I am stuck on a question regarding transfer functions. I have the answer and have attempted the question but am having trouble solving it.
Q: Given the transfer function of a digital filter is (5z-5)/z, compute the gain (in dB) of the digital filter at the cutoff frequency (10 rad/s)
The answer given is 14.65dB. (or a gain of 5.401)
I am unsure how to do this:
I see that the transfer function can be rewritten as 5(z-1)/z leading me to believe the gain would be 5 which is 13.98 dB, more than half a dB off.
What am I doing wrong here?