1. Field of the Invention
The present invention relates to a video system, particularly to a video system which uses a small size cassette for reducing a size and a weight of a video tape recorder and is chiefly intended for use in a photographing.
2. Description of Prior Arts
A conventional type of video system is shown in FIG. 1. In this drawing, what is shown as 1 is a video camera and 2 is a VTR, while 3 is a cable. An image photographed by the video camera 1 is converted into NTSC signal by the camera then is sent through the cable 3 to the VTR 2. The VTR 2 converts said NTSC signal, at a time of a reproduction, into a signal which can be reproduced with a television set by a built in RF conversion system.
This type of VTR used in a portable video system has such function to record images at a magnetic tape within a magnetic tape cassette and reproduce the image out of said tape. And as an image recording signal therefor, NTSC signals from a video camera and NTSC signals from a television broadcasting station are used. Also output signals reproduced in this type of video system are VHF signals obtained by a frequency modulation of the NTSC signals to VHF band, so that they can be reproduced at a home use TV set having no video input terminal using one of the channels of said TV set. As a VTR having such reproduction function, contains a servo-system for reproduction, a power source, a device to convert reproducing signals to NTSC signals, and an RF conversion system to make a frequency modulation for the NTSC signals, such problems are unavoidable as inconvenience in a portable characteristic and a maneuverability in respect to a size and a weight, etc. of a VTR itself.
Also as a conventional video tape recorder, such system has been known that after a power source switch is put in before a recording is started, a recording button or a reproduction button is pressed to take out a tape out of a cassette and the tape is wound around a cylindrical tape guide having a rotating head being built in the same (hereinafter called as loading), then said loading is stopped by an output of a loading completion detecting switch. Also as a stop button is pressed upon completion of a recording, the above-mentioned recording or reproduction button is reset. At this time, a function to separate the tape from the cylindrical tape guide and house the same in the cassette (hereinafter called as unloading) is carried out. This function is carried out only when an unloading completion detecting switch has not detected an unloading completion and the stop button is pressed.
However, when such complicated arrangement is employed, not only a mechanism within a video tape recorder becomes complicated but there will be many elements not being necessary for operating the system, thus being detrimental in reducing a size and a weight of the system.