Abstract: An interface adapter includes an adapter body. An interface converting circuit board, a male connector group electrically connected to the interface converting circuit board, and a female connector group electrically connected to the interface converting circuit board are disposed on the adapter body. The male connector group includes a first male connector and a second male connector. The first connector and the second connector are disposed on a same side surface of the adapter body. A spacing adjusting assembly configured to adjust a spacing between the first connector and the second connector is disposed on the adapter body.

Abstract: A protective case is provided with a connector at an inner side thereof. The connector is used for connecting to an interface of an equipment to be protected. A function module is provided in the protective case and electrically connected with the interface. Ports are provided on one side of the protective case and electrically connected with the connector. It can be connected with the interface of an equipment such as a mobile phone or a tablet computer. An outer side of the protective case is provided with ports that are the same or adaptable with the interfaces of the mobile phone or tablet computer.

Abstract: A transmitter, a receiver, and a signal processing method are provided. The transmitter includes a constellation mapper, a signal conversion module, a digital signal processor, and a digital-to-analog converter. The constellation mapper is configured to determine a mapping relationship between a bit stream and a constellation point in a polar coordinate system, and generate a constellation symbol data flow according to the mapping relationship. The signal conversion module is configured to convert the constellation symbol data flow into an amplitude signal and a phase signal, where the amplitude signal is a 2-level analog signal, and the phase signal is an 8-level digital signal. The digital signal processor is configured to perform digital signal processing on the phase signal, to generate a multi-level digital signal. The digital-to-analog converter is configured to convert the multi-level digital signal into a multi-level analog signal.

Abstract: A transmitter, a receiver, and a signal processing method are provided. The transmitter includes a constellation mapper, a signal conversion module, a digital signal processor, and a digital-to-analog converter. The constellation mapper is configured to determine a mapping relationship between a bit stream and a constellation point in a polar coordinate system, and generate a constellation symbol data flow according to the mapping relationship. The signal conversion module is configured to convert the constellation symbol data flow into an amplitude signal and a phase signal, where the amplitude signal is a 2-level analog signal, and the phase signal is an 8-level digital signal. The digital signal processor is configured to perform digital signal processing on the phase signal, to generate a multi-level digital signal. The digital-to-analog converter is configured to convert the multi-level digital signal into a multi-level analog signal.