Channel selecting apparatus for simultaneous use with both phase-continuous modulation signals and digital modulation signals
US5483686A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 2, 1993 |
| Grant date | Jan 9, 1996 |
| Priority date | — |
| Expiry date | Nov 2, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03J1/005
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A channel selecting apparatus simultaneously selects both the modulation signals, which are simultaneously received at different channels where modulation signals having a continuous phase and digital modulation signals having a discontinuous phase are located. As both the modulation signals are propagated on the same transmission path or approximately the same inclination of transmission path, modulation signals existing on different channel frequencies suffer approximately similar frequency shift from the transmission path before being inputted to the channel selecting apparatus. Therefore, the frequency of the digitally modulated IF signal can be controlled in accordance with the frequency shift information related to an IF signal having a continuous phase and the frequency of the digitally modulated IF signal may be focused into the comparatively narrow frequency range around the synchronous pull-in frequency of the digital demodulating circuit and the modulation signal having a continuous phase may be focused into the comparatively narrow frequency range around the optimum input frequency of the demodulation circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.