Class: SPCore::CombFilter

Inherits:
Object
  • Object
show all
Includes:
Hashmake::HashMakeable
Defined in:
lib/spcore/generation/comb_filter.rb

Constant Summary collapse

FEED_FORWARD = 
:feedForward
FEED_BACK = 
:feedBack
TYPES = 
[ FEED_FORWARD, FEED_BACK ]
ARG_SPECS = 
{
  :type => arg_spec(:reqd => true, :type => Symbol, :validator => ->(a){ TYPES.include?(a)}),
  :frequency => arg_spec(:reqd => true, :type => Numeric, :validator => ->(a){ a > 0}),
  :alpha => arg_spec(:reqd => true, :type => Float, :validator => ->(a){ a.between?(0.0,1.0) })
}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(args) ⇒ CombFilter

Returns a new instance of CombFilter.



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# File 'lib/spcore/generation/comb_filter.rb', line 18

def initialize args
  hash_make args, CombFilter::ARG_SPECS
  calculate_params
end

Instance Attribute Details

#alpha ⇒ Object

Returns the value of attribute alpha.



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# File 'lib/spcore/generation/comb_filter.rb', line 16

def alpha
  @alpha
end

#frequency ⇒ Object

Returns the value of attribute frequency.



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# File 'lib/spcore/generation/comb_filter.rb', line 16

def frequency
  @frequency
end

#type ⇒ Object

Returns the value of attribute type.



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# File 'lib/spcore/generation/comb_filter.rb', line 16

def type
  @type
end

Instance Method Details

#frequency_response(sample_rate, sample_count) ⇒ Object 



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# File 'lib/spcore/generation/comb_filter.rb', line 49

def frequency_response sample_rate, sample_count
  output = []
  sample_period = 1.0 / sample_rate
  sample_count.times do |n|
    x = sample_period * n
    output.push frequency_response_at(x)
  end
  return output
end

#frequency_response_at(x) ⇒ Object 



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# File 'lib/spcore/generation/comb_filter.rb', line 39

def frequency_response_at x
  output = 0
  if @type == FEED_FORWARD
    output = Math.sqrt((1.0 + @alpha**2) + 2.0 * @alpha * Math.cos(@k * x))
  elsif @type == FEED_BACK
    output = 1.0 / Math.sqrt((1.0 + alpha**2) - 2.0 * @alpha * Math.cos(@k * x))
  end
  return output
end