The LRS Model 465 contains three independent high-speed general-purpose coincidence units in a single-width NIM module. Each channel has four coincidence inputs and a separate veto input which accept standard negative NIM logic levels. The logic inputs may be individually enabled or disabled without altering input cabling or termination by means of front-panel pushbutton switches. With all inputs enabled, four inputs are required. Disabling the logic inputs is equivalent to reducing the number of simultaneous negative inputs required for an output. Thus, each channel may be programmed for 4-fold, 3-fold, or 2-fold logic decisions. With only one input enabled, each channel of the 465 operates as a logic fan-out.
Once triggered by signals satisfying the input coincidence requirements, the 465 generates five NIM fast logic outputs: one pair of -32 mA negative preset outputs, one - 1 6 mA preset complementary output, and one pair of -32 mA overlap outputs. The preset outputs are continuously adjustable from less than 5 ns to greater than 500 ns by means of a front-panel multiturn potentiometer and are independent of input overlap time, amplitude, and rate. Because it is updating, it may be retriggered even before the end of an output pulse that is already present. The overlap outputs are equal in duration to the coincidence overlap and produce outputs up to the maximum input rate capability.
The front-panel fast veto input accepts standard negative NIM-level pulses. To veto the linear outputs, the veto signal must completely overlap any input coincidence; to veto the preset outputs, a prompt overlap of the leading edge of the input signal that would otherwise create the coincidence condition is required. A rear-panel bin-gate switch permits a slower (50 ns response time) inhibiting of the 465 by a clamp to ground from +4 volts through the bin gate pin of the rear power connector.
The Model 465 is packaged in a standard AEC/NIM #1 module (AEC Report TID-20893) and uses exclusively Lemo-type front panel connectors.
NIM Model 465 TRIPLE 4-FOLD LOGIC UNIT
SPECIFICATIONS
|
INPUT CHARACTERISTICS |
|
|
Logic Inputs: |
4; Lemo-type connectors; 50Ohm impedance; negative NIM-level input require- ments; each input can be separately enabled or disabled by front-panel push- buttons. |
|
Veto Input: |
Standard negative NIM-level signal, 3.5 ns minimum width. Requires complete overlap of input coincidence for linear outputs and prompt overlap of the leading edge of the input signal that would otherwise create the coincidence condition for the preset outputs. (Veto should precede this leading edge by approximately 5 ns in this case.) |
|
Bin Gate: |
Via rear connector; clamp to ground from +4 volts inhibits; risetimes and fall- times < 50 ns. |
|
OUTPUT CHARACTERISTICS |
|
|
Preset Outputs: |
3; one dual negative (quiescently 0 mA, -32 mA during output), one positive (quiescently -16 mA, 0 mA during output). Updating. |
|
Overlap Outputs: |
One dual negative; quiescently 0 volts, -32 mA during output; duration equal to coincidence overlap. Non-updating. |
|
Fan-Out: |
5-fold, if each output drives a 50OHm load. |
|
Duration: |
Continuously adjustable from less than 5 ns to greater than 500 ns by means of front-panel, screwdriver-adjustable potentiometer. Width stability: better than +/- 0.2%/'C maximum. |
|
Output Risetimes:* |
OUT: <=2.0 ns typical (max. 2.2 ns). |
|
Output Falltimes:* |
OUT: <=2.0 ns typical (max. 2.5 ns). Slightly longer
on wide output durations. |
|
GENERAL |
|
|
Logic: |
2-fold, 3-fold, or 4-fold coincidences plus fan-out determined by selectively dis- abling logic input. |
|
Coincidence Width: |
1 ns up, determined by input pulse durations. |
|
Rate: |
120 MHz minimum. |
|
Input-Output Delay: |
13 ns preset; 8.5 ns linear. |
|
Multiple-Pulsing: |
None; one and only one output pulse of preset duration is produced each time the input conditions are satisfied regardless of the duration of the input pulses or their overlap. |
|
Double-Pulse Resolution: |
8 ns. |
|
Packaging: |
Single-width AEC/NIM module; in conformance with AEC standard; Lemo-type connectors used for all inputs and outputs. |
|
Current Requirements: |
+12 V at 65 mA |
|
|
|