Apparatus for encoding an NRZ digital signal as a BRZ synchronous FM signal
US4775900A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 18, 1986 |
| Grant date | Oct 4, 1988 |
| Priority date | — |
| Expiry date | Jun 18, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/919
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a multitrack motion analyzer in which video information representing a scene is recorded at a fast frame rate and played back at a slower frame rate, digital data timing and synchronization signals relating to each recorded frame is simultaneously recorded on a separate track as bipolar return to zero (BRZ) FM signals. A Non Return to Zero (NRZ) bit serial digital data signal and synchronous data clock signal are encoded as BRZ digital data signals and then frequency modulated so that the "1" bit, the "0" bit, and the "return to zero" signal levels of the BRZ data signal are converted to three frequencies. The three frequencies are integral multiples and synchronous to the data rate of the NRZ digital data signal so as to eliminate uncertainty between bit boundaries and allow packing more bits per unit time for a given carrier bandwidth. Additionally, accurate synchronization information is recorded and recovered by inserting a missing clock in the BRZ data stream. In a preferred embodiment in which the motion analyzer is operable at different frame rates, the FM frequencies representing the BRZ data signal are chosen to be a function of the ratio between the record frame rate a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.