:::..BNC | Products | Model PB-4 Precision Pulse Generator

Repetition Rate
2.5 Hz to 250 kHz, continuously variable.

External Trigger
0 to 250 kHz. Requires 1 V, positive pulse, with a rise time of less than1 ms.

Single Cycle
Front panel push-button provides one output pulse each time the button ispressed.

Delay
0.25 us to 10 ms. continuously variable. (Delay is time between triggerout and pulse out.)

Pulse Shape
Tail or flat top pulse (by front panel toggle).

Tail Pulse
Rise Time (10%-90%): 0.05 us to 10 us, in 8 steps.
Decay Time Constant (100%-37%): 0.5 us to 1 ms, in 9 steps.
Rise and Decay Time Independently Adjustable for Decay Time/Rise Time >10.

Flat Top Pulse
Width: 0.5 us to 25 us, continuously adjustable.
Pulse Top Droop: less than 0.02% with 10 us pulse width.
Rise and Decay Time: Same as tail pulse.

Pulse Top
Stability: +/-5 ppm/°C of full scale or 20 uV/°C, whichever is greater.This specification holds for unattenuated output. When attenuation is switchedin, the +/-5 ppm/°C is constant, while 20 uV/°C is reduced by theattenuation factor.
Integral Non-Linearity: +/-0.005% (50 ppm).
Differential Non-Linearity: +/-0.03%.
Amplitude Jitter (Resolution): 0.001% rms (10 ppm).
Setability of Pulse Amplitude: 5 ppm.
Line Voltage Coefficient: Lessthan 0.5 ppm/V when used with a NIM power supply or Berkeley NucleonicsPortanim Models AP-1 and AP-2H

Amplitude
0 to 10 Volts.

Normalize
Fine and coarse front panel trimmers vary output amplitude by 20%.

Polarity
Positive or negative.

Attenuators
Four toggles with X2, X5, X10, X10 attenuation,50 ohms impedance.

Output Impedance
50 ohms +/-2%.

Amplitude Shift with Duty Factor
Less than 0.03% change up to 50% duty factor.

Repetition Rate and Delay Jitter
Less than 0.05%.

Trigger Output
2 V positive pulse, 30 ns rise time, 0.1 us width, 50 ohms output impedance.

External Reference Input
+/-11 V maximum. Input impedance 1 k. Primary function is to connect with anexternal ramp generator to provide a sliding pulse train.

Power Required
+/- 24 V at 240 mA.

Mechanical Dimensions
Triple-width AEC module 4.05" wide x 8.70" high in accordancewith TID-20893 (Rev. 3).

Weight
6 l/2 lbs. net, 9 lbs. shipping.

Companion Instruments

Model AP-1 Portanim, portable carrying case and power supply.

Model LG-1 Ramp Generator.

Accessories

Connecting cable between LG-1 and PB-4, 7" length, BNC to BNCconnectors.
BNC Part No. 6014.

Berkeley Nucleonics is now able to offer unprecedented specifications andversatility in a precision pulse generator. The Model PB-4 provides eithera tail or flat top pulse with an integral linearity of +/-50 ppm and an amplitudetemperature coefficient of +/-5 ppm/°C. The Model PB-4 is designed totest stability, linearity, and resolution of nuclear instruments employedin high resolution spectroscopy. It also offers the high count rates thatare so important in many of these tests.

Features

• Flat Top or Tail Pulse

• Rep Rate 250 kHz .

• Rise and Fall Times Independently Adjustable

• Output Impedance 50 ohms

• Temperature Coefficient+/-5 ppm/°C

• Integral Linearity +/-50 ppm

• Amplitude shift less than 0.03% at 50% duty factor

Applications

• Use as a reference peak for spectrum stabilization

• Testing count rate effects up to 250 kHz

• Measuring differential and integral linearity of pulse height analyzers

• Measuring noise from preamplifiers and amplifiers

The Model PB-4 employs a solid state chopper (no mercury relays) which sampleseither an internal DC reference voltage or an externally supplied referencesource. The output of the chopper is connected to a high gain, fast slewrate operational amplifier to provide the possibility of driving heavy loads.The internal DC reference source, the chopper and the operational amplifierare all enclosed in a proportional control oven whose internal temperaturechanges only 0.01°C for a 1°C change in ambient.

A sliding pulse generator provides a pulse train of linearly increasing(or decreasing) pulses to test the differential linearity of multi-channelpulse height analyzers. To obtain a sliding pulse train from the Model PB-4it is necessary to connect a Berkeley Nucleonics Model LG-1 Ramp Generatorto its External Reference input. See diagram below. The solid-state chopperin the Model PB-4 samples the ramp at periodic intervals. The output ofthe Model PB-4 is then connected to the pulse height analyzer. If the analog-digitalconverter is linear and the magnetic core storage is functioning correctly,an equal number of counts will be stored in each channel and the displaywill be a horizontal straight line as at A. However, if the analyzer isnon-linear the display may curve up as at B. If the magnetic core storageis defective there may be a notch in the display as at C. The differentiallinearity of the sliding pulse train is better than +0.1%. The above approachis the fastest, most accurate way of testing a pulse height analyzer.

Now, Berkeley Nucleonics offers the Model PB-5. This upgrade to the Model PB-4 includes a built in ramp and full programmability. This allows faster test protocols to be performed and gives the end user a repeatable approach to linearity measurements and verification. See the Model PB-5 for more here.

Berkeley Nucleonics Corporation

2955 Kerner Blvd., San Rafael CA 94901 U.S.A

Phone: 800.234.7858 Fax: 415.453.9956

E-mail: info@berkeleynucleonics.com