The Model 365 and 365N are dual 4-fold logic units which offer the functions of fan-in, coincidence, loading edge inhibit, majority logic, and pulse standardization. Each of two identical channels accepts standard NIM logic signals at each of the four logic inputs and one veto input. All inputs are terminated in 50 Ohm. Lemo-type connectors are used with the single-width Model 365; BNC type connectors are used with the double-width Model 365N.
A front-panel selector allows programming the number of simultaneous negative inputs required for an output. With its majority logic capability, the unit may be used to perform voter coincidence such as 1 of 1, 2, 3, 4 (logic fan-in), 2 of 3, 4, or 3 of 4 as well as the standard coincidences of 2 of 2, 3 of 3, 4 of 4. Any of the inputs serves as an inhibit input when driven with a complementary logic signal . A separate veto input is provided for inhibiting the output regardless of the state of other inputs. This veto signal need only overlop the leading edge of the coincidence in order to inhibit the output.
Both channels of the 365 may be gated off by means of the NIM bin gate. The bin gate enters the module via the rear multipin power connector and a rear-panel On-Off switch. Quiescently at + 5 volts, the bin gate must be clamped to ground to inhibit the logic unit. The bin gate is direct-coupled, and has rise and fall times of approximately 50 ns.
A front-panel selector is provided for programming the participating inputs. Inserting the programming pins in any of the designated Off positions disables that input and eliminates the necessity of removing input cables. A separate storage location is provided for holding the programming is not in use.
Once the input coincidence conditions have been satisfied, the Model 365, 365N generates three double-amplitude NIM fast logic outputs. Each output is provided with two paralleled connectors to enable the signal to be clipped, back-terminated, or fanned-out to two 50 Ohm loads. The positive output, or complement UT , is quiescently at a logical one state (-32 mA) and switches to 0 mA (or 0 volts) for the duration of the output. The two negative outputs (OUT) are quiescently at zero and switch to - 32 mA (-800 mV if both connectors drive 50 Ohm loads) during an output.
The output duration of each channel is adjustable by means of a front-panel potentiometer from 3.5 ns to 50 ns.
The Model 365, 365N is a deadtimeless circuit and will respond to input signals even when an output is already present. The minimum pulse pair separation is under 6 ns for an equivalent CW rate of greater than 150 MHz. If a second coincidence is detected during the time the output from a first coincidence is being produced, the unit will extend the output duration to reflect the occurrence of the second signal . The net output pulse, being the logical sum of two standard output pulses, is of standard amplitude and retains the time information contained in the input signals.
The Model 365 offers non-multiple-pulsing operation to assure unambiguous response to input pulses regardless of their amplitude or duration. The 365 will not produce multiple pulses even with input pulses that substantially exceed the output pulse in duration.
SPECIFICATIONS
Number of Channels: Two, all identical.
Input Levels: NIM logic levels: logical 0, 0 mA +/- 2 mA; logical 1,
16 mA +/- 2 mA.
Input Impedance: 50 Ohm +/-5%; value of impedance is constant up to the
limit of input protection for negative inputs.
Input Protection: +/- 5 volt protection for pulses. DC overload character-
istics are determined by the 250 mW dissipation limit of the 50 Ohm input
terminating resistor.
Input Coupling: Direct; coupling is independent of input risetime,
duration, and rate.
Input Reflections: Dependent upon input risetime; less than 10% for in-
put signal of 2 ns risetime or greater.
Gate: Logic unit may be inhibited by application of NIM Bin Gate.
Bin Gate enters module via pin of rear multipin connector. Switch
located on back panel disconnects 365 from Bin Gate line. Clamping
Bin Gate to ground from + 5 volts inhibits. Clamping circuit must
sink 3 mA per module. Bin Gate circuit is direct-coupled . Rise
and fall times are 20 ns.
Negative Outputs: Two, both with paralleled connectors driven by
common high impedance current source. Quiescently, 0 mA,
current source switches to - 32 mA during output.
Positive Output: One, complementary, paralleled connectors, quiescently
- 32 mA - .6 mV into 50 OHm load), switching to zero volts during
an output.
Output Duration: 4ns FWHM to 50 ns, continuously adjustable by means
of front-panel width control .
Output Rise and Fall Times: 1.2 ns typical, 10% to 90%; fall time slightly
longer on wider widths.
Output Duration Stability: Less than 0. 1%/'C from 20'C from 60'C.
Coincidence Width: 1 ns up, determined by input pulse duration.
Double Pulse Resolution: Minimum separation to resolve two pulses is
typically under 6 ns.
Maximum Rate: 160 MHz typical, input and output; defined for input
signals of - 600 mV, 3.5 ns FWHM.
Functions: ANDing, ORing, Majority, Inhibit and Complementary logic.
Input-Output Delay: 8. 0 ns +/- 5% channel -to-channel variation; jitter
< 20 ps rms.
Counting Efficiency: Deadtimeless operation; recovery time is less than
output pulse duration; there is no deadtime following output pulse at
output durations greater than 8 ns; output duration will update to
reflect new input if retriggered while output pulse is present.
Multiple Pulsing: None; one and only one output pulse is produced for
each input pulse regardless of input pulse amplitude or duration.
Power Requirements: 8.8 watts total; + 12 volts at < 120 mA, - 12 volts
at 60 mA, 120 VAC at 33 mA; voltages must be regulated to +/- . 1%.
Packaging: The Model 365, 365N are packaged in conformance with AEC
standard for nuclear modules (AEC Report TID 20893 Rev.) Completely
compatible physically and electrically with LRS Power Chassis Model
108P, and with any other AEC standard power bin of any manufacturer.
Model 365 is single-width module using Lemo-type connectors and
Model 365N is double-width module using BNC-type connectors.