Fm data recording and playback method and apparatus

Abstract

A method and apparatus for recording a data signal and for playing it back at a variable speed ratio including a recording unit, a playback unit and a speed control unit. A modulated carrier wave is first recorded and subsequently played back at a different speed from the recorded speed. A recording speed control signal controls the recording speed through the speed control unit, and a part of the speed control signal is recorded simultaneously with a data signal from a miniature test model on a record medium, such as a magnetic tape, by a write unit, such as a recording head, after being operated on by the data signal. The playback speed is controlled by a playback speed control signal at a variable speed ratio, so that it is possible to achieve any speed ratio, such as .sqroot.10, etc., between the recording speed and the playback speed. The speed ratio is directly proportional to the size ratio between the size of the miniature test model and the actual physical size of the structure such as a building, dam or the like. The recorded signal is operated on by a speed signal when it is played back and is reproduced by a read unit such as a reproducing head. Thus, the desired data signal at a desired speed ratio can be read out when being played back.