704 Leading Edge Discriminator



Utilizing the most advanced technology, the Model 704 Quad Discriminator boasts a 300 MHz continuous repetition rate capability. The updating feature ensures deadtimeless operation for coincidence applications, while the double-pulse resolution is a remarkable 3.3nSec for counting applications. A fifteen-turn potentiometer provides continuous output width adjustment from 2nSec to over 50nSec for each channel.

The threshold is variable from -10mV to -1volt with a fifteen-turn potentiometer on each channel. The threshold setting is easily determined from a front panel test point that provides a DC voltage equal to ten times the actual threshold.

Inhibiting of the discriminator can be accomplished in two ways. A front panel LEMO input accepts a NIM level pulse for fast vetoing of all channels. The fast veto is capable of inhibiting a single pulse from a 300 MHz input pulse train. Secondly, a slow bin gate via the rear panel connector inhibits all four channels and is enabled or disabled from a rear panel slide switch.

The outputs are the current source type with two pairs of negative bridged outputs and two complements for each channel. When only one output of a bridged pair is used, a double-amplitude NIM pulse (-32mA) is generated, useful for driving long cables with narrow pulse widths. The outputs have transition times of 1nSec, and their shapes are virtually unaffected by loading the outputs in any combination.