With the promotion of the construction of intelligent communities in the country, anti-theft systems have become essential equipment for intelligent communities. Especially in recent years, the urg...[Details]
1. Introduction
RFID (radio frequency identification) is a non-contact automatic identification technology that emerged in the 1990s. It uses the characteristics of radio frequency signal prop...[Details]
As a wireless broadband metropolitan area network standard, WiMAX technology has greater advantages than previous 3.5GHz MMDS products in terms of non-line-of-sight transmission and spectrum utiliz...[Details]
introduction
In the discharge process of tokamak plasma physics, the study of rupture and sawtooth is of great significance. Rupture and sawtooth exist in most tokamaks. Rupture is a notew...[Details]
Electronic systems are located at different points on the automotive power bus and therefore often need to operate under very stringent power requirements. These include load dump, cold crank, very lo...[Details]
Battery life is critical for portable applications. For applications such as smoke detectors, security devices, and thermostats, factory-installed batteries need to last for more than 10 years. The...[Details]
1. Introduction
Testing the temperature of steel billets before rolling is an important measure to ensure the quality of steel. Traditional manual testing is difficult to ensure product qu...[Details]
In recent years, with the rapid development of the information industry, dot matrix LED display screens have been widely used in various advertising and information display systems such as the fina...[Details]
We know that the inverter consists of two parts: the main circuit and the control circuit. Due to the nonlinearity of the main circuit (switching action), the inverter itself is a source of harmoni...[Details]
Today, the value of electronic components in cars accounts for 15-20% of the total vehicle. In the future, this proportion may be as high as 30-40% as more safety electronics, fuel consumption and ...[Details]
hint:
The number of speakers and their spacing limit the sound field of a portable stereo system.
Spatial audio attempts to artificially recreate the experience of listening to sounds i...[Details]
The rectified DC voltage is then converted back to AC using power electronics such as insulated gate bipolar transistors.
The output voltage is switched on and off at a high frequency, control...[Details]
1 Basic Features
In computer control systems and various intelligent instruments and meters composed of single-chip microcomputers (or microprocessors), various external analog signals must be ...[Details]
1 Introduction
Ultrasound refers to elastic vibration with a frequency higher than the audible frequency limit (i.e., in the frequency band above 20 kHz). The propagation process of this vib...[Details]
0 Introduction
Ultrasonic waves
are mechanical waves with a frequency of more than 20KHz, and the propagation speed in the air is about 340 m/s (at 20°C). Ultrasonic waves can be gene...[Details]