TW401695B - Method of and apparatus for recording digital television signals - Google Patents

Abstract

A video recorder comprises an input (14) for receiving a digital television signal which is fed via an interface circuit (15) to a buffer RAM and error correction circuit (16). A control and timing circuit (13) passes this signal from the buffer RAM (16) to a tape encoder (7) which converts the code n-bits at a time into a 2"" level code thus reducing the data rate by 1/n. This reduces the data rate to one which can be recorded by a VHS recorder. On replay the inverse operation is carried out using the tape decoder (19), buffer RAM and error correction circuit (16) and output interface (20) to provide a replayed digital television signal at an output 21. A further embodiment includes a digital video encoder/decoder to enable analogue television signals to be recorded in digital form.

Description

4〇1695 V. Description of the Invention (1) The present invention relates to a method and device for recording digital television signals. The invention also relates to a method and apparatus for recording many television signals simultaneously. In one particular feature, the present invention relates to a video recorder utilizing standard analog video recorder components. There is currently great interest and many suggestions for digital television transmission from earth transmitters and satellites. But there are still many analog receivers' so it will take several years for the digital TV interface to be replaced to replace the existing established receiver base. Therefore, 'video recorders have great potential in the market' because they can record and / or play back analog and digital signals. Proposals for video recorders to record and / or play back analog and political television signals have been disclosed in EP-A-060 1 963. This patent document particularly discloses a system for a video cassette recorder that can record and reproduce analog signals and audio signals, and can be used for HDTV for digital video and audio signals. The head drum rotations can be determined to be different from each other, depending on the selected mode, that is, the digital or analog signal recording / reproduction mode 'hence' the digital signal having a recording bandwidth different from the analog signal can be recorded from a conventional analog tape And regeneration. Another proposal published in US-A-5 335 125 discloses a video tape recorder that can record a normal-definition video signal while broadcasting the same program in a conventional broadcast system and a high-resolution system, and It has high-resolution video signals with higher image quality than normal image quality. The common video signal is recorded in a traditional analog signal format with a track width larger than the standard mode. The EP mode head is recorded at the tape feed speed of the normal mode, while the high-resolution video signal is digitally transmitted on the rotating drum.

Ih \ y87 \ 54650. Ptd Page 5 401695 V. Description of Invention (3) Imagine in British Patent Application No. 9605 6 1 4. 8 (PHB 340 56). It can be coded through θ, and the data is a multi-level quasi-code. In the specific example, the code is 4 digits: on the -VHS video recorder, thus reducing the digital data stream of the original telex video image: The quasi-code may contain a multi-level quasi-signal with two amplitude bits and may contain many phases = signs = together, so that more bits can be used in each data period. Success-The multi-level code may have four levels, so its data rate-half of the data rate of the data stream. The digital television signal for the received digital seconds can be equal to two; 5 million bits / The present invention can also be connected: 2: 2 video recorders to record. ^ ^ ° ', the method can use a digital data stream to generate a more expensive TV signal from a recording, the playback device is slower than the data speed of the TV signal, and the digital data stream is recorded in Jiji Lane 俨 HI速率 The rate is recorded in a multi-level way. On a recorded carrier, the method includes the following steps:-read the multi-level code from the record carrier, an oblique ^ ^ ^ ^ stream based on the TV signal, and convert the multi-level code to-digits at a lean rate Data-Add this digital data to a round. On the tape, whether it's the speed of the bit stream or not. Therefore, if a digital TV signal is recorded in the air, or in a pre-recorded tape format with multiple bit numbers, the data rate may be greater than that supported by the playback device.

-VHS video recorder can enable it to play back a digital TV signal with a data rate of 5 million bits / second or more, depending on the level of the multilevel code. The present invention also provides a device for Recorded on a magnetic tape, the band rate of the device 'This device includes a device that receives a digital data stream with a multilevel code smaller than the received digital data, and sets the multilevel. The digital data stream method means that the television signal width is smaller than the data speed of the digital data stream. The device 'encodes the data rate of the received data stream only — the code is recorded on the record carrier. Therefore, the rate is more than providing the code. There will be many streams. A video signal is added to the digital data stream at a speed of π-each n- level of data is as fast as a VHS video recorder. The device can be arranged to record a digital television signal with a large channel bandwidth of the video frequency recorder. The other one is a coder to receive the input data stream and use it with a multi-level level = the data that has been coded during a data period to convert it to a lower rate has been converted. The multi-level code can be compared with the normal analogy This is recorded on the tape. The bit stream device may include a device for adding a received digital bit packet to the coder, where n is greater than 1, and a device converts the bit packet to have at least one bit of each n-bit combined with one bit. And a device for feeding a multi-bit code to the recording head of the recorder at a data speed of 1 / n of the received digital data flow. The encoding device is essentially the same as the device disclosed in the UK patent application No. 96 0 5614, 8 (PHB 3 4056), which was jointly filed by us.] This application uses a multi-level code and a VHS video recorder to record electricity. Biography of the original text. A 4-bit code (n = 2) can double the data rate, while an 8-bit code

^ 01695 Five 'Explanation of the invention (5) Drinking (η = 3) can reduce the data rate by three times. The present invention also provides a device for counting from a magnetic tape to a television signal. The digital data stream is coded at a rate of the data rate of the data stream returned by a plurality of poor streams. The digital multi-level code signal is fed to a decoder. The solution includes: the device is used to convert the data rate of the stream to convert the multi-level code into a binary system. The digital data is fed to a television receiver for display. . The code and a multi-level code provided by a device may be a 4-bit code, and the decoder can generate two bits. Since the mother-a 4-digit standard code, a digital television signal recorded in a "non-air" or pre-recorded magnetic tape using a multi-digit quasi-ma; · a green digital data stream can be played back by a vhs video recorder ' The VHS video recorder is equipped with appropriate de-mapping devices to enable the digital data stream to be read from the multi-level code of the magnetic tape. The re-structured decoder may include an equalizer, which may be a decision-return equalizer. Providing such an equalizer can improve the performance of the decoder, especially in the presence of noise. This option increases the number of levels in the multi-level code, which is more important, and adds a larger performance requirement to the decoder. The invention also provides a VHS video recorder, which includes a selector to select and record analog television signals or digital television signals, and also includes a device for encoding the digital television signals at a data rate lower than the data rate of the received digital television signals. Becomes a multilevel signal, and the device is adapted to record the multilevel signal on a magnetic tape. In this way, a video recorder can be provided to record analog TV broadcasts and digital TV broadcasts without the need to modify the record or because of the playback mechanism.

D: \ Y87 \ 54650.ptd Page 9 4〇ί685 V. Description of the invention (6) Playback magnetic head " Γ Records TV signals and digital video signals without changing the drum speed. As a result, inexpensive mechanisms can be used, and any changes to the VHS recorder are limited to the choice of sources and digital signals for Gamma and decoding that can be implemented with integrated circuits. The recorder may include another coder to encode the analog television signal into a digital television signal. The selection device is arranged to still select the digital television signal = another digital television signal to be added to the coding device mentioned first. Or the decoder may include another selection device to direct the analog video signal played back from a tape to an analog output and to direct a multi-bit signal played back from a tape to a multi-level decoder to convert the multi-level Letter · No. Mo signal. Take w scorn for two daggers: the encoder has a frame, that is, it can be used to record digital and analog TV k numbers, and to play back an analog recorded tape for an analog output, and a recorded tape for a digital rotation. This: The recorder can include another coder to code the analog TV signal, or another digital TV; =-Digital TV signal

The data rate between MPEG l MPEG yuan / second will be-analog TV shirt to 10 million bit TV signals. MPEG 2 coded ° ~ code becomes a digital VHS analog VHS analog video f Data then-high-quality recording is possible and recorded with a level coder 'This video recorder can include ^ multi-level decoder for Read from tape

401695 V. Description of the invention (7) Multi-bit quasi-codes are decoded, and the encoder decodes digital television ^ ^ One video stream,-digital video signal, and device and convert it to-standard analog electric clothes straight Μ for feeding analog TV signals to this point-the recorder can accept 1 TV signal number for recording, and then the left gate # 冰 马 digit k-bit signal is a quasi-type, and then converted from tape playback Number horse standard analog electric signal. Because it is coded according to the MPEG 2 standard, it is conceivable ^ ^ If the television signal is often compared with the H signal, the cost of the original invention on the recorder and other characteristics will be detailed from the following examples. The reference to the accompanying @ formula is more explicit. The ^ method is shown in Figures 1a and 1b, which are standard television teletext broadcast signals and VHS recorder's limited bandwidth. Digital map 2 on this signal is representative broadcasting The low level of the teletext signal is suitable for recording on or playback from a VHS recorder. ΒΛ 尨 Figure 3 is an enlarged time scale of the signal shown in Figure 2 Figure 4 is the device of the present invention Block diagram of the first specific example, knife, FIG. 5 is a block diagram of the second specific example of the device of the present invention, and FIG. 6 is a block diagram of the third specific example of the device of the present invention. Figures la and lb and Figure 2 are side-view signals broadcasted by teletext, and illustrate the codec used in our joint application for υκpatent application no. 960 5664.8 (ΡΗΒ 340 56). Recorded on or played back from a VHS VCR tape. Text la Figure 1 shows a standard broadcast television text message received by the receiver. The data rate of teletext is larger than 5MHz, so page 11 of this No. D: \ Y87 \ 54650. Ptd 401695 V. Description of the invention (8) '-In a standard VHS video recording with a channel band of about 3MHz Distorted. Figure ib shows that the broadcast teletext signal is affected by the frequency bandwidth of the VHS recorder. It can be seen that the original clock operation information has been lost and this signal cannot be decoded by a standard teletext decoder during playback. To overcome this problem, a multilevel code with a data rate that is lower than the standard teletext data rate is used to solve it. _ Figure 2 shows the teletext lines of the four-digit quasi-marga. Initially the clock operation was replaced by a low-frequency clock operation, and the data was replaced by a 4-bit quasi-code. The 4 level in this example is the four-wave amplitude level. 'Therefore, two bits can be coded in the 4-bit car during each data period " T'-I-, and thus the codes 〇〇, 01, 10, and 11. As a result, the current data speed of the text broadcast signal based on multi-level quasi-codes is within the wave bandwidth of the VHS recorder. We understand that the addition code of digital TV signals with up to 5 million bits per second has been performed 'and that these digital TV signals can be recorded and replayed using VHS with appropriate encoding and decoding circuits. This assumes the use of residence. 8-bit or 16-bit or higher will enable higher-bit TV signals to be recorded ', but will add higher performance requirements to the codec decoding circuit. With digital television signals, there may be no clock running on each line and the code 'results' must pass all incoming data through buffer memory and record all on tape. When playing back, he also did a good job in history / Naibu added the clock operation and calibration code to the data read from the tape. This point is Ma 5's recorded digital TV signal

Important difference from recording teletext

D: \ Y87 \ 54650. Ptd page 2 4016 ^ 0 V. Description of the invention (9) —— No. multiplex signal of teaching signal, but it can also multiplex with a digital television signal. Figure 4 shows a block diagram of a VHS video recorder that can record and play back digital and analog TV signals. As shown in FIG. 4, the items included in the dashed box 1 are in addition to or in addition to the standard components of the VHS video recorder. These components enable digital television signals to be recorded. As shown in Figure 1, the recorder has-the air input 2 is close to the normal tuning circuit 3, the intermediate frequency stage 4 and the demodulator 5, and the complex output is a standard CVBS signal. The output of the demodulator 5 is fed to the selector circuit 6 and the input 6 of the circuit 7, and its output is fed to the normal brightness, envelope and audio signal processor 8 of a VHS recorder. The processor 8 has a connection from the recording and playback head 9. A remote handset 1Q is connected to the remote receiver u to allow instructions from the user to be transmitted to the video recorder in a known manner. These user instructions will set the recorder to record a received signal under certain conditions; if it is an analog signal, the channel selected by the tuner 3 will be controlled by the remote handset / telephone 10, if it is a digital signal , The interface of input 5 and output 6 will be operable. In addition, the arrangement of the selector 7 can be selected between the analog input of input 6 or the digital television signal input of input 12. This is controlled by a control and timing circuit 13, which receives instructions from the remote control handset / telephone via the remote control receiver 11. The control and timing circuit 13 controls the recording of digital video signals in addition to its normal control and timing functions in the VHS recorder, which will be described later. The traditional functions of the VHS VCR are outlined only as they are not relevant to the present invention. As shown in Fig. 4, the recorder also includes another input 14 to which the two digital television signals are applied during operation. This digital TV signal may come from a TV set-top box, or from a digital TV receiver, and is controlled by a standard digital interface.

401695 V. Description of the Invention (ίο) As received by IEEE 1394. This digital data stream is fed from the -input interface 15 to the -buffer storage and error correction circuit under the control of the control timing circuit 13. The output of the buffer storage 16 is fed to the tape encoder 17. Coder 丨 A data stream with a data speed of 5 million bits / second will be converted to a multi-level code with a data speed of less than 2.5 million bits / second. This has been shown in my joint patent application. · 96 ° 5614.8 (PHB 3 4056). This coder will produce a multi-bit quasi-code setter with two many bits. Therefore, the low data speed can be achieved to make it: within the bandwidth of the standard VHS VCR, but at the cost of adding and complicating digital data by encoding and decoding. In our example of using the same patent application, 'Using the four volatility levels can make each data period = one bit 7L, so it is one of the required data speeds: = convergence, use a larger number of Amplitude level and / or phase. Bit =: can be coded during each data period. In this case, when the user updates the frequency, the 'selector 7 accepts the input of the input 12 automatically, and "Fig. 4 is a VHS video recorder", which includes a selection device 7 to select an analog or digital television signal. It consists of adding a TV signal to become a cautious button, * you, and lamenting the multi-bit speed of the digital data ㈡ 枓 = the amount of digital TV signals received through the selector 7 to the processor I is magnetic! Coder 17. This multi-level signal is recorded on the magnetic tape from there to the recording head 8 to record the multi-level on the tape for playback. Arrange a different one—selector 18 will turn page 14 D: \ Y87 \ 54650. Ptd 5. Description of the invention (π) This signal will be used to reverse the function of a tape to resolve the evil 1q. The output will be determined. Congratulations decoder 19 Execution and Gamma 17 memory and error corrector 16. The buffer 13 is fed to the buffer under the control of the road ^ * ^ ^ ^ The output of the buffer memory 16 is received in the same manner as in 2f for record preparation, such as playback of a pre-recorded with multiple quasi-magama Magnetic tape, there are standard digital pay ^ ^ ^ ^ digital format can be used to use a TV set-top box or a digital solution circuit to communicate with her, the TV for display. This output is fed from the "" face 20 to the output 21 'where digital TV signals are available. An analog TV signal is played back, set by the selector 18, under control of the control circuit 13' and its input is fed to the The second output 2 and the second output 2 can be connected to the SCART output 23 as a standard CVBS signal, or converted to a UHF signal by a modulator 24 and sent to the air output 25. In terms of analog recording and playback, standard VHS video The only increase in the recorder is the first and first selectors 7 and 18, which route analog signals for recording and playback in response to the user's entry instruction using the remote handset 10 for remote control. When a digital TV signal is to be recorded During playback, when the first and second selectors are arranged, the second input of the first selector 7 can be selected to record this signal, and the first input of the first selector 178 can be selected for playback signals. Receive The digital TV k number is coded by the coder 17 in the same form as in our common patent application and decoded by the decoder 19 during playback. The form is also taken from our common patent application The form of disclosure. We can see that the mechanical functions of the standard VHS video recorder are preserved. The result is that a relatively inexpensive mechanism can be used to record and play back digital television signals and analog signals. For example, if a four-digit code is used such as Our joint patent application

D: \ Y87 \ 54650. Ptd Page 15 V. Description of the invention (12) ---- If it is not revealed, a 5 million bit / second input can be converted into a 25 million bit / second input To record on tape. This will be within the bandwidth of a standard VHS recorder. If you do not use 4 digits, but use 8 digits, the data speed " T thinks that the division between the number of levels and the reduced bandwidth needs to be considered. As stated in my common patent application, and amplitude levels, multilevel codes can include phase changes or even a combination of both. Therefore, with a higher number of coders, higher bit rates can also be recorded, but at the cost of the complexity of the coders and decoders. Fig. 5 is another courtesy example of the video recorder of the present invention, in which the analog and digital television signals received are recorded on the magnetic tape in digital format. Each component in FIG. 5 is assigned the same reference number as the responder in FIG. 4. In the description of FIG. 5, only those different from those in FIG. 4 will be described. The main difference between the arrangements in Figs. 5 and 4 is that after the demodulator 5, a digital video encoder / decoder 30 is included. An integrated circuit that can provide MPEG-2 encoding with less compression than professional equipment and is cheaper has been revealed by the authors Albert van der Werf, Fons Bruls, Richard K1eihorst, Erwin Water lander, Math Verstraelen, Thomas Friedrich The author's article "I.MclC: A single-chip MPEG-2 video encoder for storage" was published in the abstract of technical papers in the 1997 IEEE International Solid-State Circuits Reference. In this way, a high-quality video with a data speed of 5 megabits per second can be provided. Therefore, an analog TV signal can be fed to the digital video coder 30, and its output passes through the selector 70 to the buffer RAM. And the error correction circuit 16 in the same manner as the specific example in FIG. 4. The digital video signal is passed through the selector 7

D: \ Y87 \ 54650. Ptd page 16 5. Description of the invention (13) Over-digital input / output interface 31. This digital input / output interface 31 is a combination of two interfaces 15 and 20 of 4, so when recording, the main difference between the specific examples in FIG. 4 and FIG. 5 is that the analog signal is added to the selector 7 in the adder. 3 0 is converted into a digital signal. The analogy of digital conversion is treated in the same way as one of the digital TV signals added to the turn 14: Analog and digital TV signals are recorded digitally on magnetic tape. The playback of the tape recorded by this method will be processed in the same way as the digital TV signal in FIG. 4 except for the digitization and coding analogy. Signal = Self-buffering RMA and error correction circuit 16 feed to the digital. Bit ^ ° decodes this frequency solution r; i; = SCA: T socket 23 or to modulator 24. The number "3 solution: the device is well known, its form and digital electric two. In order to preserve the recorder's ability to play back the tape recorded by analogy; middle :: 8 can be reserved, under the control of the control circuit 丨 3 ^ ， 22 ， 俾 自 虑 理 || Xi Xi 「17 口 〇 乂 * ^ 5 ^ 1 ^ Select the analogy to turn out 32 m two daggers and send the self-output 22 to the other-the selector b selects the benefit 32 in the time circuit 1 Under the control of 3, the selection is made τ δ or the output of the digital video coder / decoder 30 is selected and the output of the selection option 18 is selected. The selector 7 is one: source u η, which is recorded digitally. , And come from an external source. • During playback, this digit is "coded" and then converted into a standard analog "" ° to resolve to the modulator 24 and the air connection ^ ^ t via SCART endpoint 23 or 31, only 1 & Medium Connection 25 In addition, digital video output is obtained via the input / output interface. All records are now connected in the same format 彳 WT to ^ quasi analogue τν and $ f to external digital video

4〇1695 V. Description of the invention (14) The dema, even when playing back a pre-recorded digital TV tape. The tape recorded in this case cannot be played by the conventional VHS VCR because the recorder 囷 6 shows the modification of the recorder in FIG. At this time, the 'digital video add / drop decoder uses a different encoding algorithm, which requires a lower bit rate, such as MPEG 1 instead of MPEG 2. This may make the image quality slightly lower, but the data capacity of only 1 to 5 megabits per second is enough to encode the TV signal according to the MpEGl standard. In this case, more than one program may be recorded simultaneously within the data capacity of the VHS digital recording system disclosed in this application. Therefore, as shown in FIG. 6, 'there are three tuners 3_1 to 3_3, three IF stages .4-1 to 4-3, and three demodulators, 5-1 to 5-3, each of which feeds a digital Video codec decoder 30. The application of this facility is used when the user wants to record more than two programs transmitted on different channels with the same overlapping transmission time. Thus many programs, such as three, can be recorded simultaneously. During playback, a channel can be selected for playback. This arrangement can be used to extend the capacity of the magnetic tape. It can record programs that are three times longer, or record the programs that are twice as long on the same length of tape. Thus, a reduced-speed channel can be recorded, the magnetic tape is then rolled back to the beginning, and channels 2 and 3 on the tape are repeated. During playback, the digital video decoder 30 contains circuitry to identify individual data streams, and the user selects the desired data stream via the circuit 13 with the handset 10 remotely controlled. The selected data stream is decoded and sent to TV in analog form. Alternatively, the desired data stream is selected and transferred to the digital video output bus. In this method, all data streams can be passed to the digital video output bus. The choice of management materials is performed by external equipment. " 401695 V. Description of the invention (15) After reading the above disclosure of the present invention, other modifications to this artisan are also feasible. The modifications include features known in design and use of video recording devices and components, etc. These components may be substituted or have features other than those mentioned in the above disclosure. Although the scope of the patent application has listed the combination of features, I understand that the scope of the application of the present invention also includes a novel combination of the above features and a summary of one or more of these features, which should be obvious to the skilled person, and It does not matter whether it is related to any one of the scope of patent application or whether it reduces the same technical problems as the present invention. The applicant hereby announces that the scope of a new patent application may be made after such characteristics or a combination thereof, and that other applications are possible during the application of the present invention or derived from the above characteristics.

D: \ Y87 \ 54650.ptd p.19

Claims (1)

401695 Amendment No. 87114194 6. Scope of patent application 1. A method for recording digital signals on a magnetic tape by using a video recorder with a digital data stream, the method includes the following steps;-receiving a digital data stream-using a recording device This data is converted to a multilevel code at a data speed within the bandwidth range, and-the multilevel code is recorded on the tape. 2. The method according to item 1 of the scope of patent application, wherein the multilevel code includes a signal with more than two amplitude levels. 3. The method according to item 1 or 2 of the scope of patent application, in which the multi-level code has four levels and the data speed is half of the data speed of the received digital data stream. 4. The method according to item 1 or 2 of the patent application scope includes the steps of receiving many television signals and multiplexing these many television signals to generate a digital data stream. 5. The method according to item 4 of the scope of patent application, wherein the received television signal is an analog television signal including the step of adding the analog television television signal to a coder, and the coder encodes it into a fixed-format digital Data stream. 6. —A method of playing back a television signal from a record carrier by a playback device using a digital data stream. The bandwidth of the playback device is less than the data speed of the digital data stream. The data speed of the television signal is recorded on a record carrier. This method includes the following steps:-reading the multilevel code from the record carrier,-converting the multilevel code into digital data at the data speed of the television signal O: \ 54 \ 54650.ptc 2000. 03. 07. 020 401695 Case No. 87114194 B Amendment 6. Range of patent applications, and-Add digital data stream to an output. The video signal is recorded at the data speed of a tape stream, and a device will receive the received digital data at a speed less than the speed for recording this multi-level code, wherein the coded digital data stream is added to a coder for The η-bit packet is converted into an η-bit combination, and this is fed at 1 / η times the speed * where η = 2. 1 of which η = 3. The device of item 0, the device of item 0, including a visual signal to a digital coder, each analog TV signal is supplied to an output, and the first plus 7 including a large number of digital coders is added. — A way for digital data stream An electronic device having a digital bandwidth smaller than that of the digital device. The device includes a data stream that receives the digital data stream and receives the data speed of the digital data stream. The data stream is coded into a multilevel code and a device record carrier. . 8. The device flow according to item 7 of the scope of patent application includes a digital resource η-bit packet that the device will receive, where η is greater than 1, and a device has a multi-level code, which has at least one bit. For setting the level code of the data speed of the received digital data stream to the recording head of the recorder. 9. Apparatus according to item 7 of the scope of patent application 1 0. Apparatus according to item 7 of the scope of patent application 1 1. Multi-level code according to the scope of patent application 7, 8, 9 or 1 contains many amplitude levels. 1 2. According to the 7, 8, 9 or 1 multi-tuning circuit of the patent application, each of them is arranged by an analog power. The arrangement of the digital coder can be coded to a corresponding digital television signal and code-up device. A data stream contains a multiplexed data stream analog TV signal. 1 3. — A way to play back TV signals from a tape in a digital data stream O: \ 54 \ 54650.ptc 2000. 03. 07. 021 Amendment _ Case No. 87114194 VI. Patent application range device. This digital data stream is recorded by multi-level code at a data speed that is less than the digital data stream. The device includes a device for feeding a multilevel code signal to a decoder. The decoder converts the multilevel code into a binary code at a data rate of a digital data stream, and a device for feeding the binary code to a television receiver. Machine for display. 14. The device according to item 13 of the scope of patent application, wherein the multi-level code is a 4-bit code, and the decoder generates two bits from each 4-bit code. 15. The device according to item 13 of the scope of patent application, wherein the multi-level code is an 8-bit code, and the decoder generates three bits from each 8-bit code. 16. The device according to item 13, 14 or 15 of the scope of patent application, wherein the data from the decoder is written into a buffer RAM. 17. The device according to item 13, 14 or 15 of the scope of the patent application, wherein the decoder includes an equalizer. 1 8. The device according to item 17 of the scope of patent application, wherein the equalizer is a decision to return equalizer. 19. The device according to item 13, 14 or 15 of the scope of the patent application, wherein the multilevel code includes many amplitude levels. 20. The device according to item 13, 14 or 15 of the scope of patent application includes a multi-level decoder to decode the multi-level code from the magnetic tape and generate a digital television data stream. A digital decoder is provided for The digital television data stream is decoded and converted into a standard analog television signal, and the device feeds the analog television signal to an output. 2 1. — A VHS video recorder including a selection device for selecting to record an analog TV signal or a digital TV signal, and a device for adding a digital TV signal at a data speed that is lower than the data speed of the received digital TV signal O: \ 54 \ 54650.ptc Page β 2000. 03. 07. 022 _ Case No. 87114194 Amended on March g, 57_ Six. The patent application range code becomes a multi-level signal, and a device records multiple bits The exact size is on the tape. 2 2. The VHS recorder according to item 21 of the scope of patent application, including another selection device for directing the analog television signal played back from a magnetic tape to an analog output, and directing the multilevel signal played back from a magnetic tape to a The multi-level decoder converts the multi-level signal into a digital television signal. 2 3. The VHS recorder according to item 21 of the scope of patent application, including another coder for coding an analog TV signal into another digital TV signal. This selection device can be arranged to select a digital TV signal or another digital TV signal. In order to add to the coding device mentioned for the first time. 24. According to one of the items 21 or 23 of the scope of the patent application, the VHS recorder includes a number of tuning circuits. After each tuning circuit is arranged, it can pass an analog TV signal to a digital coder. The digital coder can be arranged after the arrangement. Each analog television signal is coded into a corresponding digital television signal, and an output is provided to be added to the first coding device. A data stream includes a multiplexed data stream, which includes many digital television coded analog television signals. 25. A VHS video recorder according to one of item 23 of the scope of patent application, including a multi-level decoder to decode the multi-level code from the magnetic tape, and generating a digital television data stream, a digital decoder for The digital television data stream is decoded and converted into a standard analog television signal, and a device is provided for feeding the analog television signal to an output. O: \ 54 \ 54650.ptc Cap 2000.03.07.023