Model 745T

Model 745T | 1 ps Delay ResolutionFemtosecond Digital Delays with 5 Picosecond Jitter

The Model 745T Digital Delay Generator (DDG) offers the world's leading performance in a benchtop timing instrument. Twenty-five years ago, our Model 7095 Digital Delay Generator dramatically advanced research with jitter below 25 ps. Now, with all the features of a modern DDG, the Model 745T gives users incredible performance at a fraction of the cost. The Model 745T offers 4 precision delay channels from the front panel (output rise time less than 2 ns) with an additional 4-channel option on the rear panel (output rise time less than 5 ns). The Model 745T synchronizes to an external clock at 10 MHz or 80 MHz or custom frequency between 10 MHz and 80 MHz making the unit ideal for a broad range of applications that require short time domain delays.

The Clock In Connector and Clock Out Connector, are located on the rear panel of the instrument. A convenient Ethernet interface on the rear panel, allows remote control of the instrument. Berkeley Nucleonics' DDG-MUC software controls up to eight instruments (64 Channels). Alternatively, you may use the LabVIEW driver or the embedded web interface for ease of set up and control. The control software and LabVIEW drivers are included with the Model 745T at no additional cost.

Because many industries are now moving away from locally installed software packages, we have embedded a control interface in the Model 745T instrument. This also allows all parameters to be controlled by any PC, Mac or Linux system with a web browser. All you have to do is type in the unit's IP address into the browser after connecting a cable from the Ethernet port to your computer or network. A USB port is also available if LAN port cannot be used. Ethernet ports allow the user to use the web interface or sends and receives SCPI commands while the USB is SCPI . This is ideal for laboratories where you may need to move the delay generator to different locations.

Overview

Overview 

Quick Specs

Applications

  • Channels: 4 or 8 Independent Channels
  • Resolution: 1 ps 
  • Accuracy: < 250 ps + delay x 10e-7
  • Jitter: 25 ps + Delay x 10e-8 (External Trigger to any output)
  • Voltage: 2 to 5 V, step < 0.1 V / 50 Ω
  • Memory: 12 Memory Storage Slots
  • Femtosecond Resolution
  • ATE Applications
  • Large Laser System Timing Control
  • High Precision Timing
  • Components Testing/QC
Jitter

The Model 745T virtually eliminates triggering indeterminacy by having a clock that is now in phase with an External Trigger. The resulting external trigger jitter is far better than instruments whose outputs are synched to an internal free-running clock. See the datasheet for exact jitter specification and additional details on "Achieving 2 Picoseconds Jitter in a DDG". The following chart indicates typical jitter at various delays:

  • Internal Trigger, Delays < 100 ns: 2 picoseconds
  • Internal Trigger, Delays > 100 ns: 15 picoseconds + timebase
  • External Trigger, Delays < 100 ns: 25 picoseconds
  • External Trigger, Delays > 100 ns: 25 picoseconds + timebase

Back of Model 745T

Triggering

The Model 745T Digital Delay Generator offers users several options for triggering timing channels: External, Internal, and Remotely (Remote trigger: only asynchronous Single-Shot). Externally trigger on the positive or negative slope of your trigger signal and select a level from 0.1 V to 5.0 V. Two internal trigger generators are adjustable from 0.25 Hz to 1 MHz in 1 Hz increments (note: it's possible to set the period by step of 5 ns as well, the range is then 1 µs to 4 s by step of 5 ns). These internal rep rate generators may be started by front panel pushbutton or remotely via your software interface. Either trigger mode may be set as one-shot or repetitive.

BURST MODE, for instance: pulse number 2 to 216-1, period 1000 ns to 1 s (depending on the trigger rate)

TRIGGER PRESCALER, for instance: prescaler value applied to the external trigger goes from 1 to 216-1

GATE MODE, for instance: can be set to General or individual channel

*See the user manual for more details.

Packaging

The Model 745T Digital Delay Generator is housed in a compact design. The packaging dimensions are of 8.5" X 9.6" x 5.3". The convenient design allows two instruments (up to 16 channels) to fit side-by-side in a 19" rack mount (sold separately). This small footprint allows for many channels packed into a small space on a bench or in a rack system. Berkeley Nucleonics offers a variety of custom packaging options as well. For even tighter space constraints, ask about a cPCI card-level version of the Model 745T or a custom enclosure design. Multi-instrument applications may find that operating from a single master clock may be useful. The standard benchtop package can be mounted with one or two instruments in a 19" rack.

Outputs

On the front panel there are four standard Outputs, one external Trigger Input, and one Gate Input. Optionally, four more Outputs can be available on the front panel as well (total eight channel outputs) On the rear panel, there are Clock In, Clock Out, T0, and Auxiliary connectors.

Optional Channel Feature -- Channel Grouping

Rise times below 1 nanosecond and Pulse Widths down to 10 nanoseconds are achieved by Channel Grouping. In this example, we group Channel 1 + Channel 2. The jitter is below 5 picoseconds and the delay and width resolution are both 250 femtoseconds. Contact the customer support for special output requirements.

Trigger source (repetitive / shots / burst)
Internal Rate Generator Two Independent Timers, 0.25 Hz to 1 MHz
External Trigger 1 Trigger Input

Positive or Negative slope

Minimum trigger delay < 65 ns

Software Asynchronous Single Shot

Control Front Panel or Remote (Ethernet or USB)
Clock Input Standard 10 MHz and 80 MHz     *contact factory for custom clock input frequency
Outputs
Number of Outputs Four (A to D) plus T0 [Standard]
Eight (A to H) plus T0 *OPTIONAL
Amplitude T0: 5 V into 50 Ω [Fixed]
A to D: 2 V to 5 V into 50 Ω [Adjustable]
E to H: 2 V to 5 V into 50 Ω [Adjustable] *OPTIONAL
Transition Time
 
Rise: < 2 ns 
Fall: < 2 ns
Pulse Width T0: 100 ns to 100 µs
A to D: 100 ns to 100 µs
E to H: 10 ns to 25 us  *OPTIONAL
Delay Range 0 ps to 20 seconds
Delay Resolution A to D: 1 ps
E to H: 1 ns
RMS Jitter 25 ps + delay x 10e-8 (T0 to any output)
Accuracy < 250 ps + delay x 10e-8
Clock Output 10 MHz [Square ~ +7 dBm]
Time Base 0.05 ppm stability 
Connector BNC
General
Interface Control Front-panel, LAN ( Internal Webpage or SCPI)
Software Web Browser (Firefox, Chrome, Internet Explorer)
Size Rack 19", 2U, D = 300 mm
Power 90 to 220 VAC / 0.5 A
Specifications 
Shippping Dimensions 22x9x17"
Shipping Weight 20 lbs
Options 
Model Number Description
745T-4C Standard Touchscreen Model, 4 High Precision Channels
745T-8C Standard Touchscreen Model, 4 High Precision Channels, 4 Standard Channels
745-RM Rack Mount System. Accommodates one or two Model 745T units
GFT101 Electrical to Optical Converter - Takes a 2.5 V to 10 V input and produces a 1310 nm output with 1 ns risetime and 30 ps RMS jitter. The converter connects to the front panel of the Pulse/Digital Delay Generator. The optical pulse is appx 0.3 mW and allows long-range transmission in remote locations. 
GFT200 Optical to Fast Electrical Pulse of 10 volts under 50 Ω - This unit takes 1310 nm wavelength pulses at -15 dBm or better, and converts them to 10 V output pulses with 30 ps RMS jitter. This unit enables long-range transmission of timing signals. 
GFT632 High Voltage Module - Offers fast output pulse 32 V amplitude under 50 Ω, < 3 ns rise time - This module is externally triggered and provides high voltage pulses with fast rise times. The device can be up to 20 meters from your pulse generator so it is closer to the device being triggered. A 70 V option is also available with widths of 1us and a rise time of 1.2 nanoseconds. 
Technical resources 
Downloadable Resources 

Downloadable resources such as datasheets, firmware, software, drivers and products manuals. Alternatively, you can browse resources directly by visiting our downloads page.

Product Datasheets
Product Firmware
Product Software and Drivers
Product Manuals

Media

Media 
Video URL 
Video URL 
Video title 
Model 745 Femtosecond Front Panel Controls
Video URL 
Video title 
Diplaying Dual Frequencies with the Model 745
Video URL 
Video title 
BNC Pulse Generator Output Modules - Overview
Video URL 
Video title 
Webinar on Fast Pulse/Low Jitter Timing Solutions

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