Abstract: The embodiments of the disclosure discloses an cavity filter in which a sealed resonant cavity is formed by using an adjusting end cover and a body, and a positional relationship between the resonator and the adjusting end cover is changed by using a deformable adjusting end cover. Therefore, during the adjustment of the performance parameters of the cavity filter, the resonant cavity may be kept clean, so as to prevent metal debris or external dust from entering the resonant cavity and affecting the filtering performance of the cavity filter. The adjusting end cover is configured to be driven by the driving body to produce a deformation relative to the resonator. The parameter adjustment range of the cavity filter is improved, so that the cavity filter may adapt to more frequency bands, thereby improving the communication quality of the communication device.

Abstract: The present disclosure relates to a device and a system for testing flatness. The device for testing flatness includes a base, a testing platform, and a ranging sensor. The testing platform is assembled on the base. The testing platform includes a supporting structure. The supporting structure is disposed on the side of the testing platform away from the base and is used to support a to-be-tested board. The structure matches the structure of the to-be-tested board. The ranging sensor is disposed on the side of the testing platform away from the base. After the to-be-tested board is placed on the testing platform, the ranging sensor is used to test distances between a number N of to-be-tested positions on the to-be-tested board and the ranging sensor, to obtain N pieces of distance information, and the N pieces of distance information are used to determine the flatness of the to-be-tested board, where N is an integer greater than 2.

Abstract: A folding device is provided. The folding device includes a bearing and fixing mechanism (1) configured to bear and fix a main body portion (21) of a to-be-folded device (2); a folding mechanism (3) located on at least one side of the bearing and fixing mechanism (1), the folding mechanism (3) being rotatably connected to the bearing and fixing mechanism (1) and configured to bear and fix a to-be-folded portion (22) of the to-be-folded device (2); and a driving mechanism (4) connected to the folding mechanism (3), the driving mechanism (4) being configured to drive the folding mechanism (3) to turn relative to the bearing and fixing mechanism (1), so as to fold the to-be-folded portion (22) to a side in a thickness direction of the main body portion (21). The folding device can fold automatically, and manual folding is avoided.

Abstract: Disclosed are an information interaction method and apparatus, and an electronic device. A specific implementation of the method comprises: acquiring a first near-field communication signal; extracting, from the first near-field communication signal, first pairing information for pairing with a multimedia conference terminal; and sending the first pairing information to a server, so as to instruct the server to determine a target multimedia conference terminal on the basis of the first pairing information and to establish a communication connection between the target multimedia conference terminal and a user terminal device. By means of the implementation, the convenience for a user to control a multimedia conference terminal is improved. In addition, the overall cost of a multimedia conference system can be reduced.