Abstract: A method and apparatus of video downloading, a method and apparatus of video transmission, a terminal device, a sever and a medium are provided. The method of video downloading includes: acquiring a buffer length; generating a video data downloading request according to the buffer length; and sending the video data downloading request to a server, and downloading target video data according to a received request result returned by the server with respect to the video data downloading request.

Abstract: A subharmonic switching power amplifier architecture includes a power amplifier core that includes at least one power amplifier that receives an input signal and is operable in a power back-off region. Characteristically, the at least one power amplifier is configured to be toggled at a carrier frequency (Fc) when the power level of the input signal is equal to or higher than a predetermined power level and at a subharmonic component of the carrier frequency when the power level of the input signal is less than the predetermined power level. Concurrent harmonic tuning and subharmonic tuning is implemented to enhance the efficiency at both peak power mode and power back-off mode. Characteristically, the power amplifier being configured to be operated by a voltage mode or current mode driver and in the current mode with zero-voltage-switching.

Abstract: A subharmonic switching digital power amplifier system includes a power amplifier core that includes at least one power amplifier operable in a power back-off region and a power supply providing at least one operating voltage to the power amplifier. Characteristically, the power amplifier is toggled at a subharmonic component of a carrier frequency (Fc) to achieve power back-off wherein the power amplifier is operated in a voltage mode or current mode driver. Multi-subharmonics can be used to further enhance the power back-off efficiency. A switching digital power amplifier system employing phase interleaving is also provided.

Abstract: A subharmonic switching digital power amplifier system includes a power amplifier core that includes at least one power amplifier operable in a power back-off region and a power supply providing at least one operating voltage to the power amplifier. Characteristically, the power amplifier is toggled at a subharmonic component of a carrier frequency (Fc) to achieve power back-off wherein the power amplifier is operated in a voltage mode or current mode driver. Multi-subharmonics can be used to further enhance the power back-off efficiency. A switching digital power amplifier system employing phase interleaving is also provided.