AVI system with improved receiver signal processing
US8374573B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 30, 2009 |
| Grant date | Feb 12, 2013 |
| Priority date | — |
| Expiry date | Aug 15, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08G1/042
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An automatic vehicle identification (AVI) system signal processing technique which provides improved performance and reliability and which substantially eliminates the adverse effect of ambient noise signals on the detection of permissible code sequences by an AVI receiver. Input signals to an AVI receiver are filtered to strip off all frequency components except those at the carrier frequency. The filtered signals are subjected to variable gain amplification over a substantially linear operating range with the maximum amplitude of the amplified signals limited to a maximum value below the supply voltage and within the linear range of the variable gain amplifier. The amplified signals are converted to a binary pulse train signifying the temporal length of each active carrier period and the temporal length of each quiescent carrier period. The binary pulse train is decoded and a valid vehicle signal is generated if the decoded binary pulse train matches a permissible code sequence.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.