Ortec T140/N Quad Zero-X Discriminator

1.1 GENERAL

The T140/N QUAD ZERO-CROSSING DISCRIMINATOR Module (Fig. 1) is designed for low cost per channel in applications where many discriminators are required. Each T140/N Module contains four independent discriminators.

The unit may be operated in the zero-crossing mode, to provide excellent timing at high repetition rates with relative independence from input signal amplitude variations and noise. The T140/N combines both amplitude discrimination, for noise independence, with zero-crossing discrimination to minimize dispersion due to amplitude and risetime variations of photomultiplier signals.

The T140/N may also be operated as a conventional leading-edge integral discriminator for positive signals. Gating in either mode is provided via the system gating line, to allow many T140/N modules to be simultaneously inhibited or enabled.

1.2 SPECIFICATIONS

INPUT

Protected limiting input for photomultiplier signals. 50 ohm input impedance, with less than 10% reflections from -10 V, 1 nSec risetime signals. Maximum non-destructive input limits: +/-5 V dc; +/-10 V, 100 nSec pulses of duty-factor less than 10%; +/-100 V fast transients. Overload recovery typically 2 nSec from -5 V input.

THRESHOLD

Typically -200 mV (-250 mV maximum) in zero-crossing mode; typically +250 mV in leading-edge mode.

OUTPUT

"Dual" NIM-standard fast logic signal * output, for fanout factor of two. T₀₁ and T₁₀ less than 2 nSec. Width adjustable by recessed front-panel multiturn control from less than 5 nSec to greater than 10 nSec.

DELAY

Typ. 8 nSec, from input zero-crossing to half-amplitude output.

MAXIMUM RATE

Typ. +/-150 pSec from threshold crossing detector maintains timing to typ. 250 MHz.

SLEWING

Typ. +/-150 nSec from threshold to 10X threshold in zero-crossing mode; typ. less than 1 nSec from threshold to 10X threshold in leading-edge mode.

GATING

Switch-selected NIM-standard slow logic signal gating via system gating line at power connector. -2 V to +1.5 V or low impedance to ground inhibits unit; +3 V to +12 V or high impedance to ground enables unit. Gate input impedance greater than 2.5 K.   Gate response time less than 50 nSec for +5 V gating signal.

Temp. Range

-15'C to +60'C

Power Req.

+24 V, 210 mA.
+12 V, 220 mA.
- 12 V, 190 mA.
- 24 V, 195 mA

Panel Color

Black

*    ZERO = 0 +/- 50 mV
        ONE   800 +/- 100 mV
        T₀₁ denotes -100 mV to -600 mV transition
        T₁₀ denotes -600 mV to -100 mV transition.

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INPUT	Protected limiting input for photomultiplier signals. 50 ohm input impedance, with less than 10% reflections from -10 V, 1 nSec risetime signals. Maximum non-destructive input limits: +/-5 V dc; +/-10 V, 100 nSec pulses of duty-factor less than 10%; +/-100 V fast transients. Overload recovery typically 2 nSec from -5 V input.
THRESHOLD	Typically -200 mV (-250 mV maximum) in zero-crossing mode; typically +250 mV in leading-edge mode.
OUTPUT	"Dual" NIM-standard fast logic signal * output, for fanout factor of two. T₀₁ and T₁₀ less than 2 nSec. Width adjustable by recessed front-panel multiturn control from less than 5 nSec to greater than 10 nSec.
DELAY	Typ. 8 nSec, from input zero-crossing to half-amplitude output.
MAXIMUM RATE	Typ. +/-150 pSec from threshold crossing detector maintains timing to typ. 250 MHz.
SLEWING	Typ. +/-150 nSec from threshold to 10X threshold in zero-crossing mode; typ. less than 1 nSec from threshold to 10X threshold in leading-edge mode.
GATING	Switch-selected NIM-standard slow logic signal gating via system gating line at power connector. -2 V to +1.5 V or low impedance to ground inhibits unit; +3 V to +12 V or high impedance to ground enables unit. Gate input impedance greater than 2.5 K. Gate response time less than 50 nSec for +5 V gating signal.
Temp. Range	-15'C to +60'C
Power Req.	+24 V, 210 mA. +12 V, 220 mA. - 12 V, 190 mA. - 24 V, 195 mA
Panel Color	Black