How do i implement a gain of 10 inside my filter MAtlab?

In MAtlab i have a filter with transfer functions coefficients A and B and then i use the 'filter' funtion syntax to implement the filter in our input signal.

Now i also need to implement a gain of 10 or 20 inside my filter so that i get an amplified signal.How do i do that?

ANy help will be appreciated

Answer 1

[Jan]

See this:

t      = 1:30;
x      = rand(1, 30);          % Some test data
[b, a] = butter(3, 0.8);       % A Butterworth filter
x1     = filter(b, a, x) * 4;  % Filter and amplify
x2     = filter(b * 4, a, x);  % Amplify internally

plot(t, x1, 'ro', t, x2, 'c-')
max(abs(x1-x2))   % 0.0, but some rounding error can be expected

[sachin narain]

Thanks for the response so i should do b*4 (that is the denominator *4) right??

[Jan]

See https://www.mathworks.com/help/matlab/ref/filter.html#bt_vs4t-1-b ( doc filter -> b):

b — Numerator coefficients of rational transfer function