video home system (VHS)
Video Home System (VHS) is the quasi-standard for analog recording of video signals in consumer electronics. The VHS system was developed by JVC in the 1970s and has prevailed over Beta, Video Cassette Recorder( VCR), Video 2000 and others.
VHS records FBAS signals using the helical scan method. The magnetic tape has a width of half an inch, equivalent to 1.27 cm. In addition to the obliquely recorded analog picture information, an audio track is recorded on the upper edge of the magnetic tape and a control track is recorded on the lower edge. The track width for the picture information is about 50 µm and differs slightly for the PAL television standard and for NTSC.
The magnetic tape for VHS recording is contained in a video cassette, which has a mechanical flap to protect the magnetic tape from contact and damage
VHS is available in one version as S-VHS (Super) with significantly improved picture quality, and in another as W-VHS (Wide).
S-VHS records the luninance signal (Y) and a separated chrominance signal (C), known as S-Video or Y/C-Video. Vertical resolution is 400 lines for S-VHS versus 240 lines for VHS. There is also a compact version, VHS-C (Compact), and this compact version is also available in S-VHS quality as S-VHS-C
D-VHS is a digital recording format for digital video in Standard Definition Television( SDTV) and High Definition Television( HDTV) with a resolution of 720 and 1,080 lines. D-VHS uses component video and color subsampling with 8-bit digitization. For video compression, D-VHS uses MPEG-2 and other compression methods. Depending on whether the signals are recorded on high- density( HD) or single-density( SD) magnetic tape, the recordable data rate is over 20 Mbps and about 2 Mbps. D-VHS has not received the necessary market acceptance due to the development of hard disk recorders.
W-VHS was an analog recording format for magnetic tape recording ( VTR) of HDTV. W-VHS recorded one component signal and two audio signals. W-VHS existed for only a short time and was discontinued in the 1990s.
In 1998, Digital Video Home System, D-VHS, the digital version of the VHS system was developed. JVC, Hitachi, Matsushita and Sony were involved in this.