What's the sound card?

The sound card consists of various electronic devices and connectors. Electronic devices are used to perform a variety of specific functions. Connectors generally have a socket and a circular jack two, used to connect the input and output signal.

The sound control chip is to obtain the sound analog signal from the input device, and through the Analog-to-digital converter, the acoustic signal is converted into a series of digital signals and sampled and stored in the computer. When replayed, these digital signals are sent to a number-mode converter to revert to the analog waveform, amplified and delivered to the speaker sounder.

Digital Signal Processor

DSP Chip realizes various functions through programming. It can handle voice commands, perform compression and decompression programs, add special sound effects and fax modems. Greatly reduce the burden on the CPU, speeding up the implementation of multimedia software. However, low-grade sound card generally does not install DSP, high-end sound card is equipped with DSP chip.

FM Synthetic Chip

Low-grade sound cards generally use FM composite sound to reduce costs. The function of the FM synthesizer is to produce a synthetic sound.

Waveform Synthesis Table

A sound sample containing the actual music in the Wave table ROM is used for playing midi. In general, medium and high grade sound cards are used wave table, you can get very realistic use effect.

Wave Meter synthesizer chip

The function of the chip is to use the MIDI command to read the sample sounds in the Wave table ROM to synthesize and convert the actual music. Low-grade sound card does not have this chip.

Jumper

Jumpers are settings that are used to set the hardware device of your sound card, including the I/O address of the CD-ROM and the I/O address of the sound The game port settings (on or off) on the sound card, IRQ (interrupt request number) of the sound card, and DMA channel settings cannot conflict with the settings of other devices on the system, otherwise the sound card will not work or even cause the entire computer to panic.

1) I/O port address

The peripherals to which the PC is connected have an input/output address, or an I/O address. Each device must use a unique I/O address, and the sound card usually has a default I/O address at the factory with an address range of 220h~260h.

2 IRQ (Interrupt request) number

Each external device has a unique interrupt number. The default IRQ number for the sound card sound Blaster is 7, and sound Blaster Pro defaults to 5.

3) DMA Channel

When a sound card records or plays a digital audio, the DMA channel is used to transfer audio data between itself and RAM without CPU intervention to increase the data transfer rate and CPU utilization. The 16-bit sound card has two DMA channels, one for 8-bit audio data, and the other for 16-bit audio data transfer.

4) Joystick Port

There is a joystick connector on the sound card. If a joystick is already attached to the machine, the joystick hop on the sound card should be left in the unused state. Otherwise, 2 joysticks clash with each other.

Working principle

The sound card obtains the sound analog signal from the microphone and converts the acoustic amplitude signal sampling into a serial digital signal through a analog-to-digital converter (ADC), which is stored in the computer. When replayed, these digital signals are sent to the analog converter (DAC), which is reduced to analogue waveform at the same sampling speed, amplified and delivered to the speaker, which is known as pulse coded modulation (PCM) technology.

Main role

(1) It can record a digital sound file. Through the sound card and the corresponding driver's control, collects the signal from the microphone, the recorder and so on the sound source, compresses is stored in the computer system memory or the hard disk

(2) Reduce the hard disk or laser disc compressed digital sound file into high-quality sound signal, amplified by the speaker release

(3) Processing of digitized sound files to achieve a specific audio effect

(4) Control the volume of the audio source, the combination of various sound sources to achieve the function of the reverb

(5) The use of language synthesis technology, through the sound card to read text messages. such as reading English words and sentences, playing music and so on

(6) Has the initial audio recognition function, lets the operator use the password to command the computer work

(7) provides the MIDI function, enables the computer to control many has the MIDI interface the electronic musical instruments. In addition, in the driver's role, the sound card can be stored in the MIDI format files in the corresponding electronic musical instruments, issued a corresponding sound. Enable electronic musical instruments to be commanded by the sound card.