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.

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+¶

The signal source can be either AC or DC coupled:

DC coupled signal sourceAC coupled signal source

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

OPX+OPX

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.

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.

Multi-OPX connectivity versionSingle OPX version

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.

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