JPH05506130A - Video recorder with improved color recording - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Video recorder with improved color recording The present invention provides a video recorder with improved color recording. Regarding de-recorder.

In the D2-MA C-system, each time sequentially in one scanning line A time-compressed color difference signal and a similarly time-compressed luminance signal are transmitted; The two color difference signals are transmitted line-sequentially in this form.

In this solution the luminance signal and the chrominance signal or the two chrominance signals are never at the same time. not exist. This avoids crosstalk of these signals. any point in time Since only one signal is transmitted in The entire transmission bandwidth can be utilized. Therefore, this type of signal transmission Significant losstalk and wide bandwidth occur.

Recording of this type of signal using a customary VH3 or 5-VHS video recorder In this case, the signal obtained by the D2-MA C-decoder is converted into FBAS (composite color signal shall be newly coded and recorded in the customary manner. This de Coding and new coding to reduce crosstalk and bandwidth Regarding this, the quality characteristics of the MAC signal will be partially compromised again.

The problem of the present invention is to partially reproduce the quality characteristics of the D2-MA C-signal by recording. video recording to allow advanced recording of these signals without loss of signal. It is to compose da.

This problem is solved by the invention according to claim 1. Advantageous implementation of the invention Examples are given in the other claims.

The present invention is based on the following considerations. In other words, the records in the deep layer below are Only a reduced bandwidth is possible due to the relatively large head gap width.

Recording of a video signal modulated by a luminance signal is not possible with this method. deer The chrominance signal typically has a relatively small bandwidth compared to the luminance signal. Therefore The lower depth recording with reduced bandwidth advantageously improves color signal recording. It can be used for recording purposes. D2-MA C color difference signal is located at the bottom. Record at almost the full bandwidth corresponding to the standard of approximately 2.8MHz in the deep layer be able to. thus adding a reduced bandwidth signal to the lower magnetic layer According to the record of the present invention utilized for the purpose of the present invention, what can be recorded in terms of A number of advantages arise, including: Color signals are no longer frequency multiplexed on the surface layer. There is no need to record it together with the luminance signal. This causes the otherwise color subcarrier The frequency spectrum of the video carrier wave is extended to the region below IMHz, which is occupied by By increasing the length, the recording bandwidth for the luminance signal can be widened. This way A bandwidth of 5.6 MHz is thus achieved for the luminance signal. on the other hand Color signals with wide bandwidth can also be recorded. itself is useful for color signals. The second layer used acts analogously to a separate recording medium or separate tracks. . By recording the luminance and chrominance signals in separate layers, the noise between these signals is reduced. Lost talk becomes so slight that it becomes almost unnoticeable. Recording is done using a conventional recorder. compatible. The reason for this is that the lower frequency spectrum of the luminance signal Previous records of color signals using range-converted color subcarriers can be maintained. This is because that. When recording MAC signals, this problem regarding crosstalk and bandwidth Signal quality benefits are maintained. In the MAC signal, the two color difference signals are line sequentially Therefore, sequential recording does not have any disadvantageous effects.

The following embodiments of the present invention will be explained with reference to the drawings.

FIG. 1 is a diagram showing a frequency spectrum in the case of a first type of recording; FIG. 2 is a diagram showing the frequency spectrum for the second type of recording; Figure 3 is a block circuit diagram for recording, and Figure 4 is a block circuit diagram for playback. It is.

The symbols used in the drawings have the following meanings and values:

fH = Scanning line frequency 15.625kHzf 1 = PAL color subcarrier frequency 4 ．． 4336185MHz f2=0.62695313MHz Fm frequency f3=fl+4fh+1/8 fH=5.0605718MHz Mixed frequency f6=2.203125MHz　Mixing frequency for Tl f7=2.40625MHz　Mixing frequency for T2 Frequency modulated audio carrier for L with TI = 1.4MHz ± 150kHz Transmission Frequency modulated audio carrier for R with T2 = 1.8MHz ± 150kHz Transmission Recorded for L in the first field with T3=1.00625MHz R in the first field with a voice carrier T4 = 0.60625 MHz A second phi with recorded audio carrier T5=0.803125MHz for Recorded voice carrier T6 for L in field = 0.4203125MH Recorded audio carrier Fm for R in second field with z = video Frequency downtransformed color subcarrier recorded below the frequency spectrum of the carrier wave Wave (color under) Ft=color subcarrier recorded in lower deep layer f2=f3-fl=40fH+1/ 8fH Figure 1a has a static frequency shift of 5.4 to 7.0 MHz. The frequency spectrum of the video carrier B modulated by the luminance signal Y is shown. There is.

It extends to 1.2-12-1O. Below this frequency spectrum , there is a modified, frequency-downconverted color subcarrier Fm. In this case The generated signal is applied to a magnetic head with a small gap width of about 0.2 μm by 1. is recorded on the surface layer s1 of the air tape T.

In Figure 1, a color difference signal with a frequency deviation of 3.5-4.2 MHz is used. A composite signal consisting of a modulated color subcarrier Ft is shown. Bandwidth of this signal extends from about 1.8 to 4.5 MHz.

The chrominance subcarrier Ft is linearly changed in frequency by the two chrominance signals B-Y and R-Y. It is modulated. At frequencies 1.4MHz and 1.8MHz, the audio signal Therefore, two frequency-modulated audio carrier waves Tl and T2 are present. Figure 1 The composite signal shown in FIG. The information is recorded in the deep layer S2 of the magnetic tape T by a magnetic head having a magnetic head 2. actually First, the recording shown in FIG. 1 is performed using the head 2. After that, the head The recording shown in FIG. The recorded records will be erased again.

That is, the signals shown in FIG. 1a and FIG. The meter is significantly damped and the two layers S1. It is recorded in S2. Two magnetic heads 2 has an azimuth angle of ±36°.

Since the color difference signal is recorded in the layer S2 by the color subcarrier Ft, the color subcarrier Ft m can also be omitted in layer S1. In that case, the frequency occupied by video carrier wave B The number region extends to frequencies as low as about 0.1 MHz, as shown by the dashed line 1. can do. When both Ft and Fm are recorded, on playback, Ft If there is a failure in the color channel, Fm is demodulated and the color channel is used as an alternative signal. can be supplied to In this type of recording using Ft, the recorded color difference signal The signal has a bandwidth of approximately 2.15MHz, which means that the D2-MAC ~ transmitter It enables perfect color reproduction corresponding to approximately 77% of the standard bandwidth. Y also has color difference Both signals are recorded on separate layers 31 and 32, each with approximately full bandwidth. (Y bandwidth is approximately 5°0 instead of 5.5MHz, 89% of MHz).

Another embodiment of recording is shown in FIG. Layer S1 has a different structure compared to FIG. 1a. The shaped video carrier B is recorded. Color subcarrier Fm is omitted. in addition Instead, four audio carriers T3. T4. T5. T6 is recorded as follows. Immediately Two audio carriers each time during a certain field or VH5 diagonal track T5. T6 is recorded and the audio carrier is transferred to the next field or next diagonal track. Sending aT4. T3 is recorded. The frequencies of the two audio carriers are different for each field. Each diagonal track is switched between different values. This is for the following purpose have. between adjacent tracks, acting on the azimuth angle of the head itself. Since crosstalk attenuation is negligible at frequencies below IMHz, Unacceptable crosstalk between audio carriers of adjacent tracks may occur. Ru. Therefore, the frequency of the two audio frequencies recorded for stereo channels R and L is The wave number is switched for each field or for each track. For details on switching this format, is described in West German Patent Publication No. 3306978. For the above reasons, Recording of audio frequencies in layer S2 of 2 is no longer necessary. As shown in Figure 2 As shown, the frequency region occupied by the color subcarrier Ft is affected by the static rIR shift. If it is the same as shown in Figure 1, it is possible to extend it further downward to about I MHz. can. This format of recording typically achieves a bandwidth of 2.8 MHz for chromatic interference. can do.

According to one embodiment, the luminance signal Y is as shown in FIG. 1a or FIG. 2a. is recorded without a sync signal. In that case pure BA (video and blanking) signal can account for the total modulation shift. This results in an effective deviation of only about 30%. This increases the signal-to-noise ratio. Instead, the synchronization signal is a color difference signal. It is recorded along with the color subcarrier Ft along with R-Y and B-Y. According to another embodiment , the amplitude of the color difference signal during recording is always 3.5-4.2MH, regardless of the amplitude. Adjustments are made so that the complete FM modulation shift of z is utilized. At this time, the amplitude of the color difference signal is The width is typically enhanced and subjected to distortion. Additionally, to direct this amplitude increase, e.g. For example, an identification signal in the form of a burst is transmitted at the beginning of a scanning line. This identification message is used during playback. signal, the significantly larger amplitude in the small color difference signal is again the original, correct reduced to value. This format to improve the utilization of transmission capacity in case of small signals The means for this are described in detail in West German Patent Application Publication No. 3333071. Ru.

FIG. 3 shows the recording circuit for the two embodiments of FIGS. 1 and 2. Ru. First, the recording shown in FIG. 1 will be explained. This type of recording requires two toggle switches. Chis 2 and 3 are located at the positions indicated by solid lines. The FBAS signal is a luminance signal in separator 4. signal Y and a modulated color subcarrier F. Y is for sub-defense Step 5. Main de-enhancement stage 6. Via amplitude limiter 7 and FM modulator 8 A linear summing stage 9 is reached. The color subcarrier F is 4.43+0.6-0.8MHz A converter 11 is reached via a bandpass filter 10 with a pass region. synchronous minute In step 12 the scan line synchronization pulse with frequency fH is separated and transferred to converter 1 3, it is converted to the mixed frequency f3 and passed through the bypass filter 14 to the converter. 11 other inputs are reached. On the output side of the converter 11, the frequency low-band converted color is output. A subcarrier Fm appears, which is added via a low-pass filter 15 and a switch 3. Reach stage 9. The output signal of this summing stage 9, shown in FIG. ．． 1 to two heads with a slight gap width of 0.2 μm through 17 Ru.

The color difference signals R-Y and B-Y are low-pass filters with a cutoff frequency of approximately 2.15 MHz. Clamping and, if necessary, simultaneous/sequential conversion of the color difference signals via filter 18 Step 19 is reached. On the output side of this stage 19, color difference signals R-Y, B are applied line-sequentially. -Y appears. These are stage 20. Amplitude limiter 21. FM modulation 0.4 to 0.45μ as the color subcarrier Ft through the amplifier 22 and the amplifier 23. 2 to the head with a relatively large gap width of m. In this case the audio carrier TI, T2 can be recorded as shown in FIG.

In the second type of recording shown in FIG. 2, switch 2.3 is in the dashed position. Shining The frequency signal Y is passed through a low-pass filter 24 having a cutoff frequency of 5.0 MHz. 1 and processed in the same manner as in FIG. Here the color channel path 10. 11.15.3 are not provided with color subcarriers. The lower input side of addition stage 9 is a switch. It is grounded via switch 3. Here, the color recording is performed on the path 19- This is done only via 2 to the head via 23. This place is empty now, 0 - 4 FM sound carriers by 1 in the head in the frequency range of I MHz Wave T3. T4. T5. T6 is recorded in the manner described above. For this purpose, two audio carriers are Transmission wave T1. T2 is the audio carrier T3-T6 from 1.4MHz and 1.8MHz The signal is supplied to a converter 25 which performs the above-mentioned conversion to . The audio transport obtained in this way The transmitted waves T3-T6 are added to amplifiers 16.27 through bandpass filters 26.27. Reach 17. The sound carriers T3 and T4 then enter the amplifier 16 and thus the upper 1 and the sound carriers T5 and T6 are fed to the amplifier 17 and thus to the Only one side head is supplied. This recording of the audio carrier indicates that the color subcarrier Fm is Possible only when not recorded.

FIG. 4 shows a corresponding regeneration circuit. Image transport scanned from tape T Wave B is transmitted to the two heads by a changeover switch 28 that can be switched between 1 and 1 for each track, and a delay switch. a stage 29 used for delay time compensation, an FM demodulator 31 via an amplitude limiter 30; reach. The FM demodulator sends the demodulated luminance signal Y to a low-pass gluter 32 . Deenfu It reaches a terminal 35 via an assist stage 33 and a delay time element 34, where the video is played back. It is possible to take out the Y for. Color subcarrier Fm is converted via a low-pass filter 36 It reaches vessel 37. The luminance signal Y reaches the synchronous pulse separation stage 38 from the terminal 35, and the frequency A scan line synchronization pulse with several fH is applied to the converter 39. The mixed carrier wave f3 is - via a bus filter 40 to another input of the converter 37, the output of which A color subcarrier appears with frequency f1. The color subcarrier is a band pulse filter 41 , a delay time stage 42 and a terminal 44 via a position 43 shown in solid lines.

An FBAS signal is additionally generated from Y and F in stage 45.

The color subcarrier Ft is transmitted from the deep layer S2 at the bottom of the magnetic tape T by 2 to the head. A selector switch 60 for switching between the two modes. Used for delay time compensation. delay time stage 46. It reaches the FM demodulator 48 via the amplitude limiter 47. F The M demodulator is connected to the circuit 5 via a low-pass filter 49 and a de-emphasis stage 50. Two consecutive color difference signals R-Y, B-Y reaching 1 are generated. Circuit 51 It includes a scanning line delay line and a matrix, and reproduces continuous color difference signals. and simultaneous RGB signals, and synchronous and simultaneous color difference signals. for this purpose Stage 51 is additionally supplied with luminance signal Y from terminal 35 .

In the case of the recording shown in FIG. 2 without the color subcarrier Fm, switch 43 is switched to the position shown by the broken line. It is being In that case the color subcarrier F and FBAS signals at terminal 44 are present. I haven't. A complete signal for playback is still present, i.e. at terminal 35. Y at and the output signal of stage 51. This type of record is shown in Figure 2a. The audio carrier waves T3-T6 are recorded. This audio carrier wave is about 1. It reaches the converter 53 via a low-pass filter 52 with a cut-off frequency of 1 MHz. Ru. This converter is supplied with mixed frequencies f6 and f7 from the converter 54, and its output On the side there are again two audio carriers T1. with 1.4 and 1.8 MHz. T2 is now It will be done. These audio carrier waves are passed through a bandpass filter 55 to an FM demodulator 56. , which again has two audio signals NFI and NF2 for L and R. Occur.

Fl(E,I Fig.2 Summary book For example, in new television transmission systems such as D2-MAC, bandwidth and Enhanced a quality with respect to crosstalk and crosstalk is achieved. This kind of signal is usually This signal quality is partially compromised again when recorded by a video recorder. Ru. The problem of the present invention is to improve the quality of the signal by recording the advanced recording of this type of signal. the video so that the parameters can be done partially again without being compromised. The first step is to configure the recorder. Color difference signals (R-Y, B-Y) are transported line-sequentially The second magnetic head (K 2), the information is recorded in the deep layer (S2) located at the bottom of the magnetic tape (T).

Especially used for 5-VHS video recorders for D2-MA C signals. It will be done.

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Claims (14)

[Claims] 1. The video carrier wave (B) modulated by the luminance signal (Y) has a small gap width. Recorded on the surface layer (S1) of the magnetic tape (T) by the first magnetic head (K1). In a video recorder with improved color recording, The color difference signals (R-Y, B-Y) are compared line-sequentially by FM modulation of the carrier wave (Ft). The magnetic tape (T) is recorded in the deep layer (S2) that exists below the A video recorder characterized by: 2. The video carrier (B) is displayed when recording of the color subcarrier (Fm) is abandoned. Broadband modulated to occupy the entire available bandwidth of the surface layer (S1) The video recorder according to claim 1. 3. The color subcarrier (Ft) uses the deep layer (S2) where it resides relatively lower. Claim 1 Recorded bits are broadband modulated so as to occupy the entire possible recording bandwidth. de recorder. 4. The audio carrier wave (T) frequency modulated by the audio signal is transmitted through the upper wide magnetic layer. (S1), recorded below the frequency spectrum of the video carrier (B). The video recorder according to claim 3. 5. Is the frequency of the audio carrier (T) switched between different values for each field? in each case two frequencies are assigned to a given head of a pair of heads, That is, the heads of one head pair are supplied with different FM audio signals. The video recorder according to claim 4. 6. Additional modulated sound carriers (T1, T2) in the lower deep layer (S2) ) is frequency-multiplexed and recorded. The video recorder according to claim 1. 7. During reproduction, a circuit (51) having a scanning line delay circuit and a matrix is provided. The circuit combines continuous color subcarriers (Ft) into simultaneous RGB signals and/or or convert to FBAS signal The video recorder according to claim 1. 8. In the upper surface magnetic layer (S1), only the BA signal without the synchronization signal is recorded. The synchronization signal is additionally recorded in the deep magnetic layer (S2) together with the color difference signal. The video recorder according to item 1. 9. During recording, the amplitude of the color difference signal (R-Y, B-Y) depends on the frequency of the color subcarrier (Ft). tuning so that the wavenumber shift region (3.5-4.2MHz) is always fully utilized. arranged The video recorder according to claim 1. 10. A pilot signal indicating the amplitude change is recorded and the pilot signal is replayed. Claim 9 which acts to reduce the amplitude of the demodulated color difference signal to its original value during raw processing. Video recorder listed. 11. The upper surface magnetic layer (S1) contains the frequency spectrum of the modulated image carrier wave (B). Below the vector, the transformed 2. Video recorder according to claim 1, wherein a color subcarrier (Fm) is recorded (FIG. 1). 12. During playback, interference occurs in the color subcarrier (Ft) from the lower deep layer (S1). In some cases, a modified color subcarrier (Fm) from the surface layer (S1) is used as an alternative signal. used for video playback. The video recorder according to claim 11. 13. An identification signal instructing recording of the color subcarrier (Ft) of the lower deep layer (S2) is The discrimination signal is automatically transmitted to the second head (K2) of the color channel during playback. Performs dynamic switching action The video recorder according to claim 1. 14. The identification signal is formed by additional modulation of the recorded sound carrier (T). is being The video recorder according to claim 13.