Traditional carrier digitization scheme

Traditional carrier archives need to be digitized, taking the utilization demand and carrier protection as the premise.

Digitization is the process of converting information into digital (that is, computer readable) format, which refers to converting any continuously changing input, such as the lines of a picture, into a series of separate units, which are represented by 0 and 1 in the computer. This conversion is usually done by an analog-to-digital converter.

Digitalization is to convert many complicated and changeable information into measurable numbers and data, and then use these numbers and data to build a suitable digital model, and then convert them into a series of binary codes and introduce them into a computer for unified processing. This is the basic process of digitalization.

Advantages:

1. Compared with analog signals, digital signals are processing signals. The processed signal has good stability to the external environment and the circuit conditions with clutter and distortion. It can be said that digital signals are suitable for video recorders and long-distance transmission which are prone to clutter and waveform distortion. Digital signal transmission has the advantages of good stability and high reliability.

2. Do digital signals need integrated circuits (IC) and large-scale integrated circuits (ISI)? [2], and computers can easily process digital signals. Digital signals are also suitable for digital stunts and image processing.

3. The digital signal processing circuit is simple. It has no various adjustments in analog circuits, so the circuit works stably and technicians can be liberated from daily adjustment work. For example, in an analog camera, it is necessary to use more than 100 variable resistors. In some places, while adjusting these variable resistors, it is necessary to adjust the shooting characteristics of the camera.

Various adjustments have a subtle influence on each other, and need to be adjusted repeatedly to make the camera close to perfect working condition. In TV broadcasting equipment, the camera is still a relatively small electronic equipment. If the camera is 100% digital, there is no need to adjust it. For manufacturers, the cost of cameras is reduced. For TV stations, skilled engineers are not needed, and the program production time is shortened.

4. Digital signals are easy to compress. This is the main advantage of digital cameras.

Disadvantages:

1. Compared with the analog signal, the digital signal itself is less affected by external clutter, but it can't identify the clutter of the analog signal itself converted into digital signal. Therefore, an analog-to-digital (A/D) converter for converting an analog signal into a digital signal cannot distinguish an image signal from clutter.

2. Digital processing will damage the image quality. In other words, after analog → digital → analog processing, the image quality will be reduced to some extent. Strictly speaking, when a digital signal is restored to an analog signal, it will be damaged compared with the original analog signal. This is closely related to the following shortcomings.

3. After the analog signal is digitized, the amount of information will explode. In order to digitize an analog signal with a bandwidth of (f), it is necessary to sample at a frequency of about (2f+α), and the image signal must be quantized with 8 bits (bits are unit pulse signals).

Specifically, if the bandwidth of the image signal is 5MHz, at least13x106 to14x106 times (13M to 14M times) need to be sampled, and 8 bits need to be used to represent the digitized signal. Therefore, the total number of digital signals is about 1 100 million bits per second (1000 bits). Not to mention that this is an astronomical figure, in terms of its capacity, it is also difficult for integrated circuits to handle.

So this problem is no longer a problem of digitalization itself. However, in order to improve the quality of digital images, it is necessary to further increase the amount of information. This is a difficult problem that digital technology needs to solve, and it is also the basic problem of digital signal.