PCM c o d a have stringent gain and dgnd-to-total distortion t a t requiremento. Tat tort L rubetantial due to long ( . ! 10 I) real-time stimulation period and high cost oftest equipment. A new tat method L d o scribed which allom full gain and SNR curvea to be measured ~t h m u m r e m n t period of under 2 6 with better than 0.1 dB signal level qncing. A trampored t a t coniiguration ir wed which avoids the need for dowed tone ir the tert a i g d . The entire gain and SNR ventu signal level curvcs are derived from one stimult~tion. Reference curve6 for the new tart signal for A-Law c o d a reaemble smoothed v a r i o~ of thone for CCITT Method 2.analog t a t signal &ulaation. An exponentidly will-