Device and system for shielding effectiveness detection

Abstract

The invention provides a signal emitter for shielding effectiveness detection. The signal emitter comprises a signal source, a signal amplifying module, an antenna and a power supply, wherein a two-stage amplifying circuit is adopted as the signal amplifying module. The invention further provides a shielding effectiveness detection system which comprises the signal emitter and a signal receiver. The signal emitter is used for generating a ratio-frequency signal needed by detection and emitting the ratio-frequency signal out, and the signal receiver receives the signal after the signal is damped by a detected shielding body, processes the signal and then feeds the signal back to a user. According to the shielding effectiveness detection system, the dynamic detection range for electromagnetic interference within the frequency band of 1 MHz-100 MHz can reach 100 dB or above.

Description

technical field [0001] The invention relates to the field of electromagnetic shielding testing, in particular to a device and system for testing shielding effectiveness. Background technique [0002] Magnetic resonance imaging technology is a widely used medical imaging diagnostic technology. Its basic principle is to place the human body in a special magnetic field, and use radio frequency pulses to excite the hydrogen nuclei in the human body, causing the hydrogen nuclei to resonate and absorb energy. After the radio frequency pulse is stopped, the hydrogen nucleus emits a radio signal at a specific frequency, and releases the absorbed energy, which is collected by the receiver outside the body, and the image is obtained through computer processing. The shielding material is used to shield the electromagnetic radiation interference from the outside world. [0003] With the development of electronic technology, the sensitivity of the receiver of the nuclear magnetic resona...

AI Technical Summary

Problems solved by technology

In nuclear magnetic resonance inspection, the main shielding interference signal is low-frequency electromagnetic signal, and in the prior art, the signal strength of the shielding effectiveness test for low-frequency electromagnetic signal below 100MHz is generally only 60-70dB, which cannot meet the needs of shielding materials. High shielding effectiveness test requirements, so a low-frequency electromagnetic signal shielding effectiveness detection system with a large dynamic range is required

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