This filter lets digital frequencies within its passband to pass though with the help of two monoflops. A bandpass filter has two definite
cut-off frequencies: fmax and fmin. The bandwidth b is fmax-fmin while the center frequency is fmin+b/2 or fmax-b/2.
The upper cut-off frequency fmax is determined by the pulse length (t1) of the monoflop M1.
t 1 = Tmin ( b/ fmax)
The lower cut-off frequency (fmin) comes from the sum of the pulse
length of the monoflop 1 and
fmin = 1/ (t1+t2)
The pulse length (t) is determined by RC components P2/C2 and P1/C3 and can be found mathematically by:
The value of P can be chosen from 5 ohm up to 50K.
t = 0.32*C*(P+700)
Parts Placement Layout
Electronic Circuits volume 1.0 - Circuit Nr. 14
The complete data of the electronic circuit described above can be found in the following book and is available from Amazon.com.
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