Model 745T User Manual

1General Information

The MOD745 device provides four high precision independent delay channels. Access to these four outputs (T1 to T4) is given by four BNC connectors on the front panel. The achieved delay resolution is about 0.25 ps, and trigger-to-channel jitter is less than 25 ps (Annex B). T1 to T4 can deliver up to 5 V, 2 ns rise time max (Annex A), into 50 Ω. Amplitude and width are adjustable on each output channel, either programmed from the front panel or via Ethernet.

A T0 output pulse is also available. It gives a time reference for each generated delayed output. This high accuracy and precision device is suitable for systems and experiments in science or industry that require a reliable timing solution.

The MOD745 also provides four optional delay channels at front panel T5 to T8, with a delay resolution of 1.25 ns, trigger-to-channel jitter less than 50 ps, and a common 2 to 5 V tunable amplitude. The internal timebase reference is a TCXO with a stability of 0.5 ppm. An optional OCXO with 50 ppb precision can replace the standard one.

The device offers three operating trigger modes: repetitive (internal or external source), single shot (internal, external or asynchronous source), and a burst mode (internal, external or asynchronous source). A web page accessed via the Ethernet link provides a simple method to configure the settings for each channel, amplitude, width, trigger source, and trigger mode, and to control operation. You can save and recall settings.

Instrument Options

Package Contents

The box you receive should contain the following:

• MOD745 Digital Delay Generator
• PDF user manual and LabVIEW VIs, available for download from the manufacturer support portal
• Certificate of calibration

For more information about BNC products, see our web site: www.berkeleynucleonics.com.

What You Need to Get Started

To set up and use the MOD745, you need the following items:

• MOD745 Digital Delay Generator
• MOD745 user manual

Unpacking Caution

Operating Temperature

The MOD745 can be operated where the ambient air temperature is 10°C to 35°C, and can be stored in ambient temperature from -10°C to +60°C. The MOD745 is cooled by air circulation.

Self-test

The unit model, firmware version, serial numbers, and the result of the self-test procedure are displayed one minute after power on. After 30 seconds, if the test is good, then "self-test" disappears and the device can be used. If the test is not OK, then "self-test" stays displayed and the device is locked.

The Device Software

LabVIEW VIs are provided with the MOD745 device. They allow users to control or configure the equipment as planned. These VIs can be integrated into a top-level VI where several devices are controlled. The communication is done with an Ethernet connection.

Power Fuses

The MOD745 is protected against short circuit by means of one fuse according to the nameplate of the power supply (F2.5H250V).

RAM with Battery Backup

The MOD745 has a RAM with battery backup in which settings of the instrument can be stored (Lithium battery ref 2032).

2Specifications

Delays

Trigger Source

Clock Input

User Memory

Up to 4 sets of MOD745 parameters can be stored and recalled via the front panel or Telnet.

General Specifications

Output T1 to T4 (A to D), BNC Connector

Options

745-8C: 4-auxiliary delay output extension. Output T5 to T8 (E to H):

Trigger Mode

• Trigger level, from 0.1 to 5 V; internal load 50 Ω
• Positive or negative slope
• Minimum trigger delay < 60 ns
• Single, repetitive, or burst

Burst Specifications

• Pulse number: 2 to 2¹⁶-1
• Period: 1000 ns to 1 s

Gate Mode

• 2 settings: General or Individual
• Gate source: active high, repetition rate < 100 kHz

Additional Options

• -C: Clock output (10 MHz, +/- 1 V, square)
• -G: Gate input
• -O: OCXO 50 ppb
• -USB: Serial communication via USB port

3Front Panel Overview

The Model 745 front panel is composed of several kinds of elements: the user interface, which consists of a keyboard and an LCD display that allows the user to program various settings and to interact with the device in local mode; 4 status LEDs; and BNC connectors.

LCD Screen

The screen is a 4.3" touch screen.

RUN/STOP Button

Global RUN/STOP. It enables the user to RUN or STOP all output channels.

BNCs

One input Trigger, one Gate input, and 4 independent output channels (A to D) are available. The output voltage is tunable from 2 to 5 V for each output independently, and each one has to be terminated in 50 Ω. The input Trigger BNC connector provides a trigger signal operating up to 50 kHz.

Optional BNC

The four optional outputs (E to H) connectors are 50 Ω impedance with adjustable amplitude, delay, and width.

4Rear Panel Overview

All optional output connectors and modules appear on that side of the device. The other features are listed below.

Power Switch

The unit is turned on by depressing the Power button. The MOD745 can be operated from 100 to 240 V at a line frequency of 50 to 60 Hz.

T0 Output

A reference pulse output is available. It delivers a fixed amplitude pulse with adjustable width. Terminated in 50 Ω.

Optional BNCs

Clock input and clock output connectors are available. The CLK IN connector accepts either a 10 MHz or 80 MHz (or custom) clock frequency. The optional clock output (CLK OUT) comes from the CLK IN connector or from the internal oscillator, if the clock in signal is not present. For now, the AUX connector is not used.

Ethernet Port

A RJ45 Ethernet connector is available to control the Model 745 with a computer. See Section 8.

USB Port (Option)

A female USB connector can be available, allowing serial communication with the MOD745. See Section 8, Programming, for command syntax.

5Menu Structure (Navigating the MOD745)

A three level menu is available:

• A main menu to display settings
• Sub-menus to select the parameter to set
• Keyboard to set the new parameter value

The following is a presentation of the display menu for an 8-channel unit. From the main menu (Figure 3), the user can access every MOD745 setting by pressing the selected parameter zone.

Main Display

Channel Settings

Internal Frequency Display

General Settings

External Trigger Settings

Burst Mode Settings

6Operating Information

Operating Principles

The principle of the programmable delay generator is described in the figure below.

The trigger source can be provided by the TRIG IN input, by an internal trigger, or by a software command trigger. Repetitive, single shot trigger, and burst modes are available with internal and external sources. An asynchronous single shot and burst mode are also available.

Repetitive Triggers

When the external trigger source is selected, a rising edge on TRIG IN starts a delay sequence. The sequence is depicted in Figure 12. A prescaler value can be used to divide the Trig Ext input signal frequency. To get this feature, the user has to select EXT as the trigger source on the device via the front panel or via remote control (web page, Ethernet link).

If the internal trigger source is selected, the user can specify the needed trigger source via the front panel or via remote control. Two frequency generators derived from the input clock can be used as repetitive triggers: IN1 and IN2, corresponding to programmable Frequency 1 and 2. The use of the internal trigger is depicted in Figure 14. Frequency generation restarts when a push on the ESC button is detected while the Frequency/Period menu is displayed.

Single Shot Triggers

Three single shot modes are available: one synchronous to the external source (SSE), one to an internal source (SS1 synchronous to Frequency 1, SS2 synchronous to Frequency 2), and the last an asynchronous one (LSS). Each single shot mode is triggered by a software command. The software trigger command is available either via remote control or via the front panel. Single shots synchronous to an external source are depicted in Figure 12. The same principle can be applied to any of the internal sources.

Burst Mode

The Burst mode is defined by its trigger source (internal, external, software/single shot, or repetitive), its pulse number in each burst, and the period between pulses. A pulse train can be independently set and defined on each channel: amplitude, width, and delay are defined in the corresponding channel menu. An example of Burst mode is depicted in Figure 15. To generate a burst on a specified channel, first the user has to configure the Burst mode itself (trigger, pulse number, and pulse period), and then select "Burst (BST)" in the trigger source selection of the concerned channel.

Output Channels

A T0 output pulse is the time reference of the delay output. It is generated for each selected trigger. Each output delayed pulse value, T1 to T4, can be independently tuned in level, absolute or relative delay, and width. All values (delay, delay reference, level, width, gate) are saved in memory except the trigger source. Each output delayed pulse value, T5 to T8, can be independently tuned in absolute or relative delay and width. All values (delay, delay reference, width) are saved in memory except the trigger source. Calibration parameters are saved onboard. After power on, all trigger sources are off. Note that several output channels can only be triggered by the same source, that is to say an internal OR external source.

Gate Mode

Each channel can be independently or simultaneously gated by the Gate In input signal. A Gate menu is available in the main menu of the MOD745 device and in each Tx sub-menu. Two different modes can be selected in the general Gate menu:

• A GENERAL mode to gate simultaneously all channels.
• A CHANNEL mode to gate independently each channel by setting in each Tx sub-menu the desired gate state ("1" active, "0" inactive).

Configuration Summary

Figure 11 presents a functional diagram of the device. The different operation modes are illustrated.

Timing Principle Using External Trigger

When the device is in a rest state (no current output signals), a rising edge on a trigger starts a delay sequence. The trigger comes from TRIG IN or from a software command trigger (depending on the selected channel source). The sequence includes two external trigger phases:

• After an insertion delay (< 60 ns), a pulse appears on each channel after a specified delay.
• At the end of the sequence, after the last delayed pulse, the delay generator is ready for repetitive trigger mode.

When a sequence is in progress, the instrument does not respond to a trigger event. The MOD745 must be configured (trigger, delay, etc.) before starting any sequences.

In response to an input pulse, the device can generate a single delayed output (single shot) or repetitive delayed output (repetitive mode with a Trig In prescaler value = 1). As explained before, the single shot pulse is conditioned by the soft trigger command. The use of the prescaler value is depicted in Figure 13. The T1 channel trigger source is set to external trigger.

Timing Principle Using Internal Trigger

In internal trigger mode, two tunable frequencies are available (IN1 and IN2). In Figure 14, the T1 output uses the IN1 trigger with a specified delay of 0 ps, and the T2 output uses the IN2 trigger with a non-null delay. The MOD745 must be configured (trigger, delay, etc.) before starting any sequences. The individual Channel Gate Mode is also depicted in Figure 14. It is obtained by setting general Gate Mode to "CHANNEL" and T1 Gate mode to "ON". The result is that the Gate In signal allows the pulse output of the channel T1.

The width parameter does not appear in Figures 12 and 14. Note that the frequency f used as the repetitive input trigger (internal or external) and the maximum width of a corresponding output channel TX are linked by:

Max Width TX = 1 / (4f)

Timing Principle Using Burst Mode

Each channel can be independently set to Burst mode. In the following example, the Burst trigger has been set to IN1, the Burst pulse number to 5, and the Burst period to TB.

The minimal burst period value is 1000 ns. Note that this value depends on the Burst trigger period value and on the Burst pulse number:

TB min = T trigger min / Pulse Nbr

So, to get a TB min = 1000 ns, we can configure the device as follows:

• Pulse nbr max = 5
• T trigger min = 5000 ns

As depicted in Figure 15, in the case of a generation of a pulse train (Burst Mode) on a channel, the Gate In signal can allow some pulses among the pulse train. Note that when a delay D is specified on a channel using Burst mode as the trigger mode, the MOD745 manages the delay generation according to that rule:

• If delay D > TB - 15 ns, the delay generation is shared between the delay register specific to the channel (Dchan = TB - 15 ns) and the delay register associated to the burst trigger generation (DBST = D - TB + 15 ns).
• If delay D ≤ TB - 15 ns, the delay generation is managed as usual, that is to say by using the selected channel delay register.

To summarize: D = Dchan + DBST when D > TB - 15 ns. When several channels are using Burst mode as the trigger mode and one of the specified delays leads to the DBST register use (D > TB - 15 ns), the DBST value will be ignored (each channel will be delayed by DBST).

7Operating Example

Default Values

These values are stored by default:

Initial Setup

Turn on the Model 745 with the rear panel power switch. After 30 seconds, the following information is displayed:

MOD745 · Sn xxxxx,4 V1 · SELF TEST

Setting Up the Instrument (Recurrent Mode)

The aim is to set a repetitive frequency of 1000 Hz to output pulse T1 (A), with an amplitude of 4 V and a width of 1 µs. Use the touch screen to configure the settings as follows:

• Go to the internal frequency display.
• Set Freq 1 to 1000 Hz and return to the main menu.
• Go to the channel setting display and select channel T1 (or A).
• Set amplitude to 4 V and width to 1 µs.
• Select IN1 as the trigger source.

As soon as T1 (A) is set to IN1, the main display LED of T1 (A) will be on, indicating that there is an output signal on the T1 (A) connector. With an oscilloscope you can check the channel T1 (A). The measurement should be a rectangular shape with repetitive frequency = 1000 Hz, amplitude = 4.0 V, width = 1.0 µs.

Setting Up the Instrument (Single Shot Mode)

The procedure explained before can be followed up to the trigger choice. Three single shot modes can be set (external: SSEXT; internal: SS1 and SS2; asynchronous: LSS). Once the single shot trigger mode is set, the user has to send a software command to trigger the single shot output pulse. To send this software command, three ways are available:

• Via the front panel: in the general menu, by pressing the TRIG button.
• Via a Telnet command, by sending the RUN command to the device.
• Via the web page, by pressing the manual trigger button in the Trigger menu.

Setting Up the Instrument (Burst Mode)

The aim is to set channel T1 (A) in Burst mode to get:

• A 5 V, 200 ns width, 0 ns delay pulse
• 100 Hz IN1 trigger source
• Burst period 100000 ns, pulse number = 10

First the user has to configure the F1 frequency to 100 Hz and then the Burst Mode itself. That is to say, set in the Burst Mode menu:

• Burst Trigger: IN1
• Burst Period: 100000
• Burst pulse number: 10

Once this has been done, the user has to set the width, delay, and trigger source (BURST) in the T1 channel sub-menu. The device will start to generate the requested pulse train.

Stop the Generator

To stop the generation of that repetitive pulse, you have to set the T1 trigger to the OFF value. This will switch off the corresponding LED. With an oscilloscope you can check if the output signal is switched off.

8Programming

Serial Communication (USB Port)

To access the MOD745 via the USB port, you have to configure the connection as follows:

Ethernet Connection and Communication

For connection over a LAN, you have to do the following:

• Connect the instrument to the LAN physically.
• In the graphical user interface, specify the LAN address.
• On the control PC, enter the instrument's IP address.

After the connection has been established, the following commands can be used to modify the settings:

• Set the instrument's IP address with: IP XXX.XXX.XXX.XXX
• Query the instrument's IP address with: IP? returns :IP XXX.XXX.XXX.XXX
• Set the instrument's IP mask with: NM XXX.XXX.XXX.XXX
• Query the instrument's IP mask with: NM? returns :NM XXX.XXX.XXX.XXX
• Set the instrument's IP gateway: GW XXX.XXX.XXX.XXX
• Query the instrument's IP gateway with: GW? returns :GW XXX.XXX.XXX.XXX

About Telnet Ports

Three ports can be used to configure the communication link and/or the microcontroller used to communicate:

Command Structure (Ethernet and USB Connection)

Each command description is composed of at least some of the following items (all commands are used in a Telnet prompt): full command syntax, form (Set / Query), brief description, parameters, RST value, specified limits, and example.

*IDN?

BURST TRIG

BURST PULSE PERIOD

BURST PULSE NUMBER

GENERAL GATE MODE

CHANNEL GATE MODE

RELATIVE DELAY

ABSOLUTE DELAY

TRIG

AMPLITUDE

WIDTH

EXT TRIG THRESHOLD

EXT TRIG POLARITY

EXT TRIG PRESCALER

FREQUENCY

PERIOD

CLKEXT

RUN

STORE

RECALL

STAT

IP ADDRESS

NET MASK ADDRESS

GW ADDRESS

Web Page Control and Communication

The user can open a web page to control the MOD745 device via Internet Explorer, Firefox, or Chrome (last versions supported). To access the web page, the IP address of the device has to be typed in the navigator address field. Once that is done, the user should reach the following page.

From that page, the user can configure each output pulse (amplitude, width, trigger, delay, inhibit, and delay reference), trigger settings, internal frequencies, external clock, and burst mode. On the first setting change, the user will be asked for a login and password (default login: BNC; default password: bnc). Status LEDs indicate which outputs are active or not, and Fault LEDs warn the user in case of errors. To refresh LED status, the user has to click on one of these LEDs. The manual trigger button is used to trigger a channel set to SS1, SS2, or LSS (single shot 1 and 2, and local single shot). Finally, the user can access the password setting page by typing in the address field: "Device IP/passwd.htm".

9Annex A: Pulse Results

High precision and auxiliary pulse results appear on the following figures.

10Annex B: Delay Jitter

The RMS jitter for internal and external sources is depicted in the following figures. It is given for different delay values.

11Compliance and Contact

BNC Product Information for the People's Republic of China

This document provides product information as required by the People's Republic of China Electronic Industry Standard SJ/T11364-2006, Marking for Control of Pollution Caused by Electronic Information Products. The table below lists toxic or hazardous substances or elements contained in electronic information products (EIPs), including subassemblies, that exceed limits specified in SJ/T11363-2006.

O: Indicates that the toxic or hazardous substance contained in all of the homogeneous materials for this part is below the limit required in SJ/T 11363-2006. X: Indicates that the toxic or hazardous substance contained in at least one of the homogeneous materials used for this part is above the limit requirement in SJ/T 11363-2006.

In accordance with the requirements specified in SJ/T 11324-2006, all BNC EIPs sold in the People's Republic of China are marked with a pollution control marking. The environmentally friendly use period (EFUP) is the number of years from the date of manufacture that toxic or hazardous substances or elements contained in EIPs will not leak or mutate under the normal operating conditions described in the EIP user documentation. Manufacture dates of all BNC products are encoded into the product serial number. Contact your local sales office to obtain the manufacture date for your product.

Waste Electrical and Electronic Equipment (WEEE)

EU customers: at the end of the product life cycle, all products must be sent to a WEEE recycling center.

Support

Berkeley Nucleonics Corporation
2955 Kerner Blvd., San Rafael, CA 94901
Phone: (415) 453-9955
Email: info@berkeleynucleonics.com
Web: www.berkeleynucleonics.com

Model 745T User Manual · NUT 083, Ed. 1.0 · Print Code: 41025070