10006039
FIGURE 15. State Variable Active Filter
From Equation 12,
From the above calculated values, the midband gain is
H0 = R3/R2 = 100 (40 dB). The nearest 5% standard values
have been added to Figure 15.
PULSE GENERATORS AND OSCILLATORS
A pulse generator is shown in Figure 16. Two diodes have
been used to separate the charge and discharge paths to ca-
pacitor C.
where for all three filters,
(11)
(12)
A design example for a bandpass filter is shown below:
Assume the system design requires a bandpass filter with f O
= 1 kHz and Q = 50. What needs to be calculated are capacitor
and resistor values.
First choose convenient values for C1, R1 and R2:
C1 = 1200 pF
2R2 = R1 = 30 kΩ
Then from Equation 11,
10006081
FIGURE 16. Pulse Generator
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