发明授权
US5339333A FSK demodulator using signal transitions 失效
FSK解调器使用信号转换

FSK demodulator using signal transitions
摘要:
An FSK demodulator is provided comprising means for receiving and digitizing an FSK signal (such as a signal comprising two frequencies f1 and f2 in which first and second logic states are represented by first and second periods of different durations). First, second, third and fourth consecutive transitions of the signal are identified and the times of said transitions are identified. A first period between the first and third transitions is calculated, as is a second period between the second and fourth transitions. A change of frequency in the signal is indicated when the first and second periods lie on opposite sides of a first threshold period (.tau.) and no change of frequency is indicated when the first and second periods lie on the same side of the threshold period (.tau.). In a further aspect of the invention, a transition is rejected as illegal when two consecutive transitions occur within a predetermined period of time.
公开/授权文献
信息查询
0/0