Apparatus and method for tuning a filter
An apparatus and method for tuning a filter (11) with oscillator alignment for applications where the filter tuning signal (19, 27) is generated independently of the local oscillator tuning signal and the tuning range is large, for example such as terrestrial and cable TV broadcasting (40 to 860 MHz...
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| Format: | Patent |
| Sprache: | eng |
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| Zusammenfassung: | An apparatus and method for tuning a filter (11) with oscillator alignment for applications where the filter tuning signal (19, 27) is generated independently of the local oscillator tuning signal and the tuning range is large, for example such as terrestrial and cable TV broadcasting (40 to 860 MHz). The filter being adapted to a filter tuning modulation signal (25) having a first frequency (F1) and a second frequency (F2). Values of the output signal (28) are measured, a first value (S1) at the first frequency, and a second value (S2) at the second frequency, and a comparison signal (26) is generated in comparing the first value and the second value to adjust filter with the tuning control signal in response to the comparison signal, modulation signal and an approximate filter tuning signal to provide a desired signal at the output signal. |
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