Which pulse modulation scheme is used as an intermediate step in the creation of PCM?

The pulse amplitude modulation (PAM) scheme is used as an intermediate step in the creation of pulse code modulation (PCM). In PAM, the amplitude of discrete pulses represents the sampled values of the analog signal. These amplitude levels are then quantized and encoded into a binary format to produce the final PCM signal. This process enables the efficient digital representation of analog information for transmission and storage.