time information data generated from the operated time information reproduction circuit with the time information data extracted from the extracted time information data packet. A time information transmission method. 2. A time information generating circuit is driven by a first clock signal obtained from a horizontal synchronizing signal of a television signal to generate time information data, and the time information data is converted from a color subcarrier of the television signal. A receiving device for converting the time information data packet into a time information data packet by the obtained second clock signal and receiving a signal transmitted by multiplexing the converted time information data packet in a vertical flyback period; Means for extracting a time information data packet transmitted by the second clock signal obtained from the color subcarrier of the signal and an extraction gate signal obtained from the vertical synchronization signal and the horizontal synchronization signal; Means for extracting time information data from a data packet, and the first clock signal obtained from a horizontal synchronization signal of a television signal And a means for generating reproduction time information data by driving the device, and a means for calibrating the reproduction time information data with the time information data, and reproducing the time information synchronized with the time information on the transmission side. Time information receiving device.