A tape recorder, tape deck, reel-to-reel tape deck, cassette deck or tape machine is an audio storage device that records and plays back sound using magnetic tape, either wound on a reel or in a cassette, for storage. It records a fluctuating signal by moving the tape across a tape head that polarizes the magnetic domains in the tape in proportion to the audio signal.
History
Early tape recorders were created by replacing the steel wire of a wire recorder with a thin steel tape. The first of these modified wire recorders was the Blattnerphone, created in 1929 or 1930 by the Ludwig Blattner Picture Corporation. The first practical tape recorder was called K1 and demonstrated in Germany in 1935. Friedrich Matthias of IG Farben/BASF developed the recording tape, including the oxide, the binder, and the backing material. Development of magnetic tape recorders in the late 1940s and early 1950s is associated with the Brush Development Company and its licensee, Ampex; the equally important development of magnetic tape media itself was led by Minnesota Mining and Manufacturing Company (now known as 3M).
History:
Electrical
Electric current flowing in the coils of the tape head creates a fluctuating magnetic field. This causes the magnetic material on the tape, which is moving past and in contact with the head, to align in a manner proportional to the original signal. The signal can be reproduced by running the tape back across the tape head, where the reverse process occurs – the magnetic imprint on the tape induces a small current in the read head which approximates the original signal and is then amplified for playback. Many tape recorders are capable of recording and playing back at once by means of separate record and playback heads in line or combined in one unit.
Electric current flowing in the coils of the tape head creates a fluctuating magnetic field. This causes the magnetic material on the tape, which is moving past and in contact with the head, to align in a manner proportional to the original signal. The signal can be reproduced by running the tape back across the tape head, where the reverse process occurs – the magnetic imprint on the tape induces a small current in the read head which approximates the original signal and is then amplified for playback. Many tape recorders are capable of recording and playing back at once by means of separate record and playback heads in line or combined in one unit.
Mechanical
Modern professional recorders usually use a three-motor scheme. One motor with a constant rotation speed provides traction for the capstan. This, usually combined with a rubber pinch roller, ensures that the tape speed does not fluctuate. Of the other two motors, one applies a very light torque to the supply reel, and the other a greater torque to the takeup reel, to maintain the tape's tension. During fast winding operation the pinch roller is disengaged and the reel motors provide the necessary power. The cheapest models use a single motor for all required functions, coupled to the capstan and reel spindles as needed with mechanical clutches and belts. There are also variants with two motors, in which one motor is used for rewinding only.
Modern professional recorders usually use a three-motor scheme. One motor with a constant rotation speed provides traction for the capstan. This, usually combined with a rubber pinch roller, ensures that the tape speed does not fluctuate. Of the other two motors, one applies a very light torque to the supply reel, and the other a greater torque to the takeup reel, to maintain the tape's tension. During fast winding operation the pinch roller is disengaged and the reel motors provide the necessary power. The cheapest models use a single motor for all required functions, coupled to the capstan and reel spindles as needed with mechanical clutches and belts. There are also variants with two motors, in which one motor is used for rewinding only.
No comments:
Post a Comment