Amplitude modulation method and broadcasting apparatus for carrying out the method
US5454013A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jun 1, 1993 |
| Grant date | Sep 26, 1995 |
| Priority date | — |
| Expiry date | Jun 1, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/2175
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An amplitude modulation system. An input analog signal indicating audio, etc., is converted into a digital form and the low-order bits of the resultant digital signal are converted into analog form. The resultant analog signal is used to control a gain of an analog controlled amplifier. On the other hand, a plurality of digitally controlled amplifiers are selectively turned on/off in response to the value of the high-order bits of the digital signal. Carrier amplified by the analog controlled amplifier are combined with carriers amplified by the plurality of digitally controlled amplifiers. Comparatively rough amplitude constituents are provided by outputs of the plurality of digitally controlled amplifiers and comparatively fine amplitude constituents are provided by output of the analog controlled amplifier.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.