Spurious / Unwanted Radiation

  • Even a “linear” amplifier has some residual non-linearity leading to harmonic generation
  • Over-driving an amplifier makes it non-linear
  • Unwanted mixer and intermodualtion products
  • Self oscillation where an amplifier oscillates near the working frequency
  • Spurious (parasitic) oscillations where internal feedback causes an amplifier to oscillate at a frequency not necessarily related to the working frequency
  • Spurious signals from frequency synthesisers
  • Excessive audio bandwidth and over modulation or over deviation