Tuneable filter
AssigneeBAE SYSTEMS plc
InventorsNicholas John Easton, Christopher Ralph Pescod, Richard Peter Joyce
Life of this patent
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Abstract
A tuneable filter is provided in which a received signal in a first frequency range is translated to a signal of a higher frequency range by a switchable frequency oscillator signal, filtered in a narrow band filter and then down-converted, possibly to the first frequency range. The switchable frequency oscillator signals are generated by a synthesizer which operates by mixing oscillator signals of different frequencies, selected by fast-switching microwave switches, in order to generate the required range of oscillator signal frequencies.
Claims14
1-15. (canceled)
A tuneable filter, comprising:
- an input for receiving a signal in a first frequency range;
- a first mixer to combine a first oscillator signal with a signal received at said input to thereby translate the received signal to a signal in a second frequency range;
- a filter to pass signals of frequencies within a predetermined frequency band within said second frequency range;
- and
- a second mixer to combine a second oscillator signal with a signal passed by said filter to translate said filtered signal to a signal in a third frequency range, different than said second frequency range.
A signal processing apparatus, comprising:
- an input for receiving signals in a first frequency range;
- a tuneable filter to select switchably the signals of a predetermined bandwidth from signals received at said input, the filter including:
- an input for receiving a signal in a first frequency range,
- a first mixer to combine a first oscillator signal with a signal received at said input to thereby translate the received signal to a signal in a second frequency range,
- a filter to pass signals of frequencies within a predetermined frequency band within said second frequency range, and
- a second mixer to combine a second oscillator signal with a signal passed by said filter to translate said filtered signal to a signal in a third frequency range, different than said second frequency range;
- a first frequency translation arrangement for translating signals selected by said tuneable filter into signals of a frequency for processing;
- and
- a processing arrangement to process the selected signals.
Dependencies are inferred from the claim text.