root/experimental/AWG/trunk/AWG/sources.py @ 5045

#!/usr/bin/env/python

'''
This module contains signal sources that can be called by AWG.py.  

To add a custom source, you must make changes in two places:

1.  Add the name that you want to appear in the AWG graphical user 
    interface to the self.available_sources dictionary as dictionary keys.  
    The corresponding values in the dictionay indicate which function is 
    called when each source is selected.

2.  Add your function that generates your custom signal anywhere below the 
    comment line "#source functions are defined below:".  Your function 
    should fit the same general format as the existing functions:

    def my_function(self):
        #define your signal here
        return your_signal
'''

import math
import random

class sources:
    def __init__(self,parent):
        self.parent = parent
        self.available_sources = {'file': 'read_file()', 
                                  'sine': 'gen_sine()', 
                                  'cosine': 'gen_cosine()',
                                  'random': 'gen_random_data()',
                                  'zeros': 'gen_zeros()',
                                  'ones': 'gen_ones()'}


    def get_sources_list(self):
        return self.available_sources


    def gen_signal(self):
        eval_string = "self." + self.available_sources[self.parent.signal_type]
        return eval(eval_string)  # return the signal generated by 
                                  # the corresponding method


#------------------------------------------------------------------------------
# source functions are defined below:

    def read_file(self):
        '''Reads data from a file and returns the items in the file as a list.
           Parent class must have a variable "file_name" and a variable 
           "delimiter".''' 
        try:
            my_file = open(self.parent.file_name, 'r')
        except IOError:
            print "no file named " + self.parent.file_name
            return []  # return an empty packet

        data_from_file = my_file.read()   # read the file as a big string
        my_file.close()   # done reading the file.  
                          # process the string from now on

        data_from_file.strip('\n')  # \n's will not be tollerated
        data_from_file.strip('[')   # ['s will not be tollerated
        data_from_file.strip(']')   # ]'s will not be tollerated

        # break the string into a list
        data_from_file = data_from_file.split(self.parent.delimiter)  

        return data_from_file


    def gen_sine(self):
        '''Generates a sinusoid and returns it as a list.  Parent must have 
           a variable "signal_len" that corresponds to the number of elements 
           in the list.  Parent must have a variable "frequency" that 
           corresponds to frequency in cycles per packet.'''
        count = 0
        sine = []
        while count < self.parent.signal_len:
            sine.append(math.sin(self.parent.frequency*2*math.pi*count/self.parent.signal_len))
            count = count + 1

        return sine


    def gen_cosine(self):
        '''Generates a cosine and returns it as a list.  Parent must have 
           a variable "signal_len" that corresponds to the number of elements 
           in the list.  Parent must have a variable "frequency" 
           that corresponds to frequency in cycles per packet.'''

        count = 0
        cosine = []
        while count < self.parent.signal_len:
            cosine.append(math.cos(self.parent.frequency*2*math.pi*count/self.parent.signal_len))
            count = count + 1

        return cosine


    def gen_random_data(self):
        '''the rand_type variable defines which function call to use 
           in the random module'''
        data = []

        # lower() makes the comparison case insensitive
        tmp_rand_type = self.parent.rand_type.lower()  
        if tmp_rand_type == 'random':
            count = 0
            while count < self.parent.signal_len:
                data.append(random.random())
                count = count + 1
        elif tmp_rand_type == 'uniform':
            count = 0
            while count < self.parent.signal_len:
                data.append(random.uniform())
                count = count + 1
        else:
            print "random methods other than random and uniform are not supported in sources.random_data"

        return data
                

    def gen_zeros(self):
        '''returns a list of zeros'''
        data = []
        for n in range(self.parent.signal_len):
            data.append(0)
        return data

    def gen_ones(self):
        '''returns a list of ones'''
        data = []
        for n in range(self.parent.signal_len):
            data.append(1)
        return data