• Model 745T
  • Model 745T
  • Model 745T
  • Model 745T
  • Model 745T
  • Model 745T
  • Model 745T
  • Model 745T
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The Model 745T Digital Delay Generator (DDG) offers the world's leading performance in a benchtop timing instrument. 25 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 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 a new “Web-Command” interface embedded in the unit itself. 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 with a browser. You will need to enter the unit's IP address into the browser after connecting a cable from the Ethernet port to your computer network. The instrument will provide an IP address on the front panel display and the browser will open a virtual control panel. This is ideal for laboratories where you may need to move the delay generator to different locations. See our video on Browser-Based Instrument Controls.

Overview

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 < 100ns: 2 picoseconds
  • Internal Trigger, Delays > 100ns: 15 picoseconds + timebase
  • External Trigger, Delays < 100ns: 25 picoseconds
  • External Trigger, Delays > 100ns: 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.lV to 5.0V. 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 5ns as well, the range is then 1µs to 4s by step of 5ns). 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 2^16-1, period 1000ns to 1s (depending on the trigger rate)

TRIGGER PRESCALER, for instance: prescaler value applied to the external trigger goes from 1 to 2^16-1

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.

Ordering Instructions -

Order according to the following chart -

Model Number Description
745T-4C Standard Touchscreen Model, 4 Precision Channels
745T-8C Standard Touchscreen Model, 4 Precision Channels, 4 Additional Channels
745-RM Rack Mount, accommodates 1ea or 2ea Model 745T units
Add GFT101 module Electrical to Optical output
Add GFT500 module (fast rise time) 200ps Step Generator Module
Add GFT200 module Optical to Fast Electrical Pulse of 10 volts under 50Ω
Add P/N 7130 module Output pulse 32V amplitude under 50Ω, < 3ns rise time
Add GFT400 module 2V under 50 Ω, narrow 500ps width pulses

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. Available with GFT400 Module.

Specifications

Delays

Channels4 or 8 independent delay outputs
Range0 up to 20s
Resolution1 ps
RMS Jitter25 ps + delay x 10-8(T0 to any output)
Accuracy< 250 ps + delay x 10-8
Time Base50 ppm stability

 

Trigger source (repetitive / shots / burst)

InternalTwo Timers, F= 0.25 Hz to 1 MHz
External

1 trigger input

Software Asynchronous single shot

Output T0 5 V / >50 Ω, 100ns to 10µs

Posititve or negative slope

Minimum trigger delay < 65 ns

CommandFront panet / Ethernet / USB

 

Outputs T1 to T4

Amplitude2 V to 5 V / 50 Ohms
Rise/Fall time5 ns/ 5 ns
Width100 ns to 10µs
ConnectorBNC
Clock Input (1)10 MHz or 80 MHzAsk factory for custom clock frequency

General

Interface Control Front panel, Ethernet/

Internet (Webpage)

Software Free Drivers for Win7
Size Rack 19", 2U, D= 300mm
Power 90 to 220 V / 0.5 A

Linecard

AttachmentSize
PDF icon DDG Line Card618.64 KB

Datasheet

AttachmentSize
PDF icon Model 745T Datasheet302.23 KB

Technical resources

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