Sintered Type Nickel Cadmium Battery
Established in 1956, during the China first five-year-plan, Henan Xintaihang Power Source Co., Ltd. (Factory No.755) was the first R&D and manufacturing enterprise in China in the field of alkaline storage batteries and modular power system and it was also the military factory which owned the most varieties rechargeable batteries in domestic. Taihang was located in national Chemistry and Physicals Power Source Industrial Park, Xinxiang City, Henan, China.
Extra High Dishcharge Rate Nickel Cadmium Battery, KPX10 ~ KPX240, Max. discharge current ＜10C
The nickel–cadmium battery (NiCd battery or NiCad battery) is a type of rechargeable battery using nickel oxide hydroxide and metallic cadmium as electrodes. The abbreviation NiCd is derived from the chemical symbols of nickel (Ni) and cadmium (Cd).
Nickel Cadmium Battery,Starting Battery,Nickel Cadmium Battery Aircraft,Nickel Cadmium Battery For Metro Henan Xintaihang Power Source Co.,Ltd , https://www.taihangbattery.com
Design techniques for distributed fiber inspection systems that learn less with less
Optical fiber detection systems have traditionally relied on microcontroller (MCU) architectures. While MCUs or digital signal processors (DSPs) are effective in handling digital signal processing, they face challenges when it comes to high-speed real-time data acquisition. This limitation can lead to accumulated measurement errors due to limited sampling points. To address these issues, this design introduces a fast fiber inspection system based on the fundamental principles of fiber optics. The system employs an FPGA (Field-Programmable Gate Array) for data processing, enabling efficient and accurate high-speed data acquisition.
Optical fiber communication is a modern technology that uses optical fibers as transmission media and light waves as carriers to transmit information. Compared to traditional electrical communication, fiber-optic sensing offers several advantages, including high precision, sensitivity, resistance to electromagnetic interference, long lifespan, corrosion resistance, low cost, minimal signal loss, and the ability to support long-distance transmission.
Despite its many benefits, fiber-optic communication still has some inherent limitations. For instance, optical fibers are fragile and prone to breaking, with limited mechanical strength and a minimum bend radius requirement. Powering the system can be challenging, and coupling and splicing operations are not always flexible. Additionally, fiber cuts and connections require specialized tools and equipment. External factors such as urban development, flooding, human damage, or natural disasters can easily disrupt fiber lines. Ensuring the reliability of fiber-optic communication systems remains a key technical challenge. This design addresses these issues by improving the reliability of fiber-optic monitoring systems using an FPGA-based architecture, which enhances data acquisition accuracy, reduces measurement errors, and ensures high operational reliability.
**1. Measurement Principle of Optical Fiber Communication System**
In current fiber optic testing, the primary focus is on measuring fiber loss and break points. These measurements rely on two main optical phenomena: Rayleigh scattering and Fresnel reflection. Rayleigh scattering is an intrinsic property of the fiber material, caused by impurities and core additions, leading to backscattering along the entire length of the fiber. On the other hand, Fresnel reflection occurs at interfaces where the fiber meets air or at joints like mechanical splices. Therefore, fiber loss is typically measured using Rayleigh scattering, while break points are identified through Fresnel reflection.
The Rayleigh scattering loss can be approximated by the following formula:
$$ \text{Loss} = A + B \lambda^{-4} $$
Where λ is the wavelength in micrometers, and A and B are constants related to the material composition of the fiber.
The intensity of Fresnel reflected light depends on the condition of the reflecting surface and the power of the transmitted light. The optical power $ P_f(L) $ measured at the injection end from a point L on the fiber is given by:
$$ P_f(L) = P_0 R e^{-\beta L} $$
Where L is the distance from the reflection point, R is the reflection coefficient, $ P_0 $ is the peak injected power, and β is the fiber attenuation constant.
**2. Hardware Design**
Figure 1 illustrates the system’s hardware configuration. An electric pulse generated by a pulser drives the light source module to emit a light pulse, which is injected into the fiber under test via a directional coupler. As the pulse travels through the fiber, Rayleigh scattering occurs, and Fresnel reflections appear at any irregularities or breaks. These reflections return to the coupler and are detected by a photodiode. The resulting electrical signal is amplified, converted to digital form, and sent to the data processing module. Due to the weak nature of the reflected signals, multiple pulses are transmitted, collected, and averaged to improve accuracy. OTDR (Optical Time Domain Reflectometer) systems use this principle to measure fiber characteristics.
**2.1 Data Acquisition and Processing Module**
This module includes an FPGA (EP3C35Q240C8), an ADC, and SRAM memory, responsible for real-time data collection and processing. The FPGA is configured using AS mode, where the configuration file is stored in an external EPCS16 chip. Upon power-up, the FPGA automatically loads the configuration from the chip and stores it in its internal SRAM. This setup allows for reliable and efficient operation during testing and debugging.
**2.2 Data Transceiver Module**
The transceiver module sends optical pulses into the fiber and receives the reflected signals. The FPGA generates a pulse, which is amplified by a driver circuit and converted into a light pulse by a photoelectric device. The pulse is then injected into the fiber, and the reflected signals are captured by the coupler and sent to the photodetector. The optical signal is converted back to an electrical signal, amplified, and processed by the data acquisition module. The TPS2817 MOSFET driver is used for high-speed pulse amplification, ensuring sufficient power for the optical signal.
**3. Test Results and Analysis**
The system emits an optical pulse, which reflects upon encountering breaks, joints, or fusion points. By accurately measuring the echo time, the distance to the event can be calculated using the formula:
$$ L = \frac{c t}{2n} $$
Where c is the speed of light, t is the round-trip time, and n is the refractive index of the fiber. The test results show the relative optical power measured at different fiber lengths. Events such as melting joints and microbends cause losses but no reflection, appearing as sudden drops in the backscatter level. Active connectors, mechanical splices, and breaks, however, result in both loss and reflection, with the magnitude of reflection determined by the peak height on the backscatter curve.