The Video-Hi8-recorder can also be used to make audio recordings digital stereo only. Using a 90 minute cassette, one can record 6 x 90 minutes, making a total of 18 hours of continuous music. The video Hi8-system also allows manipulating digital images, such as picture-in-picture and editing.
Video Hi8 uses a combination of the M- and U-tape guidance system. In case of a mono video recorder, the audio signal which corresponds with the image is transferred to a separate, fixed audio head.
As in an audio cassette deck, this head writes an audio track in longitudinal direction of the tape. This is called linear or longitudinal track recording. The video recorder has two erase heads. One is a wide erase head covering the whole tape width which automatically erases all existing image, synchronization and sound information when a new recording is made.
The other erase head is smaller and positioned at the position of the audio track. With this erase head, the soundtrack can be erased separately, without affecting the video information. In this way, separate audio can be added to a video recording. This is called audio dubbing, and can be particularly useful when making your own camera recordings. The linear audio track does have some restrictions. Due to its low tape speed, it is not suitable for hi-fi recordings.
Moreover, the audio track is so narrow 0. The frequency range is limited as is the dynamic range which relates to the amount of decibels , and the signal-to-noise ratio is not very high. The signal-to-noise ratio relates to amount of noise compared to the total signal.
The higher this ratio, the less noise and the better the signal will be. The sound quality of the mono track can be improved by a noise reduction system. There is a way to get superior hi-fi stereo sound quality on a videotape used in hi-fi video recorders, which will be discussed later.
Hi-fi video recorders were developed for improved sound quality. The most common quality of video images is HQ. Conventional mono video recorders use linear audio registration, which does not allow hi-fi recordings. A special method was therefore devised to record stereo sound with hi-fi quality.
In the case of hi-fi, the audio signal is also put on tape via revolving heads similar to the video signal, not on the linear track. As there is no space between the video tracks, as the video tracks lie right next to each other with no space in between, the audio tracks need to be recorded in the same place as the video tracks.
The way this is realized is by recording the audio signal under deeper than the video signal. Hi-fi video recording, where the audio signal is recorded at a deeper level, after which the video signal is recorded on top. In hi-fi video recorders, the audio signal is modulated to a high carrier frequency.
This is realized via FM modulation, with the right channel stereo signal at a slightly higher frequency than the left channel. The corresponding video and audio signals are written to tape immediately after each other. First the FM audio signal is registered at a deep level in the tape's magnetic coating. Straight after the audio signal, the video signal is recorded. As the frequency of the video signal is higher than the audio signal, it will not register as deep in the tape coating as the audio signal.
The video signal erases the audio signal in the top layer and records the video signal instead. Thus, the audio and video signal tracks are written in the same magnetic layer, separately, one on top of the other.
The entire magnetic coating is only 0. To ensure that the two do not interfere, the audio and video tracks are written on tape from a different angle, by means of a different head with a different azimuth setting. So, a hi-fi video recorder always has two audio registration systems installed.
This offers possibilities for amateur video makers to do audio dubbing using an audio mixer to combine the sound of the hi-fi track with other sounds and to write the mix to the linear audio track. In this way synchronized recordings will be left intact. A hi-fi video recorder is also suitable as a high-quality audio recorder, not only because of the professional recording quality, but also because of the long play possibilities and the low recording costs.
The specifications of hi-fi video sound registration systems equal those of professional tape decks and compact discs. The entire sound spectrum can be covered without any problems, and the dynamic range is 80 dB, close to the 90 dB that compact discs can cover. As the video recorder is a recording medium, a couple of good microphones can actually cover the whole 80 dB range. Recordings made on a hi-fi video recorder result in almost unmeasurable wow and flutter and very little harmonic distortion.
The low tone quality of a hi-fi video recorder is remarkably good compared to tape recordings of cassette decks. A disadvantage is that sound editing is not possible via a VCR.
Instead, the required tape segments can be copied unto another tape without hardly any loss of sound quality. A hi-fi-video recorder needs to be tuned very accurately. As the two rotating audio heads function alternately, the recorded sound consists of successive particles and need to fit together perfectly. If they do not, the result is rumble, which is a humming sound. In high quality, well-tuned hi-fi video recorders you will not hear this sound.
It is a recording-playback system of such high quality that its recordings are equal to the quality of direct TV broadcast signals. S-VHS offers better image quality than normal VHS, fuller colors, more sharpness, clearer color separations and color fields, and eliminate moire effects.
As in all video recording systems, recording image and sound on magnetic tape involves the actual image, the colors, the horizontal and vertical synchronization pulses for perfect image building, and finally the sound. The original 7 MHz are reduced to 5 and 3.
The Y and C signals are put separately on tape and separately transferred to the TV when played back. Signal Separation However perfectly the helical scan system works, normal VHS video recorders cannot register the entire 5 MHz range that comes through via a television broadcast. The bandwidth is reduced to 3. Taking away almost 2 MHz is not a matter of simply filtering the signal, as that would lead to the loss of essential information. The bandwidth is reduced by separating the interwoven Y and C signals and putting them on tape separately.
When played back, both components are re-mixed to one signal and then transferred to the television set, together with the sound and synchronization signals. In order to achieve this, new video heads and a superior kind of tape were developed, with higher recording density and a smoother tape surface, for optimal head-tape contact. Resolution relates to the number of distinguishable adjacent vertical picture lines. As the vertical picture lines are placed next to each other and virtually placed on a horizontal line, we also speak of horizontal resolution.
Increased horizontal resolution means more detail is visible, resulting in a brighter image, clearer picture lines and smoother image fields. Moreover, a sub-emphasis-circuit suppresses image noise, particularly for weak video signals and also contributes to better image quality. In S-VHS the brightness and color signals Y and C are not combined in the usual manner when played back, and are not sent to the TV as a composite signal, but are transmitted separately.
The result is that the cross color between these signals is largely decreased, which has a positive impact on the color separation. In these cases, the result is good image quality, but not S-VHS quality.
The recorder will then automatically switch to normal VHS. An S-VHS recording cannot be played back on a conventional VHS recorder, because it cannot cope with the increased bandwidth and the other improvements. The result is a distorted black-and-white image. If transmission takes place via normal SCART or HF connection, the image improvement would be less impressive, although still noticeable. Especially when making copies of camcorder recordings, even a third generation copy suffers hardly any quality loss.
A video recorder can be connected to a television set via antenna connection. HF stands for High Frequency. Both devices therefore receive a TV signal. When playing back a recorded videocassette, the video signal is sent to the antenna input of the TV via the same cable. This is possible as the video recorder has a built-in oscillator or small sender , that generates a carrier frequency similar to the frequency of the channel reserved for VCR. The minimum heads required for video and audio registration are two heads for video and one for audio mono.
Three video heads on the head drum allow still picture without distortion and slow motion. With two heads, distortion lines might be visible on the screen, but in case of three heads, the image will be still and without stripes.
Placement of three video heads on the head drum. During recording and normal playback, heads A and B are used. For still picture heads B and B' scan the same video track for noise-free reproduction.
Besides still picture and slow motion, four video heads offers the choice between standard play and long play. Standard Play SP is the cassette's usual playing time. Your family will be amazed when they receive access to these shared files on the cloud. Send one to every member of the family. Get started today be getting your media to Heirloom.
Print a "Self Ship" label and choose the carrier of choice. Or better, buy a "Secure Transfer Kit" and receive all that's needed to get digitized without ever leaving your home. VCR no longer working? In this figure, the light blue bands are individual fields laid down by the recording head of the rotating head drum. Since the drum contains two heads on opposite sides of the drum degrees apart , the two heads alternate, each one reading or writing every other band. The yellow tracks represent the audio and control tracks.
The control track is especially important:. The head is rotating at 1, revolutions per minute rpm , or 30 revolutions per second. In SP mode, the tape is moving past the head at 1. That means that if the video information were being stored linearly, you would need a mile-long km-long tape to store a two-hour movie.
Obviously, the rotating head approach, also known as helical scanning , saves a lot of tape! The only problem this creates is that a VCR designer has to get the video tape to wrap around the rotating head in order to record or play back the tape. In addition, the device has to read the audio and control tracks from the tape, keep the tape moving at exactly the right speed and detect the end of the tape. To do all of this, the tape has to follow a tortuous path, like this:.
Different VCRs use different approaches, but you get the idea. The drive mechanism in the VCR has to extract a good long piece of tape from the cassette and wrap it around a variety of rollers, drums and heads in order to play the tape. It is absolutely amazing that a VCR ever works! Sign up for our Newsletter! Mobile Newsletter banner close.
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