Module: Radio::Utils

Included in:
PSK31::Rx, Rig
Defined in:
lib/radio/utils/misc.rb,
lib/radio/utils/firpm.rb,
lib/radio/utils/window.rb

Defined Under Namespace

Classes: FirPM

Constant Summary collapse

FIRPM_CACHE_VERSION = 
1
FIRPM_CACHE_FILENAME = 
File.expand_path '~/.radio_firpm_cache'
@@firpm_cache = 
{}
@@firpm_mtime = 
nil

Class Method Summary collapse

Class Method Details

.firpm(options) ⇒ Object 



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# File 'lib/radio/utils/firpm.rb', line 31

def firpm options
  out = nil
  File.open(FIRPM_CACHE_FILENAME, File::CREAT|File::RDWR) do |f|
    f.flock(File::LOCK_EX)
    if f.mtime != @@firpm_mtime
      @@firpm_cache = YAML::load(f)
      unless @@firpm_cache and @@firpm_cache[:version] == FIRPM_CACHE_VERSION
        @@firpm_cache = {version:FIRPM_CACHE_VERSION}
      end
      f.seek 0
      @@firpm_mtime = f.mtime
    end
    firpm = FirPM.new(options)
    out = @@firpm_cache[firpm.options]
    unless out
      out = firpm.to_a
      @@firpm_cache[firpm.options] = out
      f.truncate 0
      YAML::dump @@firpm_cache, f
    end
  end
  out
end

.hamming_window(array, w = nil) ⇒ Object 



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# File 'lib/radio/utils/window.rb', line 31

def hamming_window array, w = nil
  hamming_window! array.dup
end

.hamming_window!(array, width = nil) ⇒ Object 



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# File 'lib/radio/utils/window.rb', line 20

def hamming_window! array, width = nil
  n = -1
  width ||= array.size
  w = width - 1
  array.collect! do |v|
    n += 1
    0.54 - 0.46 * Math.cos((PI2 * n) / w)
  end
end

.kaiser_estimate(options) ⇒ Object 



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# File 'lib/radio/utils/misc.rb', line 23

def kaiser_estimate options
  ripple = options[:passband].to_f * options[:stopband]
  numer = -20.0 * Math.log10(ripple) - 13
  denum = 14.6 * options[:transition]
  taps = (numer/denum).round
  type = options[:type] || :odd
  if type == :even
    taps +=1 if taps.odd?
  else
    taps +=1 if taps.even?
  end
  taps
end