Patents by Inventor Tak K Chan

Tak K Chan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Image reject mixer
    Patent number: 6308058
    Abstract: Circuit 200 comprises an input amplifier stage 290, phase-splitters 292, 293 and mixer cores 294, 295. An input signal is applied to terminal 220, a local oscillator signal applied to terminals 230, 231 and a 90° shifted local oscillator signal is applied to terminals 232, 233. The In-phase differential signal is output at terminals 240, 241 and the quadrature signal is output at terminals 240, 233. Phase-splitters 292, 293 comprise base-coupled transistors 202, 203, 205, 206 which are biased by a potential applied to terminal 262. As these phase-splitters are driven by input amplifier stage 290, which acts as a current source, the arrangement has very good noise properties. Degeneration inductor 280 reduces the noise figure of the circuit further because it is a noiseless component.
    Type: Grant
    Filed: January 7, 1998
    Date of Patent: October 23, 2001
    Assignee: Mitel Semiconductor Limited
    Inventors: Viatcheslav I Souetinov, Tak K Chan