FILTER CIRCUIT ARRANGEMENT
First Claim
1. A filter circuit arrangement for filtering a radio-frequency signal having a frequency, comprising:
- a first tunable filter having an attenuation characteristic;
a phase regulation loop that holds said first tunable filter to a transmission phase that is constant relative to the frequency of the radio-frequency signal;
a second tunable filter connected in parallel with the first tunable filter in the phase regulation loop, said second tunable filter having an attenuation characteristic that is different from the attenuation characteristic of the first tunable filter; and
said first tunable filter and said second tunable filter being connected within said phase regulation loop to cause a capture range of the filter circuit arrangement, in which tuning of the phase regulation loop to the radio-frequency signal is possible, to be dominated by the attenuation characteristic of the second tunable filter, and to cause a transmission behavior of the filter circuit arrangement to be dominated by the attenuation characteristic of the first tunable filter when the phase regulation loop is tuned to said radio-frequency signal.
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Accused Products
Abstract
A filter circuit arrangement for filtering of a radio-frequency signal has a first tunable filter and a phase regulation loop in order to hold the first tunable filter to a transmission phase constant relative to the frequency of the radio-frequency signal. The filter circuit arrangement has a second tunable filter arranged parallel to the first tunable filter in the phase regulation loop. The first tunable filter and the second tunable filter exhibit different attenuation characteristics and are fashioned and connected within the phase regulation loop so that: a capture range of the filter circuit arrangement, in which a tuning of the phase regulation loop to a radio-frequency signal to be filtered is possible is dominated by the attenuation characteristic of the second tunable filter, and so that the transmission behavior of the filter circuit arrangement in operation is dominated by the attenuation characteristic of the first tunable filter, given a tuned phase regulation loop. A circuit arrangement for generation of a local oscillator signal has an oscillation generator and a filter circuit arrangement as described above arranged downstream of the oscillation generator.
34 Citations
16 Claims
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1. A filter circuit arrangement for filtering a radio-frequency signal having a frequency, comprising:
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a first tunable filter having an attenuation characteristic; a phase regulation loop that holds said first tunable filter to a transmission phase that is constant relative to the frequency of the radio-frequency signal; a second tunable filter connected in parallel with the first tunable filter in the phase regulation loop, said second tunable filter having an attenuation characteristic that is different from the attenuation characteristic of the first tunable filter; and said first tunable filter and said second tunable filter being connected within said phase regulation loop to cause a capture range of the filter circuit arrangement, in which tuning of the phase regulation loop to the radio-frequency signal is possible, to be dominated by the attenuation characteristic of the second tunable filter, and to cause a transmission behavior of the filter circuit arrangement to be dominated by the attenuation characteristic of the first tunable filter when the phase regulation loop is tuned to said radio-frequency signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A circuit arrangement for generating a local oscillator signal comprising:
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an oscillator generator that generates a radio-frequency signal; and a filter circuit arrangement that filters said radio-frequency signal, said filter circuit arrangement comprising a first tunable filter having an attenuation characteristic, a phase regulation loop that holds said first tunable filter to a transmission phase that is constant relative to the frequency of the radio-frequency signal, a second tunable filter connected in parallel with the first tunable filter in the phase regulation loop, said second tunable filter having an attenuation characteristic that is different from the attenuation characteristic of the first tunable filter, and said first tunable filter and said second tunable filter being connected within said phase regulation loop to cause a capture range of the filter circuit arrangement, in which tuning of the phase regulation loop to the radio-frequency signal is possible, to be dominated by the attenuation characteristic of the second tunable filter, and to cause a transmission behavior of the filter circuit arrangement to be dominated by the attenuation characteristic of the first tunable filter when the phase regulation loop is tuned to said radio-frequency signal, and, said filter circuit arrangement having an output connected to said first and second tunable filters at which a local oscillator signal is emitted that is generated by said first and second tunable filters from said radio-frequency signal.
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Specification