With the increasing improvement of people's living standards, the social demand of choosing advanced recording studio as recording and audio playback equipment is more and more intense. Here, we do not talk about the principle and use of the traditional cassette recorder, but focus on the new functions and new technologies of the new recording equipment.
Because of its small size, cassette tape recorders often adopt the design of two heads, that is, erasing head, recording / playback combined head, guide wheel and clamping wheel are installed on a sliding plate in turn. Although this design takes space constraints into account, it will cause the following two problems:
First of all, the gap of the recording head is generally 0.01mm, while that of the playback head is much smaller. The production is generally 0.0005mm. Now the combined head is used for recording and playback at the same time. The gap of the head can only take a certain intermediate value, such as 0.002mm. Such a compromise data can not produce enough external magnetic field and enough magnetic permeability of the tape, which makes the recording effect unstable; However, due to the low speed, large gap and limited high frequency response, the width of frequency response is affected, especially the high frequency response becomes worse. IC card holder.
Secondly, due to different work requirements, the material of the magnetic head should be different. The recording should be made of ferrite, and the playback head should be made of iron, silicon, aluminum and other high permeability alloy swallows. Now, if ferrite material is used after recording / playing combination, because the porous structure is randomly distributed on the surface of ferrite, the IC card tape of card holder will emit relatively large random noise (irregular noise) when playing through this material; if it is all Fe Si Al alloy, it is not cost-effective. Therefore, most of the advanced recording disks adopt three head mode. The card holder SIM, that is, the erasing head and the recording head are made of ferrite, while the playback head is made of permalloy with high permeability. In this way, not only the gap and performance can develop strengths and avoid weaknesses, but also can be recorded while monitoring.