Pulse-amplitude modulation

[3] GDDR6X, developed by Micron[4] and Nvidia and first used in the Nvidia RTX 3080 and 3090 graphics cards, uses PAM-4 signaling to transmit 2 bits per clock cycle without having to resort to higher frequencies or two channels or lanes with associated transmitters and receivers, which may increase power or space consumption and cost.

PAM-4 costs more to implement than earlier NRZ (non return to zero, PAM-2) coding partly because it requires more space in integrated circuits, and is more susceptible to SNR (signal to noise ratio) problems.

The higher data transmission rate per cycle compared to NRZ/PAM-2-signaling used by GDDR6 and prior generations improves power efficiency and signal integrity.

[8] The concept is also used for the study of photosynthesis using a specialized instrument that involves a spectrofluorometric measurement of the kinetics of fluorescence rise and decay in the light-harvesting antenna of thylakoid membranes, thus querying various aspects of the state of the photosystems under different environmental conditions.

[10] Pulse-amplitude modulation has also been developed for the control of light-emitting diodes (LEDs), especially for lighting applications.

[11] LED drivers based on the PAM technique offer improved energy efficiency over systems based upon other common driver modulation techniques such as pulse-width modulation (PWM) as the forward current passing through an LED is relative to the intensity of the light output and the LED efficiency increases as the forward current is reduced.

[12] It uses additional processing to suppress one sideband and thus make more efficient use of limited bandwidth.

Using a single 6 MHz channel allocation, as defined in the previous NTSC analog standard, 8VSB is capable of transmitting 32 Mbit/s.