Method and device for coherent demodulation of a digitally modulated carrier
Номер патента: CA1227546A
Опубликовано: 29-09-1987
Автор(ы): Jacques Veillard
Принадлежит: Telediffusion de France ets Public de Diffusion
Опубликовано: 29-09-1987
Автор(ы): Jacques Veillard
Принадлежит: Telediffusion de France ets Public de Diffusion
Реферат: ABSTRACT Method and device for coherent demodulation of a digit-ally modulated carrier A digitally modulated carrier modulated by phase shift keying or frequency shift keying with phase conti-nuity, transmitted as useful bursts distributed at equal time intervals with phase continuity from each burst to the next burst. The carrier frequency is recovered by squaring the carrier for obtaining a spectrum and se-lecting the carrier frequency within said spectrum. Bursts at an acquisition frequency having the same frequency as the carrier, having a time duration longer than the time duration of the useful bursts and having characteristic features which are particular to said acquisition burst, are sent at times which are separated by time periods having a duration which is longer than the repetition period of the useful bursts by at least an order of magnitude. The acquisition bursts are re-ceived along with the useful bursts and squared to pro-vide an acquisition spectrum. A frequency which is double of the carrier frequency is selected within the acquisition period by identifying the characteristic feature of the acquisition bursts.
Method and apparatus for using the video blanking period for the maintenance of a modem that is used for wireless transmission of video
Номер патента: EP1969841A2. Автор: Meir Feder,Zvi Reznic,Shay Freundlich,Nathan Elnathan. Владелец: AMIMON LTD. Дата публикации: 2008-09-17.