Electric direct current telegraphy transmitter
CA 1099368 A · Owner: N.V. Philips Gloeilampenfabrieken · Inventors: Rademaker, Gerrit
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
PHN 8782, 3.3.78, ABSTRACT:, An electronic transmitter for direct current telegraphy by means of polar line currents comprises a switching circuit for selectively connecting one of the two poles of a telegraphy battery through a unipolar constant current source to a telegraph line and an, output filter having a capacitor in parallel with the telegraph line. The higher frequencies in the telegraphy signals are sufficiently suppressed to keep the noise level in adjacent telephone lines below a prescribed value because the output filter also comprises two complementary branches in parallel with the telegraph line at least one of the two branches supplying in response, to a polarity transition …
Read the whole patent
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 April 14, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 14, 1998.
- 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.