This is the true information of the patent:
ApplicationNo.: 99 1058 10.0 Application Date: 1999.04. 19.
Name: Method and device for audio signal sampling rate conversion.
Gong Kai (Announcement)No.: CN 1236222 Date of Publication (Announcement):1999.1.24.
Main classification number Original application number: H03H 17/06:
Classification number H03H 17/06
Release date: priority:1998.5.15ep98108860.2.
Applicant: Germany Thomson-Brandt Co., Ltd.
Address: Flynn-Schwinning, Federal Republic of Germany
Inventor: Juergen Schmidt; Ernst Schrudde's International Application:
International publications: Entry date:
Patent agency: Zhongke Patent and Trademark Agency Co., Ltd. Agent: Liu Xiaofeng.
abstract
Generally, performing the conversion from the higher sampling frequency fs 1 to the lower sampling frequency fs2 will lead to aliasing distortion. Now we know that this aliasing distortion can be avoided by using low-pass filters (called anti-aliasing filters). The effect is to remove the spectral components higher than FS2/2 frequency from the digital signal. According to the present invention, at the time of spectrum decoding, the signal part is limited within the signal bandwidth less than half of the second sampling frequency fs2 to be resampled. This can be used for MPEG encoded signals by limiting decoding to a specific number of subbands, and for Dolby AC-3 encoded signals by setting a specific spectral line to zero at the time of decoding.