Structure of video recorder

The camera is mainly composed of five parts.

1. Optical lens part: image and focus the subject on the camera tube or CCD (a photoelectric conversion device with the same function as the camera tube but more advanced than the camera tube). The function of the optical lens of a camera is exactly the same as that of the lens of a camera and an electric shadow camera. In order to shoot different TV pictures such as panorama and close-up without moving the camera position or moving the camera position less, the camera lens generally has zoom function. In order to make the zoom even and smooth, an electric zoom device is attached to the lens.

2. photoelectric conversion part (sensor): this is the heart part of the camera, which converts the optical signal from the lens into an electrical signal. In the past, cameras were used as sensors, but in recent years, more advanced charge coupled devices (CCD) have been used.

3. Image signal processing part: Its function is to amplify, correct and process the weak current signal to form a full TV signal that meets the requirements of the TV system.

4. image finder: The image finder is actually a small TV monitor, which provides the cameraman with the shot scenes or replayed images. The viewfinder is equipped with various indicator lights to show the working state of the camera (and the video recorder connected to it).

5. Automatic control part: it has various automatic functions such as automatic aperture, automatic focusing, automatic working state data display, automatic alarm and so on. The purpose of setting various automatic functions is to simplify the operation procedures to the greatest extent, so that the camera will not have technical errors because of one thing. Household cameras have more automatic functions than professional cameras, which is for the convenience of untrained users. At present, all home cameras are fully automatic, and the operator only needs to press the recording switch. Because the accuracy of various automatic adjustments is sometimes not very high, the adjustment takes a certain time or the object of adjustment is not necessarily the target set by the photographer (for example, autofocus usually aims at the scene closest to the camera). In the field of professional photography, in order to achieve high accuracy and meet the photographer's subjective wishes, many operations are done manually. There are many adjustments and operations of professional cameras, both automatic and manual, and even some items are only manual and not automatic, such as focusing. So the camera is not as automatic as possible.

The operation process of different types of cameras can be different, so before using unfamiliar equipment, read the instructions of relevant equipment carefully and follow the instructions and steps.

Video recorder is a kind of equipment that can record and restore the video signal output by camera. Because the carrier of the signal is a video tape, this kind of video recording is also called tape recording. Video recorders satisfy people's desire to make, edit, save, copy and exchange images and sound signals in a popular way.

Video recorder is a complex electromechanical equipment, which generally consists of mechanical system, servo system, video signal processing system, audio signal processing system and control system.

1. Mechanical system: The mechanical system mainly includes transportation mechanism and loading mechanism, which provides mechanical guarantee for stable transportation, loading and unloading. When recording, its function is to make the video tape reach the take-up reel from the supply reel through a certain path, and on the basis of ensuring the stability and accuracy of the video tape, the recording signal is recorded on the video tape according to a certain format. When playing, its function is to make the magnetic head track the recording track, so as to complete the signal pickup and recovery. Magnetic head is an electromagnetic conversion device. When recording, the magnetic head converts the electrical signal into a magnetic signal and records it on the video tape. In the process of playing, the magnetic signals recorded on the video tape are converted into electrical signals by the magnetic head. The video head is mounted on a rotatable cylindrical magnetic drum.

2. Servo system: The servo system provides servo voltage and driving voltage for the drum motor and capstan motor, so that the drum motor and capstan motor can rotate evenly and stably, and the drum can rotate evenly and stably, so that the recorded tracks can meet the standards and specifications, and can be replayed at the same speed.

3. Video signal processing system: It includes two parts: luminance signal and chrominance signal. The main function is to process the video signal to be recorded into a recordable signal according to the recording mode and specification, and restore the recorded signal to a standard video signal during playback.

Audio signal processing system: This is a system that processes sound signals, and its function is the same as that of a tape recorder.

Verb (abbreviation of verb) control system: The control system is composed of sensors, control switches, logic control circuits and various actuators, and it is the central command system of the video recorder. It has three functions: first, according to the operator's instructions, it controls the mechanical system to work according to the requirements and prescribed procedures; Second, when the video reaches the terminal or the beginning, it can automatically stop and stand by; Third, when the video recorder fails, it can automatically stop the work of the video recorder.

Home video recorders are usually equipped with tuners and RF converters. TV programs can be received through a tuner. The RF converter modulates the video and audio signals in the video recorder to the TV transmission frequency, and outputs them from the RF output socket for the TV to watch directly.

At present, non-professional TV stations generally use VHS (Video Home System) format video recorders, commonly known as large 1/2 video recorders, and use large 1/2 inch video tapes. Because there are many home video recorders of this specification, the exchange of home video tapes is generally based on VHS specification.

Cameras and video recorders belong to advanced precision instruments and equipment, and should be kept well when used. Proper use and maintenance can prevent or reduce failures and prolong service life. When using and maintaining cameras and video recorders, we should pay attention to the following points:

1. Please don't place and use the equipment where there is oil smoke, water vapor, heating appliances, strong magnetic field, humidity, flying dust and direct sunlight. Due to the influence of strong magnetic field, humidity, dust and other unfavorable factors, important parts of the equipment will be damaged.

Second, the desktop video recorder should be used in a horizontal position. If it is used in an inclined or unstable state, it will bring bad consequences to the video recorder.

Thirdly, in order to prevent the internal temperature of the machine from rising, there are many small holes in the shell of the video recorder for heat dissipation. Therefore, do not cover these small holes or use the equipment in poorly ventilated places.

Four, to prevent foreign bodies or liquids from entering the equipment. Once this happens, cut off the power immediately. If the situation is not serious, you can remove it by yourself. If the situation is serious, it should be sent to a professional department for repair.

Five, when using a video recorder, should avoid suddenly moving the equipment to a place where the temperature and humidity are quite different. If this leads to condensation in the tape and video recorder, the video recorder will automatically stop working and heat up to drive away the tide (usually for several hours).

6. Avoid using inferior videos or very old videos. Because this kind of tape will fall off during use and block the video head. Once the head is blocked, clean it in the right way.

Seven, should avoid strong vibration when using, otherwise it may damage the equipment.

Eight, when the camera is not in use, cover the lens to protect the lens from pollution. When the lens is covered with dust or other dirt, you can blow off the dust or dirt with a balloon. If it can't be completely removed, you can gently brush off dust or dirt with a high-quality lens brush, and then blow it with a balloon. In addition, you can also gently wipe the optical lens with clean deerskin to avoid damaging the lens.

Nine, the camera using the camera tube can not shoot sunlight or other objects that emit strong light, otherwise it will permanently damage the camera tube. When using CCD camera, although you can shoot objects under strong light, it is best not to shoot for a long time.

X. The viewfinder cannot be aimed directly at the sun. Because the magnifying glass of the viewfinder can concentrate light, it will damage the viewfinder when it is aimed at the sun.

Eleven, the shell of the equipment should be kept clean, usually can be wiped with a soft dry cloth, but don't use some chemical reagents to clean.