JP3389747B2 - Transmission device, transmission recording device, and reproduction transmission device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission device for transmitting digital signals, a transmission recording device and a reproduction transmission device.

[0002]

2. Description of the Related Art In recent years, development of a high-speed digital interface for transmitting digital signals in real time has been progressing, and particularly eye-to-eye (IEEE) 1
The 394 standard serial bus is expected as an interface suitable for multimedia transmission centered on images, because of its high rate and the advantage that simultaneous real-time transmission and asynchronous transmission can be performed.

FIG. 3 shows the configuration of a transmitter of a conventional digital signal transmission device. Here, for example, the MPEG2 signal is I
It is assumed that the data is transmitted by the EEE1394 transmission device.

In FIG. 3, 1 is a transmitter and 2 is MPEG.
2 decoder box, 3 buffer, 4 arrival timing acquirer, 5 first time stamp generator, 30 time stamp adder, 9 cycle time register (C
Cycle Time Register (CTR), 1
0 indicates a transmission packet converter.

The first time stamp is a clock C with which the time is adjusted between the devices connected to the transmission path.
It is generated based on the count value of TR9.

From the MPEG2 decoder box 2 to each MP
The arrival timing acquisition unit 4 acquires the arrival timing when the EG2 data packet is output to the transmitter 1.

In the first time stamp generator 5, the CTR
The value of 8 is latched at the arrival timing, and a transmission time stamp is generated by adding the count value of the maximum delay time of a predetermined transmitter to the receiver. The input data packet is accumulated in the buffer, and then the time stamp adder 30
The transmission packet is added with a transmission time stamp to be converted into a source packet, and the transmission packet converter 10 further converts the source packet into a transmission packet in which a plurality of source packets are collected. The transmission packet may be converted by dividing the source packet into some according to the rate or the like.

The form of the source packet at this time is shown in FIG. Transmission of IEEE 1394 is 4 bytes (byte)
It is a unit, and the source packet header has a size of 4 bytes. The first time stamp has the same format as the lower 20 bits of the CTR value, and the remaining 12 bits are reserved bits.

FIG. 4 shows the configuration of a receiver of a conventional digital signal transmission device and a recorder connected to the receiver.

In FIG. 4, 19 is a transmission packet converter, 20 is a receiver, 21 is a recording device, 3 is a buffer, and 2 is a recording device.
2 is a time stamp separator, 23 is a read timing generator, 4 is an arrival timing acquirer, 40 is a PCR extractor, 41 is a 27 MHz PLL, 42 is a counter, 43 is a recording time stamp generator, and 9 is a cycle time register (CTR). ), 26 is a recording signal processing circuit, and 27 is a recording medium.

The count value of the cycle time register (CTR) 8 is adjusted by each device connected to the transmission line.

The transmission packet converter 19 converts the transmission packet arriving at the receiver into a source packet.

The first time stamp separator 22 separates the transmission time stamp from the source packet, and the read timing generator 23 outputs the read signal to the buffer at the timing when the obtained transmission time stamp value and the count value of CTR8 match. send. As a result, a data packet is output from the buffer at a timing at which the delay amount between the input time to the transmitter and the output time from the receiver becomes constant.

In the recorder 21, the MPEG2 data in the data packet is analyzed by the PCR extractor 40 and the program clock reference (ProgramClock) is executed.
Obtain timing information called Reference (PCR). The 27 MHz PLL is a system clock of MPEG2, and is also an operation clock of the recording device.
It has a Hz oscillator and a counter 42 synchronized with the clock, and compares the obtained PCR value and the count value to correct the clock to restore the 27 MHz clock at the time of encoding the input MPEG2 signal. . This makes it possible to obtain an accurate operating frequency that absorbs transmission jitter.

The arrival timing acquisition unit 4 detects the arrival timing of each data packet. Recording time stamp
The generator 43 generates 27 MHz according to the arrival timing of the data packet obtained by the arrival timing acquisition unit 4.
Latch the counter and generate a recording time stamp.

The recording time stamp corresponding to each data packet is input to the recording signal processing circuit 26, is subjected to processing such as formatting, error correction coding and modulation suitable for the recording medium and is recorded in the recording medium 27. .

[0017]

However, when the recording device is connected to the receiver of the transmission device to record the digital signal, the recording time stamp is generated as shown in the PCR extractor 40. Therefore, it is necessary to analyze the inside of the digital signal to extract the information for restoring the operating frequency, which has a drawback that the amount of hardware on the receiving and recording side becomes large.

In view of the above points, the present invention has an object to provide a transmission device and a recording device which do not require internal analysis of digital signals.

[0019]

In order to solve the above problems, the transmission apparatus of the present invention obtains a timing at which a receiver should output a data packet included in a transmission packet received from a transmission line, A first time stamp generating means for generating and outputting one time stamp, a counter for counting up at a predetermined frequency, and a count value of the counter for latching the count value of the counter at the timing when the data packet arrives at the digital signal transmission device. Second time stamp generating means for outputting as a time stamp, time stamp adding means for adding the first time stamp and the second time stamp to the data packet and outputting as a source packet, and transmitting the source packet Transmission means for transmitting to the transmission line using a packet. .

Further, the transmission recording apparatus of the present invention includes a first time stamp, which is information indicating the timing at which the data packet included in the transmission packet received by the receiver from the transmission path should be output, and the data transmitted to the transmitter. A second time stamp, which is information indicating the arrival timing of a packet with a count value of a predetermined frequency, is added to the data packet to form a source packet, and the source packet is received and recorded in the transmission packet format. The digital signal transmission recording apparatus according to the present invention is characterized by comprising recording means for recording the data packet and the second time stamp together on a recording medium.

Alternatively, by using a counter that counts up at a recording frequency, which is a frequency at which the digital transmission recording apparatus operates based on recording, the first time stamp and the counter, reproduction output from a recording medium is performed. And a recording time stamp generating means for generating a recording time stamp which is timing information to be recorded, and a recording means for recording the data packet and the recording time stamp together on the recording medium.

The reproducing / transmitting apparatus of the present invention further comprises an extracting means for extracting the recording time stamp from the recording medium on which the recording time stamp which is the timing information to be reproduced and output from the recording medium and the data packet are recorded together. A first time stamp generating means for obtaining a timing at which the data packet included in the data packet included in the transmission packet received by the receiver from the transmission path should be output, and generating and outputting the first time stamp; and the recording time. A time stamp adding means for adding a stamp as a second time stamp to the data packet together with the first time stamp and outputting it as a source packet, and transmitting the source packet to the transmission path using the transmission packet. It is characterized by having a transmitting means.

[0023]

With the above construction, the present invention makes it possible to provide a transmission device and a recording device which do not require internal analysis of digital signals.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of the transmitter of the digital signal transmission apparatus according to the first embodiment of the present invention.

Here, the MPEG2 signal is transferred to IEEE139.
It is assumed that data is transmitted by four transmission devices.

In FIG. 1, 1 is a transmitter and 2 is MPEG.
2 decoder box, 3 buffer, 4 arrival timing acquirer, 5 first time stamp generator, 6 second time stamp generator, 7 time stamp adder, 9 cycle time register (CTR), 10 Indicates a transmission packet converter.

The first time stamp is generated based on the count value of the cycle time register (CTR) 9, which is a clock whose time is adjusted between the devices connected to the transmission path.

From the MPEG2 decoder box 2 to each MP
The arrival timing acquisition unit 4 acquires the arrival timing when the EG2 data packet is output to the transmitter 1.

In the first time stamp generator 5, the CTR
The value of 9 is latched at the arrival timing, and the count value of the maximum delay time of a predetermined transmitter-receiver is further added to generate the transmission time stamp which is the first time stamp.

Further, in the second time stamp generator 6,
27MHz existing in MPEG2 decoder box 2
The value of the counter 11 of the PLL 8 is latched at the arrival timing to generate the recording time stamp which is the second time stamp.

The input data packet is stored in a buffer, and then a transmission time stamp and a recording time stamp are added by the time stamp adder 7 to be converted into a source packet, and the transmission packet converter 10 is further added.
Is converted into a transmission packet by.

The form of the source packet at this time is shown in FIG. The transmission of IEEE1394 is in units of 4 bytes,
The source packet header has a size of 4 bytes. The transmission packet has the same format as the lower 20 bits of the CTR value, and the recording time stamp has a count value of 12 bits of 27 MHz.

For example, the recording time stamp is MPEG2.
The system clock is 27 MHz, which is the operating frequency of the signal processing circuit of the deck, and the transmission time stamp is the frequency of the CTR of IEEE 1394.
It is assumed that it is 576 MHz.

The use of 27 MHz as the recording time stamp is easy to generate because it always has a 27 MHz clock on the decoder box side, and it is possible to maintain high timing accuracy when finally returning to the decoder. Is effective in. Using 24.576 MHz as a transmission time stamp is effective because the lower bits of CTR can be used as they are.

FIG. 2 shows the configuration of a digital signal transmission recording apparatus according to the second embodiment. 2, 19 is a transmission packet converter 20 the receiver, 21 a recording device, 3 denotes a buffer, 22 time stamp separator 23 reads the timing generator, the 2 4 second time stamp separator 25 Is a high-order bit generator, 9 is a cycle time
e Register (CTR), 26 is a recording signal processing circuit, and 27 is a recording medium.

The operation of the receiver 20 will be described. The transmission packet converter 19 converts the transmission packet arriving at the receiver into a source packet.

The first time stamp separator 22 separates the transmission time stamp from the source packet, and the read timing generator 23 matches the value of the transmission time stamp which is the first time stamp obtained with the count value of the CTR8. A read signal is sent to the buffer at the timing. As a result, a data packet is output from the buffer at a timing at which the delay amount between the input time to the transmitter and the output time from the receiver becomes constant.

Next, the operation of the recording machine 21 will be described.
The second time stamp separator 24 separates the second time stamp added to the data packet.

The separated second time stamp is input to the recording signal processing circuit 26 together with the data packet,
The data is recorded on the recording medium 27 after being subjected to processing suitable for the recording medium, such as formatting, error correction coding, and modulation.

At this time, when the size of the second time stamp in the source packet and the size of the recording time stamp to be recorded on the recording medium are the same, the first method is to record the second time stamp as it is. May be recorded in a recording medium as.

If the size of the second time stamp in the source packet is smaller than the size of the recording time stamp recorded on the recording medium, the first method is the first method.
The upper bits of the recording time stamp may be generated from the transmission time stamp which is the time stamp of.

For example, a count value of 21 bits of 27 MHz is used as a recording stamp to be recorded on a recording medium, and only the lower 8 bits of 27 MHz are second in a source packet.
Is added as a time stamp of, the upper 13 bits at the time of recording, that is, 1,2700000
It is necessary to express a multiple of 0 × 256 = 9.48247 × 10 ⁻⁶ seconds.

On the other hand, the transmission time stamp is 1/2
4576000 = 4.06901 × 10 It is a numerical value that counts up every ^-8 seconds. Since the transmission interval is 100 milliseconds or less, the upper 13 bits of the recording time stamp can be generated from the count value of the transmission time stamp. It is possible. The 27th MHz 9th bit is 24.576
Count up by 1 at 233.017 counts of MHz. Normally, 233 counts and 0.017 fractions may be accumulated so that the count is increased to 234 counts once every about 60 cycles.

FIG. 5 shows the configuration of a digital signal transmission recording apparatus according to the third embodiment. In FIG. 5, 19 is a transmission packet converter, 20 is a receiver, 50 is a recorder, 3 is a buffer, 22 is a first time stamp separator, 23 is a read timing generator, 54 is an arrival timing acquirer, and 24 is Second time stamp separator, 51 is recording time stamp generator, 52 is 27 MHz PLL, 53 is 2
7MHz counter, 9 is cycle time register (C
TR), 26 is a recording signal processing circuit, and 27 is a recording medium.

The operation of the receiver 20 is similar to that of the second embodiment. Next, the operation of the recorder 50 will be described.

The second time stamp separator 24 separates the recording time stamp added to the data packet. The 27 MHz PLL 52 has a 27 MHz oscillator and a counter 53 that is synchronized with the clock inside.
The time stamp value and the count value of the counter 23 are compared to correct the clock so that the input MP
The 27 MHz clock at the time of encoding the EG2 signal can be restored without extracting the PCR from inside the signal, and an accurate operating frequency that absorbs transmission jitter can be obtained.

The arrival timing acquisition unit 54 detects the arrival timing of each data packet at the recorder 50, as in the case of 4 in the first embodiment.

The recording time stamp generator 51 latches the count value of the 27 MHz counter 53 according to the arrival timing of the data packet obtained by the arrival timing acquisition unit 54, and generates the recording time stamp.

The recording time stamp corresponding to each data packet is input to the recording signal processing circuit 26, and is subjected to processing such as formatting, error correction coding and modulation suitable for the recording medium and recorded on the recording medium 27.

FIG. 8 shows the configuration of a digital signal reproducing / transmitting apparatus according to the fourth embodiment. In FIG. 8, 80 is a transmitter, 81 is a reproducer, 3 is a buffer, 4 is an arrival timing acquisition device, 5 is a first time stamp generator, 7 is a time stamp adder, and 9 is a cycle time register (Cy).
cle Time Register), 10 is a transmission packet converter, 82 is a second time stamp separator, 83
Is a high-order bit remover, 84 is a reproduction signal processing circuit, and 27 is a recording medium.

The arrival timing acquisition unit 4 acquires the arrival timing when each MPEG2 data packet is output from the reproducing unit 81 to the transmitter 80. The first time stamp generator 5 latches the value of the CTR 9 at the arrival timing and further adds the count value of the maximum delay time of a predetermined transmitter to the receiver to generate a transmission time stamp.

Further, in the second time stamp separator 82, the recording time stamp which is present together with the data packet in the data reproduced from the recording medium 27 and subjected to the processing such as demodulation and error correction by the reproduction processing circuit 832. To separate. Recording medium 27 If the recording medium is recorded by the first method of the second embodiment, that is, if the recording time stamp has the same number of bits as that transmitted, the separated recording time stamp is It is sent to the time stamp adder 7 together with the transmission time stamp as the time stamp of 2. The reproduced data packet is stored in a buffer, and then a transmission time stamp and a recording time stamp are added by a time stamp adder 7 to be converted into a source packet, and further converted by a transmission packet converter 10 into a transmission packet and transmitted. It

In the embodiment described above, the sizes of the data packet, the source packet, the transmission packet,
Bit arrangement is arbitrary. The number of bits of the first time stamp and the second time stamp is arbitrary.

The arrangement of the data packet and the recording time stamp on the recording medium and the number of bits are also arbitrary.

[0056]

As described above, according to the present invention,
A transmission device and a recording device that do not require internal analysis of digital signals can be obtained, and hardware and cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a transmitter of a digital signal transmission device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a digital signal transmission / recording device according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a transmitter of a digital signal transmission device in a conventional example.

FIG. 4 is a block diagram of a digital signal transmission / recording device in a conventional example.

FIG. 5 is a configuration diagram of a digital signal transmission / recording apparatus according to a third embodiment of the present invention.

FIG. 6 is a diagram showing the contents of a source packet according to the first embodiment of the present invention.

FIG. 7 is a diagram showing the contents of a source packet in a conventional example.

FIG. 8 is a configuration diagram of a digital signal reproducing / transmitting device according to a fourth embodiment of the present invention.

[Explanation of symbols]

1 Transmitter 2 Decoder Box 3 Buffers 4 and 54 Arrival Timing Acquisition Device 5 First Time Stamp Generator 6 Second Time Stamp Generator 7 Time Stamp Adder 8 27MHz PLL 9 Cycle Time Register (Cycle Time)
Register) 10, 19 Transmission packet converter 20 Receiver 21, 50 Recording device 22 First time stamp separator 23 Read timing generator 24 Second time stamp separator 25 Upper bit generator 26 Recording signal processor 27 Recording medium 50 recording time stamp generator 11, 52 counter

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-7-46591 (JP, A) JP-A-8-79705 (JP, A) JP-A-9-511368 (JP, A) JP-A-11- 507790 (JP, A) Special table H11-507755 (JP, A) Special table H9-504884 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 12/56 H04N 7 /twenty four

Claims (12)

(57) [Claims] 1. A first time stamp generating means for obtaining a timing at which a receiver should output a data packet included in a transmission packet received from a transmission path, and generating and outputting a first time stamp, and a predetermined frequency. A counter that counts up with, a second time stamp generation unit that latches the count value of the counter at the timing when a data packet arrives at the digital signal transmission device, and outputs the second time stamp as the second time stamp, and the first time stamp. It has a time stamp adding means for adding the second time stamp to the data packet and outputting it as a source packet, and a transmitting means for transmitting the source packet to the transmission path using the transmission packet. Transmission equipment. 2. The transmission device according to claim 1, wherein the predetermined frequency is generated based on a frequency used when decoding the data packet. 3. The transmission device according to claim 1, wherein the predetermined frequency is generated based on a frequency used when recording the data packet on the recording medium. 4. The transmission device according to claim 1, wherein the first time stamp is generated based on a frequency used when transmitting the digital signal. 5. The first time stamp is generated based on a clock whose time is adjusted between the devices connected to the transmission path. The transmission device according to the item. 6. A first time stamp, which is information indicating a timing at which a receiver should output a data packet included in a transmission packet received from a transmission path, and a timing at which the data packet arrives at the transmitter are predetermined. A second time stamp, which is information indicated by a frequency count value, is added to the data packet to form a source packet,
A digital signal transmission recording apparatus for receiving and recording the source packet in the transmission packet format, comprising: a recording unit for recording the data packet and the second time stamp together on a recording medium. Transmission recording device. 7. The transmission recording apparatus according to claim 6, further comprising a generation unit that generates the upper bits of the second time stamp based on the first time stamp. 8. A first time stamp, which is information indicating the timing at which a receiver should output a data packet included in a transmission packet received from a transmission path, and a timing at which the data packet arrives at the transmitter are predetermined. A second time stamp, which is information indicated by a frequency count value, is added to the data packet to form a source packet,
Wherein a digital signal transmission recording apparatus the source packet receiving and recording in the transmission packet format, a counter the digital transmission recording apparatus counts up at a recording frequency which is the frequency that operates based on the time of recording, the Recording time stamp generating means for generating a recording time stamp, which is timing information to be reproduced and output from a recording medium, using the first time stamp and the counter, and the recording together with the data packet and the recording time stamp. A transmission recording apparatus having recording means for recording on a medium. 9. The transmission recording apparatus according to claim 8, wherein the recording time stamp generating means latches the value of the counter at the timing indicated by the first time stamp. 10. The recording frequency generating means for generating a recording frequency based on the value of the second time stamp and the timing indicated by the first time stamp, according to claim 6, 7 or 8 or 9. Transmission recorder. 11. An extracting unit for extracting a recording time stamp from the recording medium in which a recording time stamp, which is timing information to be reproduced and output from the recording medium, and a data packet are recorded together, and a receiver received from a transmission line. A first time stamp generating unit that obtains a timing to output a data packet included in a data packet included in a transmission packet and generates and outputs a first time stamp, and the recording time stamp as a second time stamp. A time stamp adding means for adding to the data packet together with the first time stamp and outputting it as a source packet, and a transmitting means for transmitting the source packet to the transmission path using the transmission packet. Playback transmission device. 12. The reproduction / transmission apparatus according to claim 6, wherein the time stamp adding means deletes the high-order bits of the recording time stamp and adds it as a second time stamp.