Modem for modulating and demodulating main signal and secondary signal with clock synchronized system and transforming secondary signal between start-stop system and clock-synchronized system
US5432786A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 26, 1994 |
| Grant date | Jul 11, 1995 |
| Priority date | — |
| Expiry date | Jul 26, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L5/06
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A modulator receives a main signal synchronizing with a clock and a secondary signal having start and stop bits for each character. The modulator contains a unit for removing the start and stop bits from the secondary signal to generate a clock-synchronizing secondary signal. Then, the clock-synchronizing secondary signal and the main signal are modulated in parallel synchronized with a clock, and modulated signals are frequency division multiplexed. A demodulator receives a frequency division multiplexed modulated signal, and a clock-synchronizing main signal and a clock-synchronizing secondary signal are respectively regenerated by modulation and band separation. The demodulator contains a unit for inserting start and stop bits respectively before and after each character contained in the clock-synchronizing secondary signal to generate a secondary signal in a start-stop system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.