Demodulation references are short messages exhibiting modulation levels of a modulation scheme, to assist the receiver in demodulating a message. Disclosed are short-form demodulation references suitable for pulse-amplitude modulation (PAM) messages in 5G and 6G. Each resource element of the short-form PAM demodulation reference provides two amplitude calibrations, one for each I or Q branch, from which the remaining amplitude levels of the modulation scheme can be readily calculated in real-time. The receiver can then demodulate a message by matching the branch amplitude values of each message element to the calibrated amplitude levels as determined from the demodulation reference. To indicate the start and end of the message, different configurations can be placed before and after the message. To mitigate high levels of background, a short single-symbol demodulation reference can be embedded in the message at multiple positions. Configurations are suitable for adoption as a demodulation standard.