LTPDA Toolbox™ contents Select and find data from an AO   IFO/Temperature Example - Pre-processing

Split and join AOs

You can split the data inside an AO to produce one or more output AOs. The ao/split method splits an AO by samples, times (if the AO contains time series data), frequencies (if the AO contains frequency data), intervals, or a number of pieces. We can control this as usual by defining our parameters. This is a very flexible method, so take your time and check all its possibilities.

Split by times

Let us create a new time series AO for these examples. 

    pl = plist('name', 'None', 'nsecs', 10, 'fs', 1000, 'tsfcn', 'sin(2*pi*7.433*t) + randn(size(t))', 'yunits', 'V');
    a = ao(pl);

For splitting in time we need to define a time vector for the parameter list and pass it to ao/split: 

    pl_time = plist('times', [2 3]);
    a_time  = split(a, pl_time);
    iplot(a, a_time)
split

Split by frequencies

For this we need a frequency data AO. One easy way to get this is by computing the power spectrum using ao/psd. 

    axx = a.psd;

Again we need a vector for the parameter list and pass it to ao/split: 

    pl_freq  = plist('frequencies', [10 100]);
    axx_freq = split(axx, pl_freq);
    iplot(axx, axx_freq)
split

Split by intervals

We can also split the AO by passing a time interval to the ao/split method: 

    pl_interv = plist('start_time', 4, 'end_time', 6);
    a_interv = split(a, pl_interv);
    iplot(a, a_interv)
split_interv

Split by samples

This type of splitting method we can use on any type of data. Let us use the frequency type, axx.

Again we need a vector for the parameter list and pass it to ao/split, only that this time we will split our AO in to two parts. 

    pl_samp = plist('samples', [50 100 101 300]);
    [axx_samp1 axx_samp2] = split(axx, pl_samp)
    iplot(axx, axx_samp1, axx_samp2)
split_samp

Although in this example the two resulting AOs are contiguous, they need not to be.

Join AOs

We can join our two AOs back together using ao/join: 

    axx_join = join(axx_samp1, axx_samp2);
    iplot(axx, axx_join)
split_join

If we look at the history for axx_join (by entering axx_join.viewHistory), we will see the following:

Split/join history

Since the two AOs that are output from the 'split by samples' stage are independent, the history tree reflects this, showing two independent branches leading to the join step.


Select and find data from an AO  Select and find data from an AO   IFO/Temperature Example - Pre-processing IFO/Temperature Example - Pre-processing

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