JPH05506968A - 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 invention starts from a video recorder according to the preamble of claim 1. this Video recorders of this format have audio signals of high quality (high-grade) in the HiFi category. as ffHiFt-VH3 or HiFi-3-VH8 It is publicly known. This type of video recorder has a recording frequency of approximately 5 to 5.6 MHz. recording of audio signals in HiFi quality and increased bandwidth of brightness signals have. On the other hand, the chrominance signal is a frequency spectrum of the video carrier wave modulated by the luminance signal. At the bottom of the spectrum, there is a frequency-converted signal, also called the “color under” Recorded by color subcarrier. This type of recording uses a color signal of about 0.5 MHz. bandwidth. Therefore, color reproduction depends on sharpness and S The N ratio is relatively unsatisfactory.

When recording a high quality (high grade) 2-MA C signal, this signal is It must be decoded, re-encoded in PAL and recorded in the manner described above. subordinate Similarly, in this format of recording, the quality characteristics of the D2-MAC signal are partially restored. Lost. Here too, the RGB signals that are ultimately required for image reproduction Simultaneous wide-bandwidth recording of However, this format of record is in the format described above. This is not immediately possible with other video recorders.

An object of the present invention is to provide a video recorder with sufficient bandwidth for optimal reproduction of RGB signals. The goal is to configure the device so that recording can be performed simultaneously over a wide range.

The present invention is based on the following considerations. A diagonal track with a track width of approximately 50 μm. It is noted that dividing the track into two tracks with a track width of 1/2 of about 25 μm This is possible in terms of recording quality and the feasibility of corresponding heads. 1/2 track width This type of recording has a long running time, the so-called "long play" This is already done in recorders using separate heads. Therefore, the present invention This method then tracks along the conventional track having a width of about 50 μm. By halving the width, two heads can be used to generate two mutually independent signals over the full bandwidth. Used to record width. At that time, approximately 3MHz is required to record the B signal. The fact that relatively little bandwidth is sufficient is exploited. This means that the color reproduction This bandwidth alone is sufficient for the B signal when forming Y from RGB. is based on the fact that only 10% are involved anyway. that Therefore, the missing frequency region of the B signal of approximately 3 to 5 MHz is can be substituted (replaced) with corresponding components of RGC signals without loss of quality. I can do it.

With the solution of the invention, for example, D2-MA C-signals can be recorded in perfect quality. and therefore the special quality characteristics of this signal during recording are not lost. You can do whatever you like. Recorder without complicated decoding and matrix circuits RGB signals can be sent directly to the output side, and RGB provides high quality image reproduction. advantageously used for. The solution of the invention does not increase tape consumption and does not shorten the recording duration of a given tape. By recording RGB signals, There is no need to record orthogonally modulated color subcarriers (color under). So Therefore for this purpose it is set below the frequency range of the modulated video carrier. The frequency range is the frequency modulated audio carrier for the so-called HiFt-sound. It can be used against. Optionally, the frequency domain of the modulated video carrier is , can be extended to lower frequencies, i.e. into the color under region; This further increases the bandwidth of the recorded Y signal.

Next, the present invention will be explained in detail with reference to the drawings with reference to the illustrated embodiments.

FIG. 1 is a diagram showing a frequency spectrum for detailed explanation of the present invention, Figure 2 is a block circuit diagram for recording, and Figure 3 is a block circuit diagram for reproduction. FIG. 4 shows the frequency spectra of baseband signals R, G, B. It is a line diagram.

As shown in Figure 1, the R signal has a frequency deviation of 54 to 7 MHz. By frequency modulating the image carrier wave to The information is recorded on the surface layer S1 of the magnetic tape T with a small gap width. Head Kla is halved by 24.5 μm compared to a conventional head with a track width of 49 μm. It has a track width B/2. Below the frequency spectrum of the video carrier, the frequency The frequency modulated audio carrier wave T1 is recorded at a frequency of 0.8 MHz ± 200 kHz. will be recorded. Therefore, a track having a width of B/2 recorded in a conventional recorder Half of the space is vacant when recording the signal R. C signal has track width B/2 Similarly, using the head Klb, but with the R signal, the empty track width B/2 recorded in Down the frequency spectrum of the video carrier modulated by G, Audio signals are recorded with a frequency of 0.4 MHz±200 kHz. T1 is T2 contains the right channel audio signal of the teleo signal, and T2 contains the left channel audio signal. Contains the number. The frequency difference between T1 and T2 is due to the frequency selective nature of these audio signals. This is to enable separation and achieve high crosstalk attenuation.

According to Figure C of East 1, it has a relatively large gap width of 0.4 to 0.45 μm. 2 is provided on another magnetic head. These heads have relatively large gaps Recording is performed in the deep layer S2 of the magnetic tape T depending on the width. B signal by 2 to head The signal also has a static frequency deviation of 35 to 4.5 MHz and approximately 1.5 MHz. By frequency modulation of the video carrier, which occupies the frequency range of 2 to 4.5 MHz, recorded. At this time, the recording bandwidth of No. BM is approximately 2.65 MHz. To K2 When only the B signal is recorded, the track width of B/2 is 2 and 1/2 on the head. There is no need to split it into two heads. However, as with 2 in the head and 1 in the head, 1 It can be divided into two heads with a track width of /2. In that case, in deep S2 , additive to the B signal in the frequency range from 1.2 MHz to 4.5 MHz. for example two frequency modulated audio carriers and/or a DQPSK modulated Another signal in the form of an audio-PCM-signal can be recorded. R1G The signal is recorded with a bandwidth of approximately 5.6 MHz and the B signal is recorded with a bandwidth of 2.65 MHz. Recorded by bandwidth.

In the recording circuit shown in Figure 2, the R signal is cut off at 5.6 MHz together with the synchronizing signal S. Low pass filter with frequency 1. Sub-pre-emphasis stage 2. amplitude limiter 3, 1/2 of the track width B/2 through the FM modulator 4 and the recording amplifier 5, respectively. The two heads with reach 1a. The two heads Kla are +6° and -6 It has an opposite azimuth angle of °. The signal G+S corresponds perfectly to R+S The head Klb is reached via the paths 1a, 2a, 3a, 4a, and 5a. head K lb is spatially located on the head drum relative to the head Kla, so that they are in Fig. 1B. As shown, to.

Another track with a track width B/2 on which the signal R was not recorded by the track Kla. Arranged to record racks. The signal B+S is 2. 8MHz cutoff a low-pass filter 6 with a frequency, a pre-emphasis stage 7, an amplitude limiter 8. FM strange The signal reaches the head 2a via a regulator 9 and an amplifier 10. These heads are As shown in Figure 1C, the signal B+S is magnetically placed at 1/2 track width B/2. The information is recorded in the deep layer S2 of the air tape.

The audio signal NFI is supplied by a disturbance suppression circuit 11. in the form of a Dolby or high cam circuit. amplitude Restrictor 13. Through the FM modulator 14 and the low-pass filter 15, the audio carrier T1 The summation stage 16 is reached in the form of . The second audio signal NF2 is transmitted via a corresponding path to the audio signal NF2. It reaches the adder stage 16 as carrier wave T2. From the output side of the addition stage 16, the sum T1+72 is It reaches the heads 2b via an amplifier 17, and by these heads the sound carrier Tl , T2 are recorded on a track width B/2 where B is not recorded.

Therefore, in FIG. 2, the recording of the audio carrier waves TI, T2 is as shown in FIG. 1a, b. 1C, but according to the variant according to FIG. 1C. 2a on the head 2b and 2b are recorded in an intermediate region of approximately 2.5 μm between tracks, the so-called This is done with a track width of approximately B/2-22 μm with grass. On this lawn Therefore, the signals in two adjacently located tracks each having B/2 Crosstalk between is avoided. Tracks located adjacent to each other with 1/2 track width 2a on the two heads relative to the rack have an azimuth angle of +30″ and -30° have.

In the reproducing circuit of FIG. 3, the signal of FIG. 1a is transmitted from the head Kla to the head switch. 18. Delay time stage 19° amplitude limiter 20. FM demodulator 21.6MHz cutoff frequency as a signal R via a low-pass filter 22 and a de-emphasis stage 23 having a It reaches terminal 24. Same routes 18a, 19a, 20a, 21a, 22a, 23 A G signal is taken out at the terminal 24a via the terminal 24a.

As shown in FIG. 1, the head 2a has a head switch 25. delay time stage 26. Amplitude limiter 27° FM demodulator 28. Low frequency with cut-off frequency of 2.7 MHz The B signal is sent again to the terminal 31 via the band pass filter 29 and the de-emphasis stage 30. put out Therefore, RGB signals are taken out simultaneously to terminals 24, 24a and 31. . The B signal is a spatially shifted audio carrier wave T recorded using 2b in the head. 1 is a head switching device with a pass range of 33.1.4 MHz ± 200 kHz. Filter 33. Amplitude limiter 34. FM demodulator 35° de-emphasis stage 36 and It reaches the terminal 38 via the fault suppression circuit 37, where the audio signal NFI is taken out. . Reached via the same paths 33a, 34a, 35a, 36a, 37a, 38a Then, the audio signal NF2 is extracted.

In Figure 3, the RG multiplied signal has a full bandwidth of approximately 5.5 MHz, while the B signal is about 2. It has a reduced bandwidth of 8MHz. For color channels, analogy For example, in order to extract the modulated color subcarrier from RGB, a comparison of 2.8MHz is required. Since only a small amount of bandwidth is required, the bandwidth of the B signal is relatively small. is not important. However, when forming the Y signal from RGB, signal B itself is necessary. Therefore, it does not have the required bandwidth.

FIG. 4 shows the frequency spectra of baseband signals R, G, and H.

R and G have a full bandwidth of approximately 5.6 MHz. B is 2.8MH It has only a small bandwidth of z. Missing in B, 2. 8MHz The frequency range from 5.6 MHz to 5.6 MHz is determined by corresponding signal components from R and G. For example, it can be determined from the average values of R and G. This means that (a+b)/2 Therefore, it is shown. That is, when reproducing a wideband Y signal, the reduced bandwidth of B This does not cause any significant inconvenience. This is because B is the following formula Y=0.59G+0.3R〇, only 11% is involved in Y according to IIB That's because there aren't any.

As shown in FIGS. 1a and 1b, a track having a conventional width B is Divide into three tracks each having a width of B/3 and each having a width of B/3. Simultaneously transmit three color signals to these three equivalent parallel tracks at 5.6MHz. It can also be recorded with full bandwidth.

Summary book In the VH8 or 5-VHS video recorder, the color signal is recorded using the so-called "color signal". “Under” the video carrier is carried out only by a small bandwidth of about Q, 5 MHz. It will be done. An object of the present invention is to enable high-quality simultaneous recording of RGB signals. . Each video head (K1. to 2) has a track width of 1/2 (B/2). are replaced by two heads, and the RGB signals are transferred to the magnetic tape by these heads. recorded in the superficial layer (St) and deep layer (S2) of the loop (T). In particular, D2-MA Used for 5-VHS video recorders for high quality recording of C signals.

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Claims (8)

[Claims] 1. Video in which the video carrier modulated by the image signal has a relatively small gap width Recorded by the head (K1) on the surface layer (S1) of the magnetic layer tape (T) and another The signal is sent to the deep layer (S2) by the second magnetic head (K2) with a relatively large gap width. ) is a color record recorded in tracks parallel to the tracks of the magnetic tape. In the improved video recorder, each one head (K1, K2) is , replaced by two heads (K1a, b; K2a, b) with 1/2 track width (replacement) and the RGB signals are recorded simultaneously by both heads. A video recorder with improved color recording, characterized by: 2. The R signal and the G signal are transmitted to the first head (K 1a, b) on the surface layer (S1) and the B signal is recorded on the surface layer (S1) by the second head (K2 The recorder according to claim 1, wherein the recorder records in the deep layer (S2) by a, b). 3. During reproduction, when forming a luminance signal (Y) from RGB signals, in the B signal The missing upper frequency region is replaced by the corresponding component from the RG signal. The recorder according to claim 1. 4. Two mutually complementary heads with 1/2 track width each form a combination. 2. A recorder according to claim 1, wherein the recorder is formed by a swivel head. 5. The two heads (K1a, b; K2a, b) perform recording in the track direction. claims that are geometrically offset from each other by the length of two television scan lines The recorder described in item 1. 6. The two heads (K1a, K1b) have opposite azimuth angles. 2. The recorder according to claim 1. 7. The image modulated on the surface layer (S1) by the first head (K1a, K1b) In the frequency region below the carrier wave, low frequency audio signals (NF1, NF2) 2. The record according to claim 1, wherein frequency-modulated audio carrier waves (T1, T2) are recorded. -da. 8. As a head (K1a, b; K2a, b) with a track width of 1/2 (B/2) , a head provided for long-term operation with 1/2 tape longitudinal speed is utilized. 2. The recorder according to claim 1, wherein the recorder is used as a recorder.