CO4020 Quad 4-Input Logic Unit

• General-purpose logic module for AND, OR, Veto, Fan-Out, and Gating functions
• Four independent channels
• Overlap outputs and adjustable-width outputs
• 3-ns overlap resolution
• TTL and fast negative NIM outputs

The ORTEC Model CO4020 Quad 4-Input Logic Unit has the flexibility to satisfy the logic requirements of most coincidence experiments without additional logic modules. The logic functions it can perform are: coincidence (AND), anticoincidence (veto), fan-in (OR), fan-out, fast negative NIM-to-TTL conversion, and pulse lengthening. The Model CO4020 contains four identical, independent channels of 4-input logic in a single-width NIM module.

Each of the four inputs (A, B, C, and D) accepts NIM fast negative logic pulses. Front-panel, three-position slide switches select the logic requirements separately for each input. The various combinations of logic functions that can be implemented are illustrated in Fig. 1 and in the specifications for the control switches.

The X output is a NIM fast negative logic pulse whose width is determined by the width and overlap of the active input pulses. The complement of the X output is available at the output. The updating Y outputs can be set to trigger on either the leading edge or the trailing edge of the X output pulse. The width of the Y outputs can be adjusted from 40 ns to 4 0 µs in two selectable ranges. Two of the Y outputs provide NIM fast negative logic pulses. The third Y output delivers a positive TTL logic pulse that is suitable for gating ADCs and multichannel analyzers. Front-panel LEDs indicate which channel is generating an output.

Fig. 1. Block Diagram of the Model CO4020 Logic Unit.

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