Apparatus for synchronizing digital data without using overhead frame bits by using deliberately introduced errors for indicating superframe synchronization of audio signals
US5590161A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 23, 1994 |
| Grant date | Dec 31, 1996 |
| Priority date | — |
| Expiry date | Aug 23, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J3/0602
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A transmitter for transmitting a low probability of detection rf signal, in which digitized audio data is contained therein. Each data frame contains deliberately introduced errors to synchronize a signal containing noise-like data due to skewing of an encoding frame and a data frame upon reception by a receiver. Analog data is converted to digital form by an A/D converter, and then applied to a forward error correction device (FEC encoder) to properly encode the data. One block of input digital data associated with the A/D converter, and one block of input data for creating a codeword associated with FEC encoder are synchronized by a synchronization block, which determines a superframe that constitutes a common multiple of FEC encoder blocks and A/D converter blocks. The superframe is determined by a pulse output from the synchronization block, and that pulse is used to deliberately create one or more errors in the digital data output from the FEC encoder. The error pattern is then detected by a receiver, which constantly monitors the received codewords for the error pattern, and uses the error pattern to synchronize the received input signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.