confusion regarding matlab command "fir1" - matlab

What is the meaning & signficance of using higlighted arguments like"DC-0" or "DC-1" as 3rd argument in fir1 command? Will my design remain valid if i skip these type of arguments?

'DC-0' specifies that the first band of a multiband filter is a stopband. 'DC-0' is the default when Wn has more than two elements.
'DC-1' specifies that the first band of a multiband filter is a passband.
for details see the matlab online help, click here

Related

How to use series in the GR-tensor package?

How can I use the series command for a specific quantity to find it up to a certain order of magnitude?
Is it possible to have an expanded series of a tensor in GR-tensor package?
Yes. You can apply series expansion to an object using the grmap() command.
The help for this function gives an example:
e.g. to do a taylor series expansion about r=a to second order
grmap(R(dn,dn,dn,dn), taylor, 'x',r=a,2);
See the help for grmap: ?grmap

Using if function in MATLAB Simulink

I have created the following block diagram on Matlab Simulink. It should give OUT1=1 OUT2=0 when INPUT>=0 and OUT1=0 OUT2=1 when INPUT<0. But it does not give the expected results. What is the reason for that. Any advice to make it work correctly would be appreciated.
The behaviour you are seeing can be explained by noting the following:
The output from the If Subsystem acts like an enable signal.
By default, the Output Ports of an If Action Subsystem are set to hold their values when the (sub)system is disabled.
This can be changed by going to the parameters dialog of the Output Port (within the If Action Subsystems) and changing the Output when disabled property to reset. You'll also want to change the default value to zero.
In many cases an IF is translated to a switch. You calculate cases and select the one which is intended. Here you could connect a constant [1 0] and a constant [0 1] to the first and third input and the sign block from your solution to the second input.
This if function block thing didn't work. So I come up with a different approach to get the result I wanted using the sign block. Solution is posted below. Thank you for everyone for trying to help.

Why does nothing work in my Matlab plot?

I am trying to plot with Matlab. In particular, I try with numerous online source but none of them work.
Here is my problem, I am trying to plot the expression: y=2*(x-1)/(x-4)Kb/L, and I am interested in the range of x between 0 and 1.
K=40;
b=20;
L=0.5;
x=linspace(0,1,1000);
y=2*(x-1)/(x-4)*K*b/L;
but it returns:
y=275.01
I know linspace isn't the proper way to plot. How can I plot this function? I want to keep the K,b,L declaration because I might change them latter.
y=2*(x-1)./(x-4)*K*b/L; you should use ./ replace /
Like hzy199411 said, you should use the "." operation.
I would suggest that you type "help ." at a MATLAB command prompt. MATLAB will respond with a large index of results but look for the section on "Arithmetic Operators".
You may also try the command "doc arith" but I think the "help ." is more helpful because at least in MATLAB 2013 it verbosely lists more "dot" operators.
In short several arithmetic operators prefixed with '.' ("Dot") are "Element-by-Element" operations and as such they operate on each index of the array/matrix.
For example if you had an array s=1:20 and you performed the operation s/s you would get ans = 1, where as if you did s./s you would get an array of 1's with the same length as 's'.
I guess that you are a new matlab user :). The program is in general ok, but you should think of some things. First,
linspace is not a plotting function. The function is useful though. With your syntax it creates a vector of length 1000 with range [0,1]. For plotting, type:
plot(x,y);
Linecolor and style can be set as
plot(x,y,'r-.');
For predefined colors (here 'r-.' means a red dotted line). There are also some additional properties that can be found be checking the online help of plot.
Also as the others say, if you want to operate on each element in the vector, use ./. The / is a matrix operator.

matlab zplane function: handles of vectors

I'm interested in understanding the variety of zeroes that a given function produces with the ultimate goal of identifying the what frequencies are passed in high/low pass filters. My idea is that finding the lowest value zero of a filter will identify the passband for a LPF specifically. I'm attempting to use the [hz,hp,ht] = zplane(z,p) function to do so.
The description for that function reads "returns vectors of handles to the zero lines, hz". Could someone help me with what a vector of a handle is and what I do with one to be able to find the various zeros?
For example, a simple 5-point running average filter:
runavh = (1/5) * ones(1,5);
using zplane(runavh) gives an acceptable pole/zero plot, but running the [hz,hp,ht] = zplane(z,p) function results in hz=175.1075. I don't know what this number represents and how to use it.
Many thanks.
Using the get command, you can find out things about the data.
For example, type G=get(hz) to get a list of properties of the zero lines. Then the XData is given by G.XData, i.e. X=G.XData.
Alternatively, you can only pull out the data you want
X=get(hz,'XData')
Hope that helps.

S-function documentation that "S-function level-1 supports vector inputs and outputs. DOES NOT support multiple input and output ports"

I read in S-function documentation that "S-function level-1 supports vector inputs and outputs. DOES NOT support multiple input and output ports".
Does the second sentence mean the input and output dimension must be the same?
I have been using S-function level-1 to do the following:
[a1, b1] = choose_cells(c, d);
where a1 and b1 are outputs, c and d are inputs. All the variables are having a single value, except d is an array with 6 values.
Referring to the image attached, we all know that in S-function block, the input dimension must be SAME as output dimension, else we will get error, in this case, the input dimension is 7 while the output dimension is 2, so I have to include the "Terminator" blocks in the diagram for it to work perfectly, otherwise, I will get an error.
My problem is, when the system gets bigger, the array d could contain hundreds of variables, using this method, it means I would have to add hundreds of "Terminator" blocks in order to get this work, this definitely does not sound practical.
Could you please suggest me a wise way to implement this?
http://imgur.com/ib6BTTp
http://imageshack.us/content_round.php?page=done&id=4tHclZ2klaGtl66S36zY2KfO5co
Updated: actually I have been trying to convert my level-1 S-function to level-2 but I got stuck at calling another sub function at function Output(block) trying to look for other threads but to no avail, do you mind to provide related links?
My output depends on a lot processing with the inputs, this is the reason I need to call the sub-function in order to calculate and then return output values, all the examples that I can see are calculating their outputs directly in "function Output(block)", in my case I thought it is not possible.
I then tried to use Interpreted Matlab Function block but failed due to the output dimension is NOT the same as input dimension, also it does not support the return of more than ONE output................
Level-1 s-function supports single input and single output port. These ports must be vectors. But there is no restriction on the length. Input and output can have different lengths. You can use selector block to select only relevant data. You do not need to use Bus in the output.
There is also no restriction on calling other sub-functions from Output. If your sub-function is not in the same file it must be in the path or in the current directory.
If your MATLAB code is compatible with MATLAB Function block, I recommend using that block. It is simpler to setup and use.