| 摘要 |
<p>The present invention relates to a sub-carrier filter and demodulator for a UWB communication receiver, comprising two mixers (10) each connected to receive multiple digitally modulated sub-carrier signals and respectively driven by two quadrature signals produced by a local oscillator (11) and to apply down-converted signals to respective low-pass filters before they are fed into a digital FSK demodulator circuit, wherein that said mixers (10) are J driven by triangular wave signals (LOI, LOQ) and comprise: - a first differential pair of transistors (24-25) having bipolar characteristics, for converting said sub-carrier signal (V<SUB>x</SUB>) into two currents (I<SUB>1</SUB>, I<SUB>2</SUB>), and - second and third pairs of transistors (16-18, 17-19) having bipolar characteristics, for respectively multiplying said currents (I<SUB>1</SUB>, 1<SUB>2</SUB>) with said triangular wave signals (LOI, LOQ) and applying them to said, low-pass filters (12). Application to UWBFM for reducing harmonics in mixers for downconversion. Mixers are implementable as Gilbert cells.</p> |
