ATOM's Tremolo is an FX unit that uses an automated LFO to automatically reduce the volume of your signal at specified depth and speed, which gives the audio a cool pulsing sound.

The Tremolo FX unit can be found in the FX section of ATOM:

The unit begins as the sixth FX unit from the top, and can be turned on by clicking the top right power icon or the left-side light in the FX module of the fx rack section:

When the Tremolo section's power icon is lit blue it means the plugin is on.

"Sync," syncs the Tremolo effect to the BPM of your DAW.

"Rate," Determines how quickly the Tremolo effect is applied. If the "Sync," button is activated these parameters will be based on your DAW, if not they will be numbered as Hz.

"Depth," refers to how intensely the Tremolo effect is applied. Higher depth values will make the pulsing sound more audible.

"Shape," alternates the type of pumping effect you hear by changing the LFO waveform used to make the effect. Sin sounds more subtle, while Triangle sounds more noticeable.

"Width," determines how wide in the stereo field the Tremolo signal is. Lower values make the signal more centered, while higher values make the signal sound wider.

"Mix," is essentially a dry/wet knob for the Tremolo. A Mix of 0 means no Tremolo effect is applied, while a Mix of 100 means the entire signal is run through the Tremolo modulation.