Method and apparatus for producing a difference signal between two signal frequencies, and for detection of modulation
US5732108A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1995 |
| Grant date | Mar 24, 1998 |
| Priority date | — |
| Expiry date | Aug 31, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D2200/007
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A frequency difference signal of a modulated signal (f.sub.1) and an unmodulated signal (f.sub.2) is produced maintaining the information of the frequency or phase modulation. According to the method, the time-related order of entry of the front edges of the pulses of the modulated and the unmodulated signal is controlled and the edge of the frequency difference signal in question at any moment is formed timewise at the same point as the edge of such modulated signal at which the time-related order of arrival of the modulating signal and the unmodulated signal has changed. Hereby, the frequency or phase shift of the modulated signal can be detected as an equivalent change in the frequency difference signal, and the modulation of the frequency difference signal is detected on the basis of the location of the pulse edge of the frequency difference signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.