how to set the center frequency of LM567???

[cool]

I have followed the data sheet of LM567 to build up a circuit to encode 10kHz input singal, but it doesn't work........ :cry:

I used R1=2k, C1=47nF, 0.1uF and 0.01uF at pin 1 and pin 2.

It seems no center frequency appeard, all input signals with different frequencies have the similar value of output voltage..........

What can I do??? Did I make any mistake???
Please help me.... :wink:

 

[Russlk]

The bandwidth is way too wide. Try 2000 uF at pin 2.

For 10% bandwidth, 0.1 = 1070*sqrt(vin/Fo/C2)

(9.3*10^-5)^2 = vin/Fo/C2 Let vin =0.2 & Fo = 10^4 then

87*10^-10 = .2/10^4/C2

C2 = .2*10^-4/.87*10^-8 = .23 *10^4 uF

 

[cool]

o, thanks~
but what is Vi?
is it the supply voltage of the circuit of the encoder?? :roll:

 

[Russlk]

Vin is the amplitude of the signal input to the 567. I don't know why it affects the bandwidth.