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OPX & OPX+ Hardware Specifications

This page describes the hardware components of the OPX & OPX+.

Technical specifications

The table below groups the main characteristics of the OPX & OPX+ .

Property Value
Input Voltage 100-240 V, 50-60 Hz
Power specifications 300 W
Dimensions (width, depth, height) 44.4 x 49.9 x 8.8 cm
Rack Dimensions 19 inch, 2U
Operational Temperature Range 0-40 degC

Port specifications

The table below groups the main characteristics of the OPX & OPX+ ports.

OPX ports Analog outputs Analog inputs Digital outputs External trigger
Voltage settings ±0.5 V or 4 dBm ±0.5 V or 4 dBm 3.3 V (LVTTL) 3.3V (LVTTL)
Bandwidth ±350 MHz ±350 MHz pulse width > 2ns pulse width > 4ns
Resolution 16 bit DAC 12 bit ADC 1 bit 1 bit
Impedance 50 Ω 50 Ω High Z High Z

Note

If the external trigger requires a low impedance port, its is advised to add a 50 \(\Omega\) terminator to the line. See Guide on External Triggering for more details regarding the usage of external triggering in the OPX.

OPX+ Block Diagram

The simplified block diagram model for the OPX+ can be seen below.

OPX+_Block_Diagram

Analog Input Stage

The signals acquired by the OPX using the analog input channels are first passed through an analog input stage and then digitized. Here we discuss the voltage limits, gain and offset calibrations that can be applied to the signal to be digitized.

Acquiring analog signals with the OPX & OPX+

analog_input

The signal source can be either AC or DC coupled:

If the signal source is DC coupled and has 50ohm DC resistance to ground, it can be directly connected to the analog input. This can be seen in Option 1 of Fig. 1

If the signal source is AC coupled and does not have a 50ohm resistance to ground, a bias T is needed in order to bias the input amplifier. The required setup can be seen in option 2 of Fig. 1. In this case, the source will still need to have a 50ohm AC impedance throughout its bandwidth for proper operation.

Important

The OPX & OPX+ input has a common-mode voltage of 0.25V when measured with 50ohm.

Setting the voltage gain

The voltage gain can be set by adding a "gain_db" field to the "analog_inputs" field of the controller in the config. It can take integer values between -12 dB to 20 dB. Here we show an example with the relevant fields:

config = {
    'version': 1,
    'controllers': {
        'con1': {
            'analog_inputs': {
                1: {'offset': 0.0, 'gain_db': -1},
                2: {'offset': 0.0, 'gain_db': 1},
            }
        }
    },
}

Warning

When the gain is set to max attenuation, -12dB, the maximal power that can be input to the ADC without significant distortion is 16dBm or 4Vpp.

Please avoid exceeding 4dBm (1Vpp) without attenuation. This may damage the controller.

Note

When changing the gain, the input DC offset needs to be recalibrated.

Back Panel Description

The back panel of the OPX is the interface for control, power and connectivity to other devices. The following section details the back panel of the OPX and the OPX+ controllers. Click on the relavnt

Important

Some early back panels might have different labels. These which might appear different are marked with an astrix. The correct labels are the ones shown on this page.

OPXp_back_panel

Back Panel Description

Number Label Description
1 LAN LAN port for network connection to router
2 Ground symbol Chassis earth ground
3 OPC Com. Inter-OPX optical connectivity (for a multi-OPX system)
4 Reset Factory reset (currently disabled)
5 nan 2 USB ports
6 Clock in External clock reference (10,100,1000 MHz)
7 100GBE Not in use
8 Sync Sync from OPT (for a multi-OPX system)
9 Ext. trig (3.3V)* External trigger
10 Digital Ext. Connection for OPD - digital input/output extension
11 AUX 1 (1.8V)* QSync
12 AUX 2 (1.8V)* QSync
13 Line Power inlet and switch

The OPX has several back panel versions. Click on the toggle keys to view them.

OPX_back_panel

Back Panel Description

Number Label Description
1 PCIe Connection to the server
2 Ext1 Not in use
3 Ext2 Not in use
4 USB 2 USB 3.0 ports. Server connects to the lower one
5 LAN Not in use
6 Inter OPX communication 10 optical ports for fast communication between OPX's
7 External clock External clock reference (10,100,1000 MHz)
8 Sync Synchornization with the OPT
9 Aux1 External trigger input
10 Aux 2 Not in use
11 Line Power inlet and switch

Important

Some early back panels might have different labels. However, the correct labels are the ones shown on this page.

OPX_back_panel_noGT

Back Panel Description

Number Label Description
1 PCIe Connection to the server
2 Ext1 Not in use
3 Ext2 Not in use
4 USB 2 USB 3.0 ports. Server connects to the lower one
5 LAN Not in use
6 Aux1 External trigger input
7 Aux2 Not in use
8 External clocl External clock reference (10,100,1000 MHz)
9 Sync Not in use
10 Line Power inlet and switch