Tone receiver for digital data communication systems
CA 1209666 A · Owner: International Business Machines Corporation · Inventors: Godard, Dominique
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A device for detecting the presence of an alarm tone of a given frequency within a received signal carrying digital data in addition to said tone. The receiver comprises an analog-to-digital converter the output of which is applied to a first recursive bandpass filter centered at the frequency of the alarm tone and the feedback loop of which includes a limiter. In addition, an input feedforward loop is provided for adding the output signal from the converter as multiplied by a coefficient ?, to the output signal from the limiter. The output signal from the adder is hard limited, then passed through a second bandpass filter. The energy of the signal obtained at the output of said second …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted August 12, 1986. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 12, 2003.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.