Two words people use interchangeably
In casual lab talk, "pulse generator" and "delay generator" get swapped freely. The hardware tells a sharper story. A delay generator answers the question when. It takes a reference event, called T0, and produces a clean edge a precise interval later. A pulse generator answers what. It produces an output with a defined amplitude, width, polarity, and edge speed, the signal that actually drives a load.
Most Berkeley Nucleonics instruments do both. A single channel on a Model 577 sets a delay from trigger, then emits a pulse of programmed width. The distinction still matters, because it tells you which specifications to weigh first. If you are timing a flashlamp before a Q-switch, resolution and channel-to-channel skew dominate. If you are driving a Pockels cell or a 50 ohm detector, amplitude and rise time take over.
When you need delay output
Reach for delay-first behavior when many things must happen in a fixed sequence relative to one start. Laser triggering is the classic case: flashlamps fire, the pump settles, then the Q-switch opens, then a camera gates. Each step is a channel referenced to T0 with its own delay. Particle Image Velocimetry and LIBS work the same way, with two laser pulses and a camera straddling them by microseconds or less.
Here the output is usually a logic-level edge. TTL or CMOS into high impedance is enough to trigger the next box. What you care about is that the edge lands where you asked, shot after shot, with low jitter and minimal drift between channels. The 575, 577, 588, and 588B are built around this model, with 250 ps resolution and independent delay and width per channel.
When you need pulse output
Reach for pulse-first behavior when the output drives something directly. A laser diode, an electro-optic modulator, a sample under test, a 50 ohm transmission line. Now the edge speed and amplitude are the product, not an afterthought. A logic pulse that is electrically correct in timing can still be useless if its rise time is too slow or its level too low for the load.
This is where the 765 family lives. The Model 765 delivers sub-70 ps rise and fall times with adjustable amplitude from 10 mVpp to 5 Vpp into 50 ohms, plus baseline offset. The Model 765-HV pushes amplitude to plus or minus 50 Vpp while holding rise time under 400 ps. The current pulsers, Model 507 and Model 508, are pulse generators in a different domain entirely: they source current, not voltage, into low-impedance initiators.
Output types you will meet
The output connector hides most of the engineering. A few categories recur across the line.
TTL / CMOS logic. A roughly 4 V edge into high impedance, the default trigger language between instruments. Standard on the 525, 575, 577, 588, and 588B.
Adjustable amplitude. A programmable level, commonly 2 to 20 V, for loads that need more than logic swing. Available as output-module options across the 500-series.
50 ohm matched. Required for fast edges and long cables without reflections. The 765 is natively 50 ohm; the 500-series offers it through TZ-class modules.
High voltage. Tens of volts of swing for Pockels cells, gating, and beam control. The 765-HV reaches plus or minus 50 Vpp; the 745T offers a 32 V module (GFT632, with a 70 V option, verify).
Current. Amperes into a fixed low resistance, for firesets and initiators. The 507 sources up to 25 A; the 508 up to 6 A with measurement and safety interlocks.
Channel counts and where they cluster
Channel count usually follows the application, not the price. Multi-step laser and imaging sequences want 4 to 8 channels. Dense synchronization across a large experiment wants more. The 588B carries 12 or 24 independent channels, up to 36 outputs in advanced configurations, in a 2U chassis. At the other end, the 765-HV may ship as a single channel because each channel is an expensive high-voltage front end.
Model map at a glance
| Model | Primary role | Channels | Output type | Headline spec |
|---|---|---|---|---|
| 525 | Delay + pulse, portable | 6 | TTL | 4 ns resolution, USB-powered |
| 575 | Delay + pulse, flexible I/O | 2 / 4 / 8 | TTL, adjustable, optical, HV options | 250 ps resolution, up to 10 MHz |
| 577 | Delay + pulse, benchtop | 4 / 8 | TTL, adjustable, optical, HV options | 250 ps resolution, up to 20 MHz |
| 588 | Delay + pulse, 1U rackmount | 4 / 8 | TTL / 20 V adjustable | 250 ps resolution, <50 ps jitter |
| 588B | Delay + pulse, high density | 12 / 24 | TTL / 20 V adjustable | 250 ps resolution, <5 ps jitter |
| 725 | Multi-trigger logic | 8 in / 8 out | TTL-compatible | 10 ns resolution, programmable logic |
| 745T | Femtosecond delay | 4 / 8 | 5 V into 50 Ω, HV module option | 1 ps resolution, ~5 ps jitter |
| 765 | Fast pulse | 2 / 4 | 50 Ω, 10 mVpp–5 Vpp | <70 ps rise time, 800 MHz |
| 765-HV | Fast high-voltage pulse | 1 / 2 | 50 Ω, up to ±50 Vpp | <400 ps rise time, 400 MHz |
| 507 | High-current pulse | 2 / 4 | Current, up to 25 A | 200 ns resolution, fireset |
| 508 | Precision current pulse | 2 / 4 | Current, up to 6 A | 10 ns jitter, measurement + safety |
Values are drawn from current Berkeley Nucleonics dossiers and are subject to verification against the latest released datasheet. Confirm any critical number before designing it into a system.
How to choose in one pass
Start with the load. If something downstream needs a specific voltage, current, or edge speed, you are choosing a pulse generator and the output stage decides the model. If the downstream boxes only need a clean trigger, you are choosing a delay generator and resolution, channel count, and jitter decide it. Then check the count of distinct timed events. That sets how many channels you need, and often which chassis.
Talk to an application engineer
Send us the loads, the sequence, and the timing budget. We will map it to the right channel count and output type and flag anything that needs verification against the released datasheet. Reach Berkeley Nucleonics at info@berkeleynucleonics.com or 800-234-7858, or browse the full Pulse & Delay Generators documentation.