Hi every one
I'm working on bandpass secound order filter and I have to have band pass between 23k and 53k using sallen key filters whaen I use the formola to dsign my high pass which should gave me 23k fc its working and I used the folwing calculation
R1 = mR, R2= R, C1=C , C2=nc FSF = 1 from the table
FSF * fc = 1/ 2pi RC squrt mn
m= 0.229 from the table
n= 3.3 from the table
I'm looking for LP for 53k
1*23k=1 / 2pi * (C=0.01u from th table) * (R which we need 2 find) * squrt 0.229*3.3
R = 1 / 2pi * (C=0.01u ) * (23k) * squrt 0.229*3.3 = 707 ohms
Since R = R2 so my R2 value is 707 ohms
R1 = R*m = 0.229 * 707 = 161.9 = 162 ohms
C1 = C which is 0.01u so the value of my C1 is 0.01u
C2 = n * C which is 3.3 * 0.01u = 33n
so my C2= 33n
and my LP filter which should gave me the fc=53k as
R1 = mR, R2= R, C1=C , C2=nc FSF = 1 from the table
FSF * fc = 1/ 2pi RC squrt mn
m= 0.229 from the table
n= 3.3 from the table
I'm looking for LP for 53k
1*53k=1 / 2pi * (C=0.01u from th table) * (R which we need 2 find) * squrt 0.229*3.3
R = 1 / 2pi * (C=0.01u ) * (53k) * squrt 0.229*3.3 = 345
Since R = R2 so my R2 value is 345 ohms
R1 = R*m = 0.229 * 345 = 79.005 = 80 ohms
C1 = C which is 0.01u so the value of my C1 is 0.01u
C2 = n * C which is 3.3 * 0.01u = 33n
so my C2= 33n
the main problem when I contact the output from my HP to the input of my LP filter the over all fc is not maching the fcs I looking for
can any one advice me how to conact the two filters together this can be using athered filter but my quation is do I need to change the holl calcultion and how?
many thanks
I'm working on bandpass secound order filter and I have to have band pass between 23k and 53k using sallen key filters whaen I use the formola to dsign my high pass which should gave me 23k fc its working and I used the folwing calculation
R1 = mR, R2= R, C1=C , C2=nc FSF = 1 from the table
FSF * fc = 1/ 2pi RC squrt mn
m= 0.229 from the table
n= 3.3 from the table
I'm looking for LP for 53k
1*23k=1 / 2pi * (C=0.01u from th table) * (R which we need 2 find) * squrt 0.229*3.3
R = 1 / 2pi * (C=0.01u ) * (23k) * squrt 0.229*3.3 = 707 ohms
Since R = R2 so my R2 value is 707 ohms
R1 = R*m = 0.229 * 707 = 161.9 = 162 ohms
C1 = C which is 0.01u so the value of my C1 is 0.01u
C2 = n * C which is 3.3 * 0.01u = 33n
so my C2= 33n
and my LP filter which should gave me the fc=53k as
R1 = mR, R2= R, C1=C , C2=nc FSF = 1 from the table
FSF * fc = 1/ 2pi RC squrt mn
m= 0.229 from the table
n= 3.3 from the table
I'm looking for LP for 53k
1*53k=1 / 2pi * (C=0.01u from th table) * (R which we need 2 find) * squrt 0.229*3.3
R = 1 / 2pi * (C=0.01u ) * (53k) * squrt 0.229*3.3 = 345
Since R = R2 so my R2 value is 345 ohms
R1 = R*m = 0.229 * 345 = 79.005 = 80 ohms
C1 = C which is 0.01u so the value of my C1 is 0.01u
C2 = n * C which is 3.3 * 0.01u = 33n
so my C2= 33n
the main problem when I contact the output from my HP to the input of my LP filter the over all fc is not maching the fcs I looking for
can any one advice me how to conact the two filters together this can be using athered filter but my quation is do I need to change the holl calcultion and how?
many thanks
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