The Quadra is a quad function / envelope generator module by Intellijel with a 4 x function generators and 3 modes:
1 ad (attack - decay)
2 ahr (attack - hold - release)
3 cycle (ad envelope loops)
Each function can have a linear or exponential curve.
The wide time range for attack/decay controls is: <0.5ms to well over 30s.
All analog and discrete logic for function generation (smooth and continous waveforms).