| 摘要 |
A multiplexed filter with n channels comprises at least one amplifier G2 with n feedback capacitors C5 to C8 associated with the switches S5 to S8. A switch-controlled resistance R2 (C'r, K5, K6, K7, K8) is connected to its input. Switching signals phi i and phi p out of phase with each other are supplied to the switches K5 to K8 while the multiplexing signals phi 1 to phi 4 are applied to the switches S5 to S8. The signal phi 1 has a period T1 and the signals phi 2 to phi 4 have periods Ti=2(i-1)T1 where i=2 to 4. The period T1 is twice the period of phi i and phi p and the time intervals of all of T1 to T4 are equal to the period of phi i and phi p. This filter with n band pass ranges (n=4 in this example) can serve with advantage for the frequency analysis of an electrical signal delivered by a microphone. |
