MP3 Walkman is a kind of digital audio equipment which can store, decode and play MP3 music files without computer support. It uses sufficient power supply and has special components to store, organize and play digital music files and display playback information. Before playing, we must create digital music files and download them to the memory of the walkman.
The heart of any MP3 Walkman is DSP (digital signal processor). DSP is in charge of data transmission, device interface control, file decoding and playback of Walkman. DSP can complete a variety of processing tasks in a very short time, and this process consumes very little energy.
How MP3 Player works?
When we start to create and download digital music files from PC, DSP starts to work. When creating files in MP3 format (or other digital audio formats, such as wma, AAC), the creation tool software used will process the file to make it smaller. This work process is lossy compression.
The internal storage space (used to store digital music files) is the biggest problem of MP3 Walkman. After compression, MP3 files will become smaller. From the level of compression used, we can get some information about how many kilobytes per second it is generally expressed. However, the higher is the compression ratio, the worse is the sound quality. Generally, MP3 uses 128 Kbps compression ratio. To play a song with MP3 player, it must be stored in the Walkman's memory. If the Walkman has only built-in memory, it is necessary to connect the player with the USB interface, serial port or parallel port of the PC, and then transfer MP3 files from the hard disk of the PC to the memory of the device. If the Walkman has removable storage media, we can directly copy files to the storage media, which is faster than transferring files through USB interface. Many stereo systems that can play MP3 files also have a built-in decoder. This decoder can read files directly from CDs, and some can also be directly compressed into digital music files to be stored in memory, so there is no need for PC to complete the compression task.
When you select an MP3 song from the built-in memory (using the built-in controller of the Walkman, the information will be displayed on its LCD screen, such as track, singer and playing time), and the file data will be transmitted to the DSP, which will decompress the file. The required decompression software is placed in the processor or stored in memory. Then the DSP will process the data to a / D converter, it will convert the binary digital information into analog audio signal, and then output to the headphones and speakers. Some players also have a small preamplifier circuit, which can amplify the audio signal output from the converter and then output it to the headphone jack.
5 Steps of the Operating Principle:
Step One: Read the flash signal.
Step Two: Decode (or decompress) the signal to the decoding chip.
Step Three: Convert the solved digital signal into analog signal through digital to analog converter.
Step Four: Amplify the converted analog audio.
Step Five: After low-pass filtering, it goes to the headphone output port.
MP3 Circuit Mainly Includes:
Data port, memory, microprocessor, decoder, DAC, display screen, playback and function control, audio port, amplifier, power supply, headphone output and other parts. It can be divided into three parts: Signal processing, control circuit, power processing.