What are the sample rate, the number of quantization bits, and the clock? Part 3
What is the “clock” on a CD?
The CD player contains a biological clock. You may think it is true, but it is a fact. A watch is called a “clock” and it actually carries a crystal oscillator (crystal clock) that keeps accurate time. This is not for the timer. Time is important to read the information recorded on the CD, and the crystal clock, which is the body’s clock, plays an important role. Since this is an extremely high frequency pulse (clock pulse), it splits (slows down the count) and issues the necessary commands to various blocks in the player.
Let’s teach the seeds we are proud of as an ear study. “The clock is related to the pit length of the CD.” For the player to read the 0 and 1 information of the hole, it is necessary that the length of the hole and the time of the biological clock coincide exactly, but for that purpose it is not good. The length of the pit is set to an integral multiple of the clock. There are actually only 9 types of wells on the board, from the shortest (3T) to the longest (9T). You can see that T is a clock pulse and it is a well-researched format.
If the clock is wrong, the sound will be cloudy. This is because the time axis of the pasle fluctuates and jitter occurs. Therefore, the topic of discussion among fans is the external clock. If your body clock is deficient, there are other much more accurate cesium and rubidium clocks. You can use this pulse to move the player! This is why some high-end CD players have an external clock input.
Next time, let’s go over the glossary and how to read the optical disc player specifications that have come out so far.
