How a tape recorder turns a magnetic signal into an acoustic signal

The data in the audio tape actually converts the analog signal of the voice into digital information represented by 0 and 1 through PCM (pulse code modulation), and in the case 0 and 1 are represented by the physical state of the magnetic material. When the tape is to be taped, the magnetic head will convert the information of the tape into a tight pulse signal, and then form a vibration in the horn, so it is reverted to a sound signal, because the pulse is very tight (8000 per second), so the human ear will not distinguish the difference between the signal and the real sound.

Words of approval.

The tape recorder uses the principle of electromagnetic induction to convert the original recorded analog magnetic signal on the tape into an analog electrical signal through the magnetic head, and then amplifies it to a certain amplitude through the audio amplifier, and then pushes the speaker voice coil to restore the analog electrical signal into sound.

The recording and playback of a tape recorder is an electrical-magnetic conversion process. When recording, the audio electrical signal is amplified and then transmitted.

When the head coil is inserted, an alternating magnetic flux is generated in the core of the head, which forms a change with the audio at the working gap of the head.

When the magnetic tape is pressed through the gap in the magnetic head, the magnetic field lines pass through the magnetic layer on the tape, magnetizing it, thus facilitating.

Residual magnetism is left behind, and as the tape moves at a constant speed, it leaves on the tape a continuity of polarity and strength as the audio signal changes.

remanence traces), so that the acoustic signal is recorded in the form of remanence. When playing back, when recording a tape with magnetic tracks to phase the recording.

When the same speed passes through the working gap of the head, the magnetic remanence on the tape is much higher because the permeability of the core of the head is much higher than that of air.

The magnetic field lines of the field will pass through the core of the magnetic head to form a closed magnetic circuit. Because the remanence strength and direction on the tape are all with the recorded sound signal.

Electromotive force.

The recording principle of the tape recorder is: when recording, the microphone first converts the sound into a current with varying strengths, that is, the acoustic signal is converted into an electrical signal, which is the use of electromagnetic induction;

As can be seen from the figure, the recording head is a hoof-shaped electromagnet, and its magnetic strength will change with the electrical signal, converting the electrical signal into a magnetic signal, and using the magnetic effect of the delayed current

So the answer is: electromagnetic induction; Magnetic

When recording, the sound of this tape is first converted into a current with a change in strength, and such a current is used to make the recording head through the recording head, which produces a magnetic field with a change in strength When the tape slides over, the small particles on the tape are magnetized by different levels of intensity, so a series of information about the change in magnetic properties is recorded Recording technology converts electrical signals into magnetic signals, using the principle of magnetic effect of electric current;

So the answer is: magnetic field; Magnetic current