sxb416
Junior Member level 1
How to use the biquadradic swtiched cap filter structure to design a
lowpass filter. H(z) = 0.147*(Z^2-1.944Z +1)/(Z^2-1.955Z+0.9878)
the f0=945, Q=14.8, dc=0,fn=1200?
I have use the equation to get the a,b,c,d,e,g,k cap value.
then use SWITHCAP to scaling it .
When use the final value to simulation in SWITHCAP software ,the result is good,
but when I replace the switch and amp to nmos and real amp,the result is bad,
why,
my amp is dc gain 80db, UBG 7meg,SR 10u/us,supply is 3.3
lowpass filter. H(z) = 0.147*(Z^2-1.944Z +1)/(Z^2-1.955Z+0.9878)
the f0=945, Q=14.8, dc=0,fn=1200?
I have use the equation to get the a,b,c,d,e,g,k cap value.
then use SWITHCAP to scaling it .
When use the final value to simulation in SWITHCAP software ,the result is good,
but when I replace the switch and amp to nmos and real amp,the result is bad,
why,
my amp is dc gain 80db, UBG 7meg,SR 10u/us,supply is 3.3