Frequency response from a transfer function?

I have the following transfer function:

And I want to plot its frequency response but I am not sure how to do it. I hope someone can help

[Saurabh]

clc;

clear all;

num=[100];

den=[1,15,100];

impulse(num,den);

grid;

Answer 1

[Star Strider]

I assume you intend a bode or bodeplot plot —

s = tf('s');
G = exp(-s)/(2*s+1)

G =
 
                 1
  exp(-1*s) * -------
              2 s + 1
 
Continuous-time transfer function.

figure
bodeplot(G)
grid

See the documentation I linked to, as well as the tf function, for details.

.

Answer 2

[Dyuman Joshi]

Use freqs. Note - Requires the Signal Processing Toolbox.

Refer to the documentation page linked above for more info.

help freqs

 FREQS Laplace-transform (s-domain) frequency response.
    H = FREQS(B,A,W) returns the complex frequency response vector H
    of the filter B/A:
                         nb-1         nb-2
             B(s)   b(1)s     +  b(2)s     + ... +  b(nb)
      H(s) = ---- = -------------------------------------
                         na-1         na-2
             A(s)   a(1)s     +  a(2)s     + ... +  a(na)
 
    given the numerator and denominator coefficients in vectors B and A.
    The frequency response is evaluated at the points specified in
    vector W (in rad/s).  The magnitude and phase can be graphed by
    calling FREQS(B,A,W) with no output arguments.
 
    [H,W] = FREQS(B,A) automatically picks a set of 200 frequencies W on
    which the frequency response is computed.  FREQS(B,A,N) picks N
    frequencies.
 
    % Example 1:
    %   Find and graph the frequency response of the transfer function
    %   given by
    %   H(s) = ( 0.2*s^2 + 0.3*s + 1 )/( s^2 + 0.4s + 1 )
 
    a = [1 0.4 1];      % Numerator coefficients
    b = [0.2 0.3 1];    % Denominator coefficients
    w = logspace(-1,1); % Frequency vector
    freqs(b,a,w)
 
    % Example 2:
    %   Design a fifth-order analog lowpass Bessel filter with an
    %   approximate constant group delay up to 10,000 rad/s and plot
    %   the frequency response of the filter using freqs.
 
    [b,a] = besself(5,10000);   % Bessel analog filter design
    freqs(b,a)                  % Plot frequency response
 
    See also LOGSPACE, POLYVAL, INVFREQS, and FREQZ.

    Documentation for freqs
       doc freqs

[Ali Almakhmari]

I think this is exactly what I am looking for. But I am not sure if I can use this command with e^-s in my numerator of the transfer function.