A-CELP is an Algebraic code-excited linear prediction which is a speech coding algorithm. In this, a limited set of pulses is distributed as excitation to a linear prediction filter. This method is commonly used in speech coding techniques like AMR (Adaptive Multi-Rate), AMR-WB, etc. To model noise, CELP codecs usually use a vector codebook. CELP codecs using algebraic coding are known as Algebraic CELP or ACELP.