Abstract: A method for decoding an audio signal includes: obtaining a lower-band signal component of an audio signal corresponding to a received code stream when the audio signal switches from a first bandwidth to a second bandwidth which is narrower than the first bandwidth; extending the lower-band signal component to obtain higher-band information; performing a time-varying fadeout process on the higher-band information to obtain a processed higher-band signal component; and synthesizing the processed higher-band signal component and the obtained lower-band signal component. With the methods provided in the embodiments of the invention, when an audio signal has a switch from broadband to narrowband, a series of processes such as bandwidth detection, artificial band extension, time-varying fadeout process, and bandwidth synthesis, may be performed to make the switch to have a smooth transition from a broadband signal to a narrowband signal so that a comfortable listening experience may be achieved.

Abstract: An encoding method includes: extracting core layer characteristic parameters and enhancement layer characteristic parameters of a background noise signal, encoding the core layer characteristic parameters and enhancement layer characteristic parameters to obtain a core layer codestream and an enhancement layer codestream. The disclosure also provides an encoding device, a decoding device and method, an encapsulating method, a reconstructing method, an encoding-decoding system and an encoding-decoding method. By describing the background noise signal with the enhancement layer characteristic parameters, the background noise signal can be processed by using more accurate encoding and decoding method, so as to improve the quality of encoding and decoding the background noise signal.

Abstract: The invention relates to adjustable stop-wagon retarders with locking function for wagons at high speed and disposal methods thereof, which are suitable for railway marshaling yards or rail lines where it is required to prevent wagons from running away, which are hydraulic equipment of no external energy source to automatically regulate wagon's speed and disposal methods of such equipment. The stop-wagon retarder is characterized in that a uni-directional return unit comprising a sealing valve plate and adjustable throttle valve, and a locking control valve composing of switch valve and positioning unit are mounted in the piston assembly, which make the returning speed and the locking speed for wagon at high speed adjustable, thus the aim of setting the retarder with different control levels and thresholds according to the wagon speed is realized.