| 摘要 |
A notch filter circuit (12) is provided including a first stage circuit (50) and a second stage circuit (52). The first stage circuit (50) sums a filter input signal (56) with a filter output signal (67) to form a summation signal. The second stage circuit (52) includes a first tee network (60) and a second tee network (62). The first tee network (60) low-pass filters the filter input signal to form a first tee output signal. The second tee network (62) high-pass filters the summation signal to form a second tee output signal. A first multiplying digital-to-analog converter (64) is electrically coupled to the first tee network (60) and the second tee network (62). The first converter (64) modifies the gain of the second tee network (62) in response to a gain signal to form a corrected second tee network signal, thereby adjusting a notch filter frequency (Fig. 2).
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