| 摘要 |
<p>The circuit has an operational amplifier (10) with a feedback capacitor between its output (13) and its inverting input (11), its non-inverting input (12) being coupled to earth. The amplifier inverting input (11) is coupled via a switch (S13) to a circuit node (19) connected to earth via a capacitor (16) and via a second switch (S14) to a second circuit node (20). This is coupled via respective switches (S15,S16) to the amplifier inverting input (11) and its output (13) and by a further switch (S23) to the circuit input (17). The first and last of these switches (S13,S23) are closed simultaneously, with the remaining switches (S14,S15,S16) closed one after the other.. The filter circuit can be formed as an integrated MOS circuit and exhibits good stability and low spurious noise.</p> |
