Instantaneous deviation limiter with pre-emphasis and zero average value
US4802236A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 30, 1986 |
| Grant date | Jan 31, 1989 |
| Priority date | — |
| Expiry date | Dec 30, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03C3/09
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A modulation limiter that eliminates over-deviation otherwise caused by asymmetrical modulation signals in a frequency modulated (FM) transmitter. The output signal from a conventional modulation clipper is integrated, multiplied by a gain constant, and subtracted from the input, which causes the clipper output to have zero average and a high-pass frequency response with a time constant determined by the feedback gain. The zero average value allows the clipped modulation signal to be coupled to a modulator without over-deviation caused by shifts in the average value of the clipped signal, and the high-pass response can be used to give the modulation signal pre-emphasis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.