JPH0795194A - Data transmitter and data receiver - Google Patents

Abstract

PURPOSE:To send motion picture data asynchronously with a transmission clock of a transmission line without fail. CONSTITUTION:A frame pulse representing a head time of a frame of a motion picture received from a frame pulse input section 201 is counted according to a transmission clock generated by a clock generating section 203 to obtain a frame count. The frame count is mixed with motion picture data received from a data input section 202 at a data mixing section 205 and the mixed data are outputted to a transmission line 206. The bit series received via the transmission line 206 is given to a clock recovery section 207, in which the transmission clock is recovered and inputted to a data demultiplexer section 209, in which the data are demultiplexed into the motion picture data and the frame count synchronously with the transmission clock. The separated frame count is counted at a clock counter 208 based on the transmission clock to decode the interval between frame pulses. The decoded frame pulse is outputted synchronously with the motion picture data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission device and a data reception device used when transmitting data such as a moving image signal that requires real-time processing between devices.

[0002]

2. Description of the Related Art In recent years, with the progress of digital communication technology, a device for transmitting a moving image through a digital communication path is being developed. FIG. 5 shows a conventional example of a device for transmitting moving image data through a digital communication path. In FIG. 5, 50
1 is a transmitter of the device 1 which is a data transmission device, 502 is a digital transmission line, 503 is a clock recovery unit of the device 2 which is a data reception device, and 504 is a receiver.

The transmitter 501 of the device 1 outputs digital moving image data converted into a bit sequence, and the transmission line 502
It is input to the clock recovery unit 503 of the device 2 via. The clock reproducing unit 503 reproduces a clock synchronized with the bit from the input bit sequence. The input data is
In synchronization with the clock generated by the clock recovery unit 503,
It is processed by the receiver 504 and converted into the original moving image.

With such a structure, moving image data can be transmitted via a digital communication path.

[0005]

However, in the above-mentioned configuration, the reproduction processing of the moving image in the device 2 of FIG. 5 is processed by the clock synchronized with the clock used for the digital transmission on the transmission line 502. For this reason, the frame synchronization signal and the like necessary for reproducing the moving image are also produced in synchronization with the transmission clock. Therefore, the frame synchronization signal on the transmission side of the device 1 also needs to be synchronized with the transmission clock.

However, when a plurality of asynchronous video output devices are connected to this transmission line, the clock of the transmission line can be synchronized only with one of the output devices. Therefore, it becomes impossible to connect a plurality of output devices to one transmission path.

The present invention solves the problems of the conventional data transmission apparatus and data reception apparatus, and provides a data transmission apparatus and a data reception apparatus that successfully transmit moving image data asynchronous with the transmission clock of the transmission path. That is the purpose.

[0008]

In order to achieve the above object, the data transmission apparatus of the present invention, when transmitting moving picture data via a digital communication path, has a frame period of the moving picture data or about a frame period of the moving picture data. Counting means for obtaining a frame count value using a counter that counts a multiple of a number in synchronization with a clock used for transmission of the digital communication path; and data mixing means for mixing the frame count value with the moving image data. And transmitting the data generated by the data mixing means.

Further, in the data receiving apparatus of the present invention, when transmitting the moving image data via the digital communication path, the frame period of the moving image data or a multiple of the frame period is used for the transmission of the digital communication path. A receiving device for receiving data transmitted by a transmission device for transmitting a frame count value generated using a counter that is counted in synchronization with a clock together with the moving image data,
A separation unit that separates the frame count value from the transmitted data; and a frame reproduction unit that reproduces a frame period from the frame count value using a counter with the clock used for the transmission. To do.

Further, in the data transmission apparatus of the present invention, when transmitting the moving picture data through the digital communication path, the same predetermined reference value as that of the data receiving apparatus is set, and the frame period or frame cycle of the moving picture data is set. Counting means for obtaining a frame count value by counting a multiple of a divisor using a clock used for transmission of the digital communication path;
The difference value generating means for obtaining a difference value between the frame count value and the reference value, and the data mixing means for mixing the difference value with the moving image data are transmitted, and the data generated by the data mixing means is transmitted. It is characterized by doing.

Further, in the data receiving device of the present invention, when transmitting the moving image data through the digital communication path, the same predetermined reference value as that of the data receiving device is set, and the frame period or frame period of the moving image data is set. Data to be transmitted together with the moving image data by counting a multiple of a factor using a clock used for transmission of the digital communication path to obtain a frame count value and obtaining a difference value between the frame count value and the reference value. A receiving device for receiving data transmitted by a transmitting device, wherein a separation means for separating the difference value from the transmitted data, and a frame count value by adding the predetermined reference value and the difference value And a frame count value generation means for generating the frame count value with the clock used for the transmission to reproduce the frame period. It is characterized in that it has a frame reproduction unit that.

Furthermore, in the data transmission apparatus of the present invention, when transmitting moving picture data via a digital communication path, a frame period of the moving picture data or a multiple of a frame period is used for the transmission of the digital communication path. Counting means for obtaining a frame count value using a counter that counts in synchronization with a clock, and a lower digit for separating a predetermined lower digit of the frame count value obtained by the counting means to generate a lower digit value A value generating means and a data mixing means for mixing the lower digit value with the moving image data,
It is characterized in that the data generated by the data mixing means is transmitted.

Further, in the data receiving device of the present invention, when transmitting the moving image data through the digital communication path, the frame period of the moving image data or a multiple of the frame period is used for the transmission of the digital communication channel. A receiving device for receiving data transmitted by a transmitting device, which transmits the lower digit of a frame count value generated by using a counter that is counted in synchronization with a clock, together with the moving image data, wherein the transmitted data From the lower digit value, a frame count value generating means to generate a frame count value from the lower digit value, and a frame using a counter from the frame count value with the clock used for the transmission. It has a frame reproducing means for reproducing a cycle.

Further, the data transmission device of the present invention is the same as the data reception device when transmitting moving image data via a digital communication path, and is a reference expressed by a product of a predetermined integer value and a power of two. Counting means for determining a value and counting the frame period of the moving picture data or a multiple of a divisor of the frame period using a clock used for transmission of the digital communication path to obtain a frame count value; A difference value generating means for generating a difference value between the lower digit of the frame count value and the reference value, and a data mixing means for mixing the difference value obtained by the difference value generating means with the moving image data. And transmitting the data generated by the data mixing means.

Further, the data receiving apparatus of the present invention is the same as the data receiving apparatus when transmitting moving image data through a digital communication path, and is a reference expressed by a product of a predetermined integer value and a power of two. A value is determined, a frame period of the moving picture data or a multiple of a divisor of the frame period is counted using a clock used for transmission of the digital communication path to generate a frame count value, and a lower digit of the frame count value is generated. A receiving device for receiving data transmitted by a data transmission device that transmits a difference value between a value and the reference value together with the moving image data, and a separating means for separating the difference value from the transmitted data, A frame count value generating means for generating a frame count value by concatenating the difference value as a lower digit to a higher digit of a predetermined reference value, and a clock used for the transmission. It is characterized in that it has a frame reproduction means for reproducing the frame period by counting the frame count value using the clock.

[0016]

With the above configuration, the data transmission apparatus of the present invention transmits the frame count value counted by the counter that counts the frame period in synchronization with the transmission clock. As a result, even if the clock used for signal processing of the transmission device and the transmission clock are asynchronous, the receiving device of the present invention can accurately reproduce the frame period using the transmission clock. Therefore, by using the present invention, it is possible to make the signal processing clock and the transmission clock of the transmission device and the reception device asynchronous.

Further, in the data transmission device of the present invention, the reference value of the frame period common to the transmission device and the reception device is set, and the difference value from the frame count value is transmitted. Even for a moving image that is asynchronous with the transmission clock, the frame period is almost the same value as the reference value, so the difference value is very small. This makes it possible to reduce the amount of data to be transmitted.

Further, in the data transmission apparatus of the present invention, only the lower digit of the frame count value is transmitted, and the lower digit of the frame count value is received and reproduced by the receiving apparatus of the present invention, whereby the difference according to the present invention described above. Similar to the value, it is possible to reduce the amount of data to be transmitted.

[0019]

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

FIG. 1 shows an overall block diagram of a data transmission device and a data reception device of the present invention. In FIG. 1, 10
1 is a moving image input unit, 102 is an encoding unit, 103 is a transmission unit, 104 is a transmission path, 105 is a receiving unit, 106 is a decoding unit, and 107 is a moving image output unit. Video input unit 101, encoding unit 102, transmission unit 10
3 constitutes a transmission device, and the reception unit 105, the decoding unit 106, and the moving image output unit 107 constitute a reception device.

In FIG. 1, the moving image data input from the moving image input unit 101 is input to the encoding unit 102 and encoded into digital data. The encoded data that has been encoded is output to the transmission path 104 together with the information indicating the frame period of the moving image in the transmission unit 103. In the receiving unit 105, the transmission line 10
The moving image data is separated from the received data received via 4 and input to the decoding unit 106. At the same time, the receiving unit 105 separates the information indicating the frame period from the received data and reproduces the frame pulse. The decoding unit 106 uses the moving image data and the frame pulse to decode the moving image and output the moving image output unit.
Output to 107.

FIG. 2 shows a first part of the transmitting part and the receiving part according to the present invention.
2 is a block diagram of an embodiment of FIG. In FIG. 2, 201 is a frame pulse input unit, 202 is a data input unit, 203 is a clock generation unit, 204 is a clock counter of a transmission device, and 205.
Is a data mixing unit, 206 is a transmission line, 207 is a clock recovery unit,
Reference numeral 208 is a clock counter of the receiving device, 209 is a data separation unit, 210 is a frame pulse output unit, and 211 is a data output unit. In FIG. 2, the block on the left side of the transmission path 206 represents the transmission unit of the transmission apparatus, and the block on the right side of the transmission path 206 represents the reception unit of the reception apparatus. The clock counters 204 and 208 count the frame period of the moving image data or a multiple of the frame period in synchronization with the clock used for transmission on the transmission path 206 (digital communication path).

The frame pulse representing the start time of the frame of the moving image input from the frame pulse input section 201 of FIG. 2 is input to the clock counter 204. The clock counter 204 updates the counter value according to the transmission clock generated by the clock generation unit 203, and detects the input time of the frame pulse input from the frame pulse input unit. That is, the input time of the frame pulse is obtained in units of transmission clock. This is called the frame count value. The frame count value is mixed by the data mixing unit 205 with the moving image data input from the data input unit 202. The bit sequence obtained by mixing is output to the transmission path 206 in synchronization with the transmission clock generated by the clock generation unit 203.

The bit sequence input to the data receiving device via the transmission path 206 is first input to the clock recovery unit 207 to recover the transmission clock. Next, the clock recovery unit 207
The transmission clock regenerated in (1) is input to the data separation unit 209, and is separated into the moving image data and the frame count value in synchronization with the transmission clock. The separated moving image data is output to the data output unit 211, and the frame count value is input to the clock counter 208. The clock counter 208 counts the input frame count value with the transmission clock and restores the frame pulse interval. The restored frame pulse is output to the frame pulse output unit 210 in synchronization with the moving image data.

In this way, in the first embodiment, the frame interval used in the data transmission device can be restored in the data reception device. Further, in the configuration of FIG. 2, the signal processing of the moving image processing need not be synchronized with the transmission clock used for digital transmission. Therefore, it is possible to transmit moving image data that is asynchronous with the transmission clock. Therefore, it is possible to simultaneously transmit a plurality of asynchronous moving image data.

FIG. 3 shows a second part of the transmitter and the receiver according to the present invention.
2 is a block diagram of an embodiment of FIG. In FIG. 3, reference numeral 301 is a frame pulse input unit, 302 is a reference value input unit, 303 is a data input unit, 304 is a clock generation unit, 305 is a clock counter of a transmission device, 306 is a difference unit, and 307 is a data mixing unit. , 30
8 is a transmission line, 309 is a clock recovery unit, 310 is a clock counter of the receiving device, 311 is an adder, 312 is a data separation unit,
313 is a frame pulse output section, 314 is a reference value input section, 31
5 is a data output section. In FIG. 3, the block on the left side of the transmission path 308 represents the transmission section of the transmission device, and the transmission path 30
The block on the right side of 8 represents the receiving unit of the receiving device. The clock counters 305 and 310 count the frame period of video data or a multiple of the frame period in synchronization with the clock used for transmission on the transmission line 308 (digital communication line).

The frame pulse representing the start time of the frame of the moving image input from the frame pulse input section 301 of FIG. 3 is input to the clock counter 305. The clock counter 305 counts the intervals of the above frame pulses with the transmission clock generated by the clock generation unit 304. This gives the frame count value. The frame count value is subtracted from the reference value input from the reference value input unit 302 by the differentiator 306. The difference value obtained thereby is mixed in the data mixing unit 307 with the moving image data input from the data input unit 303. The bit sequence obtained by mixing is output to the transmission path 308 in synchronization with the transmission clock generated by the clock generation unit 304.

The bit sequence input to the data receiving device via the transmission path 308 is first input to the clock recovery unit 309 to recover the transmission clock. Next, the clock recovery unit 30
The transmission clock reproduced in 9 is input to the data separation unit 312, and the moving image data and the above difference value are separated in synchronization with the transmission clock. The separated moving image data is output to the data output unit 315, and the difference value is input to the adder 311. The adder 311 adds the difference value and the reference value input from the reference value input unit 314 to obtain a frame count value and inputs the frame count value to the clock counter 310. The clock counter 310 counts the input frame count value with the transmission clock and restores the frame pulse interval. The restored frame pulse is sent to the frame pulse output section 31.
Output to 3 in sync with video data.

As described above, in the second embodiment, the frame
When transmitting the count value, only the difference value from the reference value known by both the transmitting device and the receiving device is transmitted. Even in the case of asynchronous TV signals in the normal TV system, the difference from the reference value can be kept within 1%. Therefore, by transmitting only the difference value, the data for transmitting the frame interval is transmitted. It is possible to significantly reduce the amount. Further, even when the frame interval is different depending on the TV system to be transmitted, the amount of data to be transmitted can be controlled to be constant if it is a difference value from the reference value.

FIG. 4 shows a third part of the transmitter and receiver according to the present invention.
2 is a block diagram of an embodiment of FIG. In FIG. 4, 401 is a frame pulse input unit, 402 is a data input unit, 403 is a clock generation unit, 404 is a clock counter of the transmission device, and 405.
Is a lower digit selection unit, 406 is a data mixing unit, 407 is a transmission line, 40
Reference numeral 8 is a clock reproduction unit, 409 is a clock counter of the receiving device, 410 is a connection unit, 411 is a data separation unit, 412 is a frame pulse output unit, 413 is an upper digit input unit, and 414 is a data output unit. In FIG. 4, the block on the left side of the transmission path 407 represents the transmission section of the transmission device, and the block on the right side of the transmission path 407 represents the reception section of the reception device. The clock counters 404 and 409 count the frame period of video data or a multiple of the frame period in synchronization with the clock used for transmission on the transmission line 407 (digital communication line).

The frame pulse representing the start time of the frame of the moving image input from the frame pulse input section 401 of FIG. 4 is input to the clock counter 404. The clock counter 404 counts the above frame pulse intervals with the transmission clock generated by the clock generator 403. This gives the frame count value. A value represented by a specific number of lower digits of the frame count value is selected by the lower digit selector 405. The lower digit value thus obtained is mixed in the data mixing unit 406 with the moving image data input from the data input unit 402. The bit sequence obtained by mixing is output to the transmission path 407 in synchronization with the transmission clock generated by the clock generation unit 403.

The bit sequence input to the data receiving device via the transmission path 407 is first input to the clock recovery unit 408 to recover the transmission clock. Next, the clock recovery unit 40
The transmission clock reproduced in 8 is input to the data separation unit 411, and the moving image data and the lower digit value are separated in synchronization with the transmission clock. The separated moving image data is output to the data output unit 414, and the lower digit value is input to the connection unit 410. The concatenation unit 410 concatenates the frame count value with the lower digit value as the lower digit, and the value input from the upper digit input unit 413 as the upper digit to derive the frame count value.
Enter in 409. The clock counter 409 counts the input frame count value with the transmission clock to restore the frame pulse interval. The restored frame pulse is output to the frame pulse output unit 412 in synchronization with the moving image data.

As described in the second embodiment, in a normal moving image, the difference between the actual frame period and the reference value of the frame period is a very small value. Therefore, even if only the lower digit of the frame counter value is transmitted, the frame period can be reproduced from the lower digit value and the reference value of the frame period.

Further, the reference value of the frame period described above is
The device can be further simplified by using a number represented by a product of a simple integer and a large power of two. In this case, in the value in which the reference value is represented by a binary number, the upper digit is a specific binary number and the lower digits are all represented by 0. As a result, when the clock counter unit 404 of the data transmission device shown in FIG. 4 sets the reference value so that the upper digit of the value obtained by counting the frame intervals matches the upper digit of the reference value, The lower digit of the count value can be used as it is as a difference value from the reference value.

In the following, the transmission device and the reception device of the present invention are used to transmit a television signal (hereinafter referred to as a TV signal) of a 525/60 system or a 625/50 system at about 60 Mbit / s.
An example of transmission using the ec digital communication path will be described. First, the reference value of the frame interval for the 525/60 system and the 625/50 system is set as follows with a clock of 60 MHz.

[0036]

[Table 1]

By setting the reference value to such a value, the reference value can be separated into the upper digit binary number and the lower digit represented by all zeros. Therefore, if the frame interval that can be transmitted is [reference value] + α (0 ≦ α <2 ¹⁵ ), the upper digit (lower 1
(Except for 5 bits) always matches the upper digit of the reference value. Therefore, the value of α becomes the difference value as it is. In the receiving device, the frame clock number can be reproduced only by replacing the lower digit (lower 15 bits) of the reference value with the transmitted difference value (α).

Further, the normal clock number counting is executed by using a counter. However, as above
Since the upper digit of the count number is the same in both the transmitting device and the receiving device, it is possible to configure the clock number counting unit only by the counter excluding the upper digit by using the data of the signal processing unit of the moving image. .

In the above example, the transmission clock is 60
At MHz, the reference value of the frame period is 525/60
In the case of the TV signal, the description is made as (30 × 2 ¹⁵ × n) clocks, and when the reference value of the frame period is 625/50 TV signals, the explanation is made as (36 × 2 ¹⁵ × n) clocks. When the frequency is approximately (30 × n) MHz, the reference value of the frame period is 525/60 television signal or 1125/60 television signal or 10
In the case of a 50/60 television signal (30 × 2 ¹⁵ ×
n) a clock, or (3 in the case of a 625/50 television signal or a 1250/50 television signal)
6 × 2 ¹⁵ × n) clock may be used.

As described above using each embodiment, the transmission apparatus of the present invention can transmit the frame interval to the reception apparatus with the accuracy of the transmission clock. Therefore, if the accuracy of the frame interval does not need to be high, it is possible to reduce the accuracy of the number of frame clocks to be transmitted and the difference value (reduce the number of digits) to reduce the transmission amount and circuit scale. Is.

The present invention is a system that can be used for any data that requires real-time transmission other than moving images, and its transmission system, transmission frequency, device configuration, etc. are not limited to those shown in this embodiment. Various implementation methods can be applied, and of course processing by software having the functions of the hardware configuration shown in this embodiment is also possible.

[0042]

As described above, in the data transmission apparatus of the present invention, even if the clock used for signal processing of the transmission apparatus and the transmission clock are asynchronous, the receiving apparatus can accurately reproduce the frame period. Become. Therefore, the signal processing clock of the transmission device and the reception device can be made asynchronous with the transmission clock, and a plurality of asynchronous transmission devices can be simultaneously connected.

Further, in the present invention, for a predetermined reference value,
By transmitting only the difference value with the frame count value, the difference value is very small because the frame period is almost the same value as the reference value even for moving images that are asynchronous with the transmission clock. It is possible to significantly reduce the amount of data to be transmitted.

Further, according to the present invention, by transmitting only the lower digit of the frame count value, the transmission amount of the frame count value can be reduced, and the lower digit of the frame count value and the difference value can be the same value. By setting to 1, the addition and subtraction circuits are not required for both the transmission device and the reception device, and the circuit scale can be reduced. Further, since the number of digits actually required for transmitting and receiving the frame count value can be reduced, it is possible to reduce the number of digits of the clock counter.

As described above, according to the present invention, a plurality of asynchronous moving image data can be transmitted with only a slight increase in the amount of data. In addition, the increase in the scale of equipment is small,
Its practical effect is very large.

[Brief description of drawings]

FIG. 1 is an overall block diagram of a data transmission device and a data reception device of the present invention.

FIG. 2 is a block diagram of a first embodiment of a transmission unit of a data transmission device and a reception unit of a data reception device of the present invention.

FIG. 3 is a block diagram of a second embodiment of the transmission unit of the data transmission device and the reception unit of the data reception device of the present invention.

FIG. 4 is a block diagram of a third embodiment of the transmission unit of the data transmission device and the reception unit of the data reception device of the present invention.

FIG. 5 is a block diagram of a conventional data transmission device and data reception device.

[Explanation of symbols]

 203,304,403 Clock generation unit 204,404 Clock counter 208,305,310,409 Clock number counting unit 306 Difference unit 405 Lower digit selection unit 205,307,406 Data mixing unit 207,309,408 Clock recovery unit 311 Adder 410 Concatenating unit 209,312,411 Data separating unit

Claims (10)

[Claims] 1. When transmitting moving image data through a digital communication path, a frame period of the moving image data or a multiple of a frame period is counted in synchronization with a clock used for transmission through the digital communication path. A counter that obtains a frame count value using a counter; and a data mixing unit that mixes the frame count value with the moving image data, and transmits the data generated by the data mixing unit. Data transmission device. 2. When transmitting moving image data through a digital communication path, a frame period of the moving image data or a multiple of a frame period is counted in synchronization with a clock used for transmission of the digital communication path. A receiving device for receiving data transmitted by a transmission device for transmitting a frame count value generated by using a counter together with the moving image data, wherein the separating device separates the frame count value from the transmitted data. And a frame reproducing means for reproducing a frame period from the frame count value using a counter with the clock used for the transmission. 3. When transmitting moving image data through a digital communication path, the same predetermined reference value as that of the data receiving device is set, and a frame period of the moving image data or a multiple of a frame period is calculated by the digital communication. Counting means for obtaining a frame count value by counting using a clock used for transmission on a road, difference value generating means for obtaining a difference value between the frame count value and the reference value, and the difference value for the moving image data. And a data mixing means for mixing
A data transmission device, which transmits the data generated by the data mixing means. 4. When transmitting moving picture data via a digital communication path, the same predetermined reference value as that of the data receiving device is set, and a frame period of the moving picture data or a multiple of a frame period is multiplied by the digital communication. The frame count value is obtained by counting using the clock used for the transmission of the data, the difference value between the frame count value and the reference value is obtained, and the data transmitted by the data transmission device which is transmitted together with the moving image data is transmitted. A receiving device for receiving, a separation means for separating the difference value from the transmitted data, and a frame count value generation for adding the predetermined reference value and the difference value to generate a frame count value. Means and a frame reproducing means for reproducing the frame period by counting the frame count value with the clock used for the transmission. Data receiving apparatus according to claim. 5. When transmitting moving image data through a digital communication path, a frame period of the moving image data or a multiple of a frame period is counted in synchronization with a clock used for transmission through the digital communication path. Counting means for obtaining a frame count value using a counter; lower digit value generating means for separating a predetermined lower digit of the frame count value obtained by the counting means to generate a lower digit value; and the lower digit A data transmission device comprising: a data mixing unit for mixing a value with the moving image data, and transmitting the data generated by the data mixing unit. 6. When transmitting moving image data via a digital communication path, a frame period of the moving image data or a multiple of a frame period is counted in synchronization with a clock used for transmission of the digital communication path. A receiving device for receiving data transmitted by a transmission device for transmitting the lower digit of a frame count value generated by using a counter together with the moving image data, and separating the lower digit value from the transmitted data. A separating means, a frame count value generating means for generating a frame count value from the lower digit value, and a frame reproducing means for reproducing a frame period from the frame count value using a counter with the clock used for the transmission. A data receiving device comprising: 7. When transmitting moving picture data through a digital communication path, a reference value which is the same as that of the data receiving apparatus and which is represented by a product of a predetermined integer value and a power of 2 is set, and the moving picture data of the moving picture data is set. Counting means for obtaining a frame count value by counting a frame period or a multiple of a frame period using a clock used for transmission of the digital communication path, and a lower digit of the frame count value obtained by the counting means Difference value generating means for generating a difference value between the value of and the reference value, and a data mixing means for mixing the difference value obtained by the difference value generating means with the moving image data. A data transmission device, which transmits generated data. 8. When transmitting moving picture data through a digital communication path, a reference value which is the same as that of the data receiving apparatus and which is represented by a product of a predetermined integer value and a power of 2 is set, and the moving picture data of the moving picture data is set. A frame cycle value or a multiple of a frame cycle is calculated using a clock used for transmission of the digital communication path to generate a frame count value, and the difference between the lower digit value of the frame count value and the reference value. A receiving device that receives data transmitted by a data transmission device that transmits a value together with the moving image data, and a separating means that separates the difference value from the transmitted data, and a high-order digit of the predetermined reference value. A frame count value generating means for generating a frame count value by concatenating the difference value as a lower digit, and the frame count value by the clock used for the transmission. Data receiving apparatus characterized by having a frame reproduction means for reproducing the frame period and count. 9. When the transmission clock is approximately (30 × n) MHz and the frame period reference value is a 525/60 television signal, a 1125/60 television signal or a 1050/60 television signal, (30 × 2 ¹⁵
Xn) clock, and in the case of a 625/50 television signal or a 1250/50 television signal (36
× 2 ¹⁵ × n) clocks.
Alternatively, the data transmission device according to any one of claims 3 or 5 or 7. 10. The method according to claim 1, wherein the frame count value, the difference value, or the lower digit value to be transmitted is reduced in accuracy before being transmitted. The data transmission device described in 1.