Low cost digital automatic alignment method and apparatus
US5991609A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 26, 1996 |
| Grant date | Nov 23, 1999 |
| Priority date | — |
| Expiry date | Dec 26, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/18
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A technique for the automatic alignment and tuning of the front end of a vehicle radio. A tuning voltage is applied to a multiplying digital-to-analog converter before being applied to a front end tuning circuitry of the radio. A tuning voltage antenna number is applied to the tuning voltage at the converter to scale the tuning voltage, and adjust the center frequency tuning of the front end. During alignment, the tuning voltage antenna number is used to modulate the tuning voltage around a mean by reprogramming the tuning voltage antenna number a few values higher and lower in sequence. This modulation of the antenna tuning voltage creates an AC modulation component on the signal strength indicator signal passing through the front end. The signal strength indicator signal is measured and compared to its value before the tuning voltage antenna number was changed. If the signal strength indicator signal is higher for a higher tuning voltage antenna number, the front end is misaligned to the low side of the desired alignment point. Likewise, if the signal strength indicator signal is lower for an increasing tuning voltage antenna number, the front end is misaligned to the high side. …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.