Filter circuit

A circuit 10 for filtering signals which outputs a plurality of signals at a plurality of frequencies, each of the signals being attenuated by an amount determined by the frequency of the signal. The circuit attenuates signals output at a first frequency by an amount which is low relative to the att...

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Bibliographische Detailangaben
Hauptverfasser:	JOUNI KRISTIAN KAUKOVUORI, JONNE JUHANI RIEKKI, RISTO HEIKKI SAKARI KAUNISTO, PETRI TAPANI ELORANTA, JARI JOHANNES HEIKKINEN
Format:	Patent
Sprache:	eng
Schlagworte:	BASIC ELECTRONIC CIRCUITRY ELECTRIC COMMUNICATION TECHNIQUE ELECTRICITY IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS RESONATORS TRANSMISSION
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Beschreibung
Zusammenfassung:	A circuit 10 for filtering signals which outputs a plurality of signals at a plurality of frequencies, each of the signals being attenuated by an amount determined by the frequency of the signal. The circuit attenuates signals output at a first frequency by an amount which is low relative to the attenuation of signals output at frequencies other than the first frequency. The circuit further attenuates signals output at a second frequency by an amount which is high relative to the attenuation of signals output at frequencies other than the second frequency. Responsive to a change in the control signal 27, the circuit changes the first and second frequencies while maintaining a fixed ratio between the first and second frequencies. The circuit may comprise a parallel resonant circuit 20 in series with a series resonant circuit 22 and may share the same variable capacitor 26. The second frequency may be a harmonic of the first frequency and the fixed ratio may be two or three. The filter circuit may be used in a direct conversion receiving or transmitting chain.