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Product Data Sheet

Model 745T 4/8 Channel Pulse & Delay Generator

A high-resolution pulse and delay generator powered by Greenfield Technology, with four independent delay channels at 1 ps resolution, 5 V into 50 ohm outputs, and an optional four auxiliary channels for laser timing, ATE, and precision instrument triggering.

Model 745T · Product Data Sheet · V11/20
Berkeley Nucleonics Model 745T 4/8 channel pulse and delay generator, front panel showing the touchscreen and channel A to H BNC outputs

1Overview

The Model 745T generator, powered by Greenfield Technology, provides four independent delay channels (A to D) on the front panel. The delay resolution is 1 ps, and the external trigger-to-channel jitter is less than 25 ps. BNC output connectors deliver 5 V, 1 ns rise-time into 50 Ω. Amplitude and width are adjustable for each output pulse.

A T0 output pulse, marking the zero delay reference, is generated at each selected trigger. Trigger sources include a RUN/STOP button, one input trigger (TRIG IN), two internal Timers, or software commands, and may be used to trigger individual output channels or all output channels.

The Model 745T also provides, as an option, four auxiliary delay channels E to H on the front panel. The delay resolution is 1.25 ns and the trigger-to-channel jitter is less than 50 ps.

All parameters (delay, pulse amplitude, width, and trigger source) may be locally controlled over the touch panel or remotely controlled over the Ethernet and Internet interface through the internal webserver.

2Features & Applications

Features

  • Four high-resolution delay channels. 1 ps resolution, <5 ps RMS jitter (at short delay), 20-second delay range.
  • Output pulse 5 V, 1 ns rise-time into 50 Ω, adjustable in amplitude and width.
  • Trigger rates. Burst, Gate, External trigger prescaler, Internal frequency generators.
  • External clock. 10 MHz or 100 MHz.
  • Compact packaging.
  • Full control. All parameters may be controlled via the front panel, Ethernet or Internet, or USB.
  • Option. Four auxiliary delay channels.

Applications

  • Component Testing
  • ATE Applications
  • Laser Timing Control
  • Laser Pulse Picking
  • Precision Pulse
  • Instrument Triggering
  • Embedded OEM application (in option)

3Specifications

Delay channels A to D

ParameterSpecification
Number4 independents (or 8 in option)
Range0 to > 20 seconds
Resolution1 ps
RMS jitter25 ps + delay x 10⁻⁸ (external trigger to any output)
5 ps + delay x 10⁻⁸ (internal trigger to any output)
Accuracy< 250 ps + delay x 10⁻⁸
Timebase0.05 ppm stability

External Trigger Mode

ParameterSpecification
Input “TRIG”Threshold = 0.1 to 5 V into 50 Ω, Slope = positive or negative
Repetition rateSingle, Repetitive < 1 MHz, or Burst mode
Trigger prescaler1 to 2¹⁶-1
Trigger delay< 65 ns (insertion delay)

Internal Trigger Mode

ParameterSpecification
Rate repetitiveFrom two Timers with frequency = 0.25 Hz to 1 MHz (in steps of 5 ns)

Channel Output pulse A to D

ParameterSpecification
Amplitude2 V to 5 V in steps of 10 mV
Load50 Ω
Rise/Fall Time< 1 ns / < 3 ns
Width100 ns to 10 µs, 5 ns resolution
Pulse PolarityPositive
Burst ModeFrom 1 to 2¹⁶-1
ConnectorBNC on the front panel

Clock IN

ParameterSpecification
Threshold0 V, internal 50 Ω
LevelMin -3 dBm
Frequency10 MHz (up to 100 MHz as an option)

Clock OUT

ParameterSpecification
Frequency10 or 100 MHz
Level+/-1 V into 50 Ω
ShapeSquare

Gate

ParameterSpecification
InputActive high, threshold 1.5 V, positive or negative slope
FunctionOutput inhibit (Global or individual channel)

T0 output

ParameterSpecification
Amplitude5 V / 50 Ω, 200 ns width
ConnectorBNC on the rear panel

General

ParameterSpecification
Interface ControlFront panel, USB to UART, Ethernet 10/100Mb/s
User memoryUp to 4 sets of parameters can be stored/recalled via the front panel, Ethernet, or USB
Software toolsFree Drivers for Windows 7/10
Power Supply90 to 240 VAC, 50 W
Weight<1 kg
Size215 x 245 x 135 mm

Option 8C: Auxiliary channels (E to H)

Delay channelChannel output pulse
Number: 4 independentsAmplitude: 2.5 to 5 V / 50 Ω, common tuning
Range: 0 to > 20 secondsWidth: 100 ns to 10 ms, 5 ns resolution
Resolution: 1.25 nsRise and fall time: <5 ns
Jitter: <50 ps RMS + delay x 10⁻⁸ (external trigger to any output)Connector: BNC on the front panel
Accuracy: 1 ns + delay x 10⁻⁸

Option CLK IN & out: Clock frequency

ParameterSpecification
Clock In or OutputUp to 100 MHz clock Input or Output (request when ordering from factory)

4Functional Overview

Model 745T block diagram showing the time base, trigger controller, four high-resolution delay channels, four optional auxiliary channels, channel outputs, and the interface controller with Ethernet and USB
Model 745T block diagram.

Timebase

The timebase is provided from an internal clock reference or an external 10 MHz clock (CLK IN). As an option, the external clock can be up to 100 MHz. The time base is available on the rear panel (CLOCK OUT).

Delay channel

There are four independent delay channels. The delay from the selected trigger source is adjustable up to 20 seconds in 1 ps increments.

Jitter: The following indicates typical RMS jitter at various delays:

Internal Trigger ModeExternal Trigger Mode
Delays < 100 ns: 5 psDelays < 100 ns: 5 ps
Delays > 100 ns: 15 ps + delay x 10⁻⁸Delays > 100 ns: 25 ps + delay x 10⁻⁸

Triggering

The Model 745T offers users several methods for triggering delay channels:

  • Externally trigger on the positive or negative slope of your trigger signal and selected level from 0.1 to 5.0 V.
  • Two frequency programmable Timers are adjustable from 0.25 Hz to 1 MHz in 1 Hz increments (5 ns).
  • Software trigger from remote command.

Trigger Modes

  • Burst mode: pulse number 1 to 2¹⁶-1, period 1000 ns to 1 second (depending on the trigger rate).
  • Trigger Pre-scaler: pre-scaler value applied to the external trigger goes from 1 to 2¹⁶-1.
  • Gate mode: can be set to global or individual channel.

Outputs

On the front panel, each delay channel output pulse is independently adjustable in level and width. The outputs are designed to drive an external 50 Ω load. T0 Output pulse is a time reference that marks zero delay.

Interface Control

All parameters may be locally controlled via touch screen or remotely controlled via Ethernet or USB. The Model 745T has an embedded control interface software that allows all parameters to be controlled by any PC with a browser.

5Trigger Modes & Examples

Repetitive and single trigger

Timing diagram of repetitive and single trigger: Channel A repetitive from Timer 1, Channel B repetitive from Timer 2, Channel C single from command, Channel D burst of two from Timer 2
Example of channel outputs: repetitive and single trigger. Channel A (repetitive from Timer n°1), Channel B (repetitive from Timer n°2), Channel C (single from command), Channel D (burst number = 2 from Timer n°2).

Prescaler and gate mode

Timing diagram of prescaler and gate mode: input trigger, Channel A from prescaler equal 4, gate on Channel B active high, Channel B from prescaler equal 4 and gate
Prescaler and gate mode. Channel A (from Prescaler = 4), Gate on Channel B (active high), Channel B (from Prescaler = 4 and Gate).

Pulse picking

Timing diagram of pulse picking: external clock at 80 MHz example, Channel A from Timer 1 with delay 0, Channel B from Timer 1 with delay, Channel C from Timer 2, Channel D pulse picking single shot from command
Pulse picking. External clock (80 MHz for example), Channel A (from Timer n°1 & delay = 0), Channel B (from Timer n°1 & delay), Channel C (from Timer n°2), Channel D = Pulse picking (single shot from command).

6Narrow Pulse Option

The narrow pulse option provides pulses up to 5 ns width, on the outputs T1 and T3. The value of width is adjustable in steps of 1 picosecond. The narrow pulse is achieved by mixing two outputs.

Oscilloscope capture of the narrow pulse option: T1 set to 10 ns in purple and T3 set to 5 ns in pink, at 5 ns per division and 2 V per division
T1 set to 10 ns (in purple) and T3 set to 5 ns (in pink). 5 ns/div and 2 V/div.

7Control & Software Tools

There are three ways to control the generator.

“Local way” via the touch screen

Model 745T touch screen main menu showing pulse output settings, internal frequencies, general settings, and trigger controls
Touch screen: main menu.

A three-level Menu is available:

  • A main menu displays settings.
  • Sub-Menus to select the parameter to set.
  • Keyboard to set the new parameter value.

“Easy remote way” via Internet and control panel web pages

Model 745T embedded web server setup page showing per-channel delay, amplitude, polarity, width, trigger settings, internal frequencies, burst mode, and external clock
Setup web page.

A web page, from an embedded Web server, provides a simple method to configure settings for each channel (delay, output amplitude, polarity, output width, trigger mode, trigger source), to control operation, and to display the status of the instrument.

The configuration information of the instrument is stored and saved in the Model 745T. The web page can be opened via Internet Explorer, Mozilla Firefox, or Google Chrome.

After connecting a cable from the Model 745T's Ethernet port to your computer network, enter the Model 745T's IP address into your PC's browser (the IP address can be identified or assigned via the front panel). The browser will automatically open the control panel web page on your PC.

“General remote way” via BNC software application or other PC software applications

The Model 745T can also be controlled by the BNC software application or by other PC software applications.

8Input / Output Interface

Front and Rear Panel

Model 745T front and rear panel diagrams with numbered callouts for the touch screen, gate input, run stop button, A to D outputs, E to H auxiliary outputs, trigger input, T0 output, AUX, Ethernet, USB, clock in, clock out, power switch, and AC plug
Front and rear panel connectors, switches, and indicators.
Front PanelRear Panel
1  Touch screen for local control7  T0 output, BNC connector
2  GATE input, BNC connector8  AUX, No function
3  RUN/STOP for single-shot triggers9  (Ethernet), RJ45 connector
4  A, B, C, D pulse outputs, BNC connector10  (USB interface), micro-USB connector
5  E, F, G, H auxiliary outputs, BNC connector11  Clock INput, BNC connector
6  TRIG input: BNC connector12  Clock OUTput, BNC connector
13  POWER ON/OFF switch
14  AC power plug (90-240 V)

9Ordering & Accessories

Ordering Information

ModelDescription
Model 745T-4CBase version: 4 high-resolution delay channels
Model 745T-8CAdds 4 auxiliary channels
Model 745T-XC-CLKUp to 100 MHz clock Input (or Output)
Model 745T-NRWAdds narrow pulse version
Model 745T-RM119” Rack-mount kit, Single unit
Model 745T-RM219” Rack-mount kit, Dual units
Model 745-OEMOEM version (board level) of the Model 745T

Accessories (pulse shaping modules)

ModelDescription
GFT101Electrical-to-optical, Pulse Converter
GFT63232 - 70 V, 3 ns rise time into 50 Ω, Pulse Generator
GFT6444 channel 50 Ω Line Driver Module