1975-05-14
1977-01-04
Claffy, Kathleen H.
H04M 150
Patent
active
040015211
ABSTRACT:
A signal identification system, in which a signal of a specified frequency included in an analog signal indicated by an input pulse train converted from the analog signal is detected from the pulse train. The input pulse train is multiplied by two reference wave pulse trains having peak valves following the signal of the specified frequency but displaced by .pi./2 in phase from each other, respectively. The results of the multiplications are separately accumulated. The signal of the specified frequency is identified by utilizing a fact that the absolute value of at least one of the accumulated values exceeds a predetermined threshold value in the range of a permissible frequency deviation of the signal of the specified frequency and in the range of its permissible level fluctuation. The decision of the above fact may be performed when the accumulation is achieved at a certain number of times, which is predetermined in view of a permissible frequency deviation and a permissible level fluctuation of the signal of the specified frequency.
REFERENCES:
patent: 3652805 (1972-03-01), Wisner
patent: 3812432 (1974-05-01), Hanson
patent: 3863030 (1975-01-01), Mills
patent: 3882283 (1975-05-01), Proudfoot
Fukata Yasuo
Hatsumi Ryoichi
Adams Bruce L.
Burns Robert E.
Claffy Kathleen H.
Kokusai Denshin Denwa Kabushiki Kaisha
Lobato Emmanuel J.
LandOfFree
Signal identification system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Signal identification system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Signal identification system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-255978