I have designed a band-pass filter with filter order 8 , window and fc1=42Mhz and fc2=43Mhz.
I'm getting the following results when I compare input and output using scope which i have attached in below snapshot.
In the waveform, the yellow wave is the input and the blue wave is the output. When input is 42Mhz, the amplitude of both input and output is same.
When the input is 60Mhz the amplitude of output is less than the amplitude of input. I have attached the snapshot of both the simulation result below. Is the filter working fine or not?
I'm able to see the wave for both the cases but only amplitude is getting reduced when the input is moving away from cutoff frequency. I have also attached the filter specification which I have given in FDA tool.
P,lease look into this and let me know if the filter is working fine or not.
The filter is doing what it is designed to do. At 60MHz the curve is showing about a 3dB to 4dB attenuation. 3dB will bring the amplitude down to 1/SQRT(2) of the input amplitude. The simulation is showing about this much difference between input and output at 60MHz.