Tree mixer with interstage filter
CA 2244302 A1 · Owner: Bell-Northern Research Ltd. · Inventors: Nisbet, John Jackson; Kung, William
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A conventional tree mixer has a gain stage formed of a differential pair of transistors and a mixing stage formed of two differential pairs of transistors. To prevent image noise from passing from the gain stage to the mixing stage or to prevent local oscillator frequencies from being coupled from the mixing stage to the gain stage due to parasitic capacitance an interstage filter is provided. In one configuration the filter is a notch filter tuned to block either the image frequency or the local oscillator frequency.
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
- Filed July 28, 1998. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended July 28, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 28, 2020.
- 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.