SignalManager

The SignalManager comes with some basic parameters.

field	description
fs	sampling frequency
num_channels	number of channels
channel_names	name for each channel
data	the signal in the structure of (epoch x channel x signal)
t	time vector
epochs	number of epochs
tags	position of tags in signal
spectrum	matrix of spectrum
spectrum_freqs	vector of frequencies
phase	matrix of phase
history	a list of all the steps taken

When initializing the object there are two options.

Generator

A dictionary of the structure

data = {
      'fs': # float,
      'num_channels': # integer,
      'channel_names': # list of strings,
      'epochs': # integer,
      't': # time array,
      'tags': # list,
      'data': # Signal Matrix
  }

saffy.SignalManager(generator=data)

Filename

The name of the file generated by Svarog. 3 files eg. data.raw, data.xml, data.tag

saffy.SignalManager(filename='data')

---

set_tags_from_channel(self, channel_name)

Uses a channel as the tag indicator. Normalizes the value to 1 through divided by the maximum value. Sets threshold at 0.9. Sets tag at beginnings of resultant clusters.

Params

• channel_name: the string name of the channel to set tags from.

set_epochs_from_tags(self, low, high)

Uses the tag list to cut the data into epochs. The low and high tell us where to cut based on the tags. They are in seconds. For example if you want to cut between 2 seconds before and 3 after the tag you would write sig.set_epochs_from_tags(-2, 3).

Params

• low: In seconds. Starting time of the epoch relative to the tag. The tag is 0 seconds.
• high: In seconds. Ending time of the epoch relative to the tag. The tag is 0 seconds.

remove_channels(self, channel_names)

Removes the specified channels from the data.

Params

• channel_names: list of strings

extract_channels(self, channel_names)

Removes all channels except for those provided in the channel_names parameter.

Params

• channel_names: list of strings

extract_time_range(self, low, high)

Cuts data to the provided low and high arguments.

Params

• low: starting point of new signal in seconds.
• high: end point of new signal in seconds.

copy(self, name="")

Creates a independent copy of the SignalManager object.

Params

• name: a documenting value to keep track why we are coping the signal.

call(self, func)

Used to run single custom functions on the data. Allows consistency when building analysis piplines.

Params

• func: a function that takes only self as the parameter.

Example

You should do this:

def custom_function(self):
    print(self.data)

sig.call(custom_function)

instead of this:

def custom_function(sig):
    print(sig.data)

custom_function(sig)

register_plugin(cls, plugin)

Use this to add a custom plugin to be used with the SignalManager

Params

• plugin: An instance of the PluginManager class.

Example

Create a custom plugin.

class CustomPlugin(saffy.PluginManager):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.custom = {
            'param': 'some value'
        }

    def custom_function(self):
        # do something
        pass

Then you can regiser it and use the custom_function.

saffy.SignalManager.register_plugin(CustomPlugin)

History

All the operations on the signal are stored in the history parameter. It allows to keep track of the changes that have been made to the signal.

Chaining

Each method returns self, so chaining of functions is possible. For example setting tags could be done this way.

sig = SignalManager(filename='path/to/file')\
    .extract_channels(['C3', 'C4', 'trig'])\
    .set_tags_from_channel('trig')\
    .remove_channel('trig')