This trainer is a dynamic demonstrator. It is intended to study how various activities are performed inside a CD player system. While it is difficult to demonstrate all the above mentioned principles, because of the presence of the surface mounted devices, Principle block signals are displayed for waveform observations only. Various faults are introduced in this trainer, wherever possible, like PLAY/PAUSE, FORWARD, SKIP, REVERSE, OPEN and CLOSE, POWER SUPPLY, SMPS etc. In addition to this a hand-held remote control will also be provided. How CD (Compact Disk) player works: Converting sound into numbers:
In a digital recording system, sound is stored and manipulated as a stream of discrete numbers. A microphone connected to a circuit generates the numbers. Each number is called a SAMPLE, and the number of samples taken per second is the SAMPLE RATE. Ultimately, the numbers will be converted back into sound by a DIGITAL TO ANALOG CONVERTER or DAC, connected to a loudspeaker. Once the waveform is faithfully transformed into bits, it is recorded on a Compact Disc. The bits are represented as microscopic pits burned into the plastic by a laser. To read the data, light from a gentler laser is reflected off the surface of the into a light detector. Digital circuits are complex, but very few of the components must be precise; most of the circuitry merely responds to the presence or absence of current. This system is mounted in an ergonomically designed cabinet. All the moving parts are visible for observation. It works on 230V AC power inlet. |
