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• CCITT Rec. O.41 (11/1988) – PSOPHOMETER FOR USE ON TELEPHONE-TYPE CIRCUITS
• 1 Introduction
• 2 General
• 3 Specific requirements
  • 3.1 Input impedance
  • 3.2 Longitudinal losses
  • 3.3 Measuring range
  • 3.4 Calibration accuracy at 800 Hz
  • 3.5 Relative gain versus frequency (frequency weighting)
  • 3.6 Detector circuit characteristics
  • 3.7 Detector and display dynamics (measurement averaging time)
  • 3.8 Linearity
  • 3.9 Output indicator
  • 3.10 Operating environment
• ANNEX A (to Recommendation O.41) Comparison of CCITT and North American weightings