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OwnerMehmet Ipek, Phillippe Blaud +2inventors
InventorsMehmet Ipek, Phillippe Blaud, Martin Rieger, Heinrich Schemmann
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The upconverter mixer circuit comprises a Gilbert cell with an LC-resonator tuned to the output frequency of the upconverter mixer circuit, and an output buffer. In a preferred embodiment the output buffer comprises a differential amplifier being emitter degenerated with inductances for a low-pass characteristic. The LC-resonator of the Gilbert cell as well as the inductances of the output amplifier are integrated in an integrated circuit together with the other parts of the upconverter mixer circuit and provide a first selection within the integrated circuit for the subsequent stages, for example an intermediate frequency filter of a double conversion TV tuner. When the upconverter mixer circuit is operated with a strong DC-current and hard switching, which is necessary for achieving low noise, strong high frequency parasitic currents are also generated. These are mainly harmonics of the local oscillator frequency, which can be observed on the supply lines and input and output lines of the integrated circuit. The two stages of the upconverter mixer, the Gilbert cell followed by the output buffer, provide therefore a first intermediate filter to suppress parasitic currents within the upconverter mixer circuit. This enables to design a receiver with a large dynamic range and a high linearity, and having a low nois.
Upconverter mixer circuit for receiving a frequency band with a plurality of input channels, comprising a Gilbert cell and an output buffer, characterized in that the Gilbert cell comprises an LC-resonator tuned to the output frequency.
Double conversion tuner comprising an intermediate frequency filter and a downconverter, characterized in that it comprises further an upconverter mixer circuit according to one of the preceding claims, and that the bandpass characteristic of the LC-resonator and the lowpass characteristic of the output buffer of the upconverter mixer circuit are tuned to the intermediate frequency of the double conversion tuner.
Dependencies are inferred from the claim text.