======================CREST_FACTOR======================================== Crest_factor peak(abs(waveform))/rms(waveform) ---------------------------------------------------------------------------- Wave type Mean mag rect Waveform factor RMS Crest factor Crest factor (dB) DC 1 1 1 0.0 dB Sine wave 2/Pi Pi/2^1.5 1/2^0.5 2^0.5 3.01 dB Full-wave rect sine 2/Pi Pi/2^1.5 1/2^1/2 2^0.5 3.01 dB Half-wave rect sine 1/Pi Pi/2 1/2 2 6.02 dB Triangle wave 1/2 2/3^0.5 1/3^0.5 3^0.5 4.77 dB Square wave 1 1 1 1 0 dB PWM-Signal t1/T (T/t1)^0.5 (t1/T)^0.5 (T/t1)^0.5 QPSK 3.5 - 4 dB 8VSB 6.5-8.1 dB [1] 64QAM 7.7 dB 128QAM 8.2 dB ---------------------------------------------------------------------------- rm = 1.0 peak = 1.0 ave = 1.0 crest factor = 1.0/1.0 = 1 ____ | | ____| |___ CONTINUOUS DIRECT CURRENT ---------------------------------------------------------------------------- _--_ / \ ____| |____ peak 1.0 crest factor = 1.0/0.707= 1.414 rms = 0.707 average = 0638 SINEWAVE FULL HALF-CYCLES ---------------------------------------------------------------------------- |\ ____| |____ peak 1.28 crest factor = 1.28/0.32 4.O0 rms = 0.32 average 0.11 LATE PHASE ANGLE LAMP DIMMER ---------------------------------------------------------------------------- ^ / \ | | ____/ \__ peak=1.414 crest factor = 1.414/0.22 = 6.42 rms = 0.22 average = 0.04 TYPICAL AC LINE POWER SUPPLY