How copper and fiber transmit data?
People have been using copper wire for sound and information transmission for a long time. However, the use of fiber optic cables has been increasingly used recently. Due to cost issues, it is not yet possible to replace all copper wires with fiber. But if you want to convert some of the cables into optical signals, the most important thing is to convert the electrical signals into optical signals and then convert the optical signals into electrical signals.
To use two kinds of diodes to convert electrical signals and optical signals, a semiconductor element such as "diode" is used. However, diodes that convert electrical signals into optical signals and diodes that convert optical signals into electrical signals must be of different types. In other words, two types of diodes are required to connect the copper wire and the optical fiber.
In order to convert the electrical signal transmitted by the copper wire into an optical signal, a "laser diode" is used. Laser diodes are made of a semiconductor called “GaAs,†which produces light of a specific wavelength after pressurization.
When copper signals are used to transmit digital signals such as “1†and “0â€, the high voltage and low voltage conditions generally correspond to “1†and “0â€, respectively. When the transmitted signal voltage is applied to the laser diode and converted into an optical signal, light is generated or disappears. If the luminescence state and the disappearance state are respectively set to "1" and "0", digital data can be transmitted through the optical fiber.
If the optical signal transmitted from the optical fiber is reduced to an electrical signal, a "photodiode" is used. One of the properties of this type of diode is that it produces a current that is proportional to the light intensity when exposed to light. When the optical signal transmitted by the optical fiber passes through the photodiode, it can be directly converted into an electrical signal.
2, the combination of fiber and coaxial
With the technology of converting electric signals and optical signals to each other, high-speed networks can be established at a low cost by effectively using optical fibers and copper wires.
CATV is one of the representatives. In order to send television programs, a coaxial line made of copper wire is used to connect thousands of households to CATV stations. Recently, the Internet connection has been started and applied to local telephones. The speed is higher, the number of channels is increasing, and two-way communication has begun to be realized.
It is difficult to transmit high-frequency electrical signals over long distances on coaxial lines. Therefore, in order to increase the communication distance, a large number of amplifiers must be used, and the cost will increase accordingly.
If optical fibers are used instead of coaxial cables, the communication speed of the CATV network can be increased without using an excessive number of amplifiers. But if you want to introduce fiber into each user's home, the cost will increase.
Therefore, a relay device is installed between the CATV television station and the user's home, and the cable between the CATV television station and the relay device is replaced with an optical fiber. Diode photo-electric converters (O/E) and electro-optic converters (E/O) are used in relay devices. The original coaxial cable is still used structurally in a shorter area between the relay device and the user's home.
As a result, the trunk line portion can support broadband transmission and multiple channels, and the portion between the relay device and the user's home does not need any change, so it will not increase the cost.
1.2 The LED contains chips of two or three colors.
1.3 Colored or colorless, light-emitting diodes of the above colors can also be divided into four types: colored transparent, colorless transparent, colored scattering and colorless scattering. Scattered light emitting diode and LED can be used as indicator light.
Colloid appearance: colorless transparency, colored transparency, colored scattering, colorless scattering, etc;
Straight LED Lamp Beads are divided according to the specifications:
2.1 Shape: round lamp, square lamp, rectangular, surface light emitting tube, side tube, surface mounting microtube, etc.
2.2 Round lamps are divided into φ 2mm. φ 4.4mm. φ 5mm. φ 8mm. φ 10mm and φ 20mm, etc.
2.3 Generally φ 3mm LED is recorded as T-1; hold φ 5mm is recorded as T-1 (3/4); hold φ 4.4mm is recorded as T-1 (1/4).
High directivity: generally, it is a pointed epoxy package, or a package with a metal reflection cavity, without scattering agent. The half-value angle is 5 ° - 20 ° or less, with high directivity, which can be used as local lighting source or combined with light detector to form an automatic detection system;
Smd Led Lamp Beads,Lamp Beads 5050 Rgb,Rgb Smd Lamp Beads,Light Board Patch Led
Dongguan XINYUDA Technology Co., Ltd. , https://www.gdxige.com