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Gemini-V6 (1 or 2 12-bit ADC, 1 12-bit DAC)
  • Overview
  • Features & Benefits
  • Details
  • Performance Specifications


The QuiXilica Gemini-V6 VXS is a 6U VME and ANSI / VITA 41 (VXS) compliant high-speed digitizer board that combines high density FPGA processing with the latest 12-bit ADC and DAC technology.  The Gemini-V6 supports either one 12-bit input channel at 3.6 GSPS or three input channels at 1.8 GSPS, combined with a high speed output channel at up to 4.0 GSPS.

QuiXilica Gemini-V6 VME / VXS
1 x 3.6 GSPS x 12-bit ADC or
3 x 1.8 GSPS x 12-bit ADC or
1 x 4.0 GSPS x 12-bit DAC

By employing three Xilinx Virtex-6 FPGAs, Tekmicro’s Gemini-V6 combines high resolution wideband signal acquisition and generation with the onboard high density FPGA processing for a range of radar and Electronic Warfare applications such as target generation, jamming, and CM / CCM techniques. The result is a single slot solution that utilizes the latest ADC and DAC technology, supports advanced signal processing of up to 8+ GB/s of digitized data, and forwards the results through VME, VXS or front panel connection via SFP+ or CXP to the next processing stage.

Sample accurate synchronization of ADC sampling and DAC outputs on a single board, and between multiple boards, is done using an external trigger signal.  This offers significant advantages in terms of channel matching performance for a range of advanced processing algorithms including multi-channel algorithms found in applications such as direction finding, Space Time Adaptive Processing (STAP) radar, EW, ELINT and Synthetic Aperture Radar (SAR) image formation.

The Gemini-V6 features high bandwidth, low latency interconnect paths between its FPGAs. These have been carefully specified to ensure that data from all ADC inputs can be combined and processed and then used to generate an appropriate DAC output.

The Gemini-V6 is available for a wide range of operating environments including commercial grade, rugged air cooled, and conduction cooled to support deployed applications such as unmanned airborne, naval and ground vehicles.  For more details, see Tekmicro’s Ruggedization Data Sheet.

In addition to Gemini-V6, Tekmicro offers a broad range of Xilinx Virtex-6 based streaming I/O and FPGA processing solutions for both analog and digital I/O in a range of form factors.



One 12-bit ADC channels at 3.6 GSPS, or three channels at 1.8 GSPS

Fastest 12-bit sampling in a COTS product and best available solution for 1st and 2nd Nyquist sampling with 900 MHz staring bandwidth

Combines ADC with DAC output channel at up to 4.0 GSPS

Integrated solution for signal digitization and generation with low latency FPGA processing and DRFM buffering

Independent or common clock inputs for ADC and DAC

Simplifies external clock distribution in many applications

Sample-accurate trigger input

Supports coherent processing of a large number of channels across multiple cards

Twelve fiber optic interfaces running at up to 6.4 Gb/s using CXP front panel connection

Flexible data movement across the front panel for use in standard VME environments

One SFP port for Gigabit Ethernet connectivity

Network access and data movement to FPGA's via on-board Gigabit Ethernet switch

Dual 4x full duplex VXS links and 2 full duplex VITA 41.6 ethernet links

Enhanced VXS capability

Three large pin count (1759 pin package) Xilinx Virtex®-6 devices available per board (LX240, SX315, or SX475). other configurations available

Matched FPGA processing and analog data bandwidth for dense channel count systems

5 GB DDR3 SDRAM Memory

Large memory resources for application flexibility

Two fully independent banks of (72 Mb/bank) QDRII+ memory on backend PFGA  

Advanced temperature and current monitoring

Protection from damage and usable in customer applications

Comprehensive developer’s kit provided including FPGA interface cores, QuiXstart FPGA utilities, software and reference designs

Faster application development

Convection or conduction cooled options

Ruggedization designed in for demanding deployed applications


The Gemini-V6 contains two ADC12D1800RF dual 12-bit 1.8 GSPS ADCs from Texas Instruments.  One ADC device is used for analog input only, and one is used for analog and trigger inputs.  Each ADC device is configurable as either a single channel of 3.6 GSPS digitization or two channels of 1.8 GSPS digitization, resulting in support of either one analog input at 3.6 GSPS or three analog inputs at 1.8 GSPS.  The analog inputs are single-ended, AC coupled into 50 Ω.   


The Gemini-V6 contains one MD653D 12-bit 4.0 GSPS DAC from Euvis.  The DAC may be operated in Normal Hold or Return To Zero mode and has a 4 GHz full power bandwidth.  The analog output may be configured as either single-ended or differential as a build option with a full scale output of -4 dBm into 50 Ω. 

Virtex-6 FPGAs

Xilinx Virtex-6 FPGAs are the heart of the Gemini-V6. The FPGAs interface between the ADCs, memory, DACs and I/O resources to provide a platform for implementing high performance real time processing. The Gemini-V6 is configured with three high pin count Xilinx Virtex-6 devices (LX240, SX315 or SX475) per board. Other device types can be used optionally or mixed for custom configurations. All FPGAs are interconnected by wide parallel LVDS busses and via high speed Aurora serial links using the Xilinx GTX transceivers. 

Front Panel High Speed Serial I/O

One 12-fiber CXP site is provided on the front panel for standard protocols such as Gigabit Ethernet or Serial FPDP (ANSI / VITA 17.1 & 17).  CXP modules and breakout cables are optionally available for flexible I/O capability. 

Onboard Gigabit Ethernet Networking and Switching

An onboard Gigabit Ethernet Switch connected to each FPGA supports routing of control plane signaling and minimizes FPGA involvement for data distribution/forwarding between FPGAs. A dedicated SFP port which supports both fiber and copper 1000 baseT ethernet connections is available to connect to an outside network.

VXS Backplane High Speed Serial I/O

The Gemini-V6 can be used as a VITA 41.0 payload card. Up to eight high speed serial links of up to 3.125 Gb/s full duplex data rates are supported via the VITA 41.0 MultiGig RT2 P0 connector. Custom or standard communication protocols can be run over these links by providing appropriate firmware in the FPGA. 

High Speed Parallel LVDS Interconnectivity 

All FPGAs are also interconnected with a number of LVDS pairs for optimized data transfer as the block diagram shows. 

QuiXstart FPGA Configuration

A number of options are available for configuring the FPGA on the Gemini-V6. A JTAG connection is available to allow users to configure the FPGA via standard Xilinx development tools. Onboard flash memory is available and can configure the FPGA on power up. Tekmicro’s QuiXstart tool supports flexible configuration of the FPGA through a Gigabit Ethernet link from a remote server after a power up or reset event. 


Two Trigger inputs are provided on the front panel to allow the hardware to be employed in a variety of radar and electronic warfare scenarios. Each trigger input is differential, supporting LVDS and LVPECL (as a build option).  One trigger input is used for the ADC channels and the other is used for the DAC channel.   The triggers are sampled at the ADC and DAC clock rates, respectively, providing sample-accurate synchronization both within a single Gemini-V6 card and across multiple cards in a system. 


Two sample clock inputs are provided on the front panel, one for the ADC inputs and one for the DAC output.  The input clock frequency for the ADCs is one-half the sample rate in the interleaved mode and equal to the sample rate in non-interleaved mode, resulting in a maximum ADC input clock frequency of 1.8 GHz in all modes.  The ADC and DAC clock input has a minimum level of -6.0 dBm input into 50 Ω. 


The Gemini-V6 has two independent banks of onboard DDR3 SDRAM for each FPGA.  The front end FPGAs have two 1 GB banks, each with throughput of 6.4 GB/s, while the back end FPGA has two 512 MB banks, each with throughput of 3.2 GB/s.  The total memory capacity is 5 GB with aggregate throughput of 32 GB/s across six banks.  All DDR3 memory banks are clocked at 400 MHz for an 800 MT/s transfer rate. In addition, there are two fully independent banks of QDRII+ SRAM memory for the back end FPGA. Each QDRII+ device has a 72 Mbit capacity (144 Mbit total) supported by an 18-bit data bus per bank. 

GPIO Connections

For general purpose I/O signals, the Gemini-V6 can be accessed via the P2 connector and there is also an SSMC connector on the front panel which can be used for such things as a GPS signal, etc. 

System Monitoring / Damage Protection

The Gemini-V6 includes facilities to monitor current and temperature at various points on the board. Current monitoring of all main power rails is available through the use of a Spartan-6 FPGA.  Die temperature monitoring of the three FPGAs and temperature monitoring of three locations on the PCB is also available. This allows a first level of protection when the Gemini-V6 is operating in different environmental scenarios. The output from the sensors is available to the user’s FPGA firmware applications, to allow the application to adapt to changes in environmental conditions. The Gemini-V6 also uses the system monitoring sensors to implement a system protection mechanism which will, independently of the user’s application, prevent excessive current or temperature from damaging the board. 

A/D Converter

Quantity: 1 or 3 channels
Sampling Rate: up to 1.8 GSPS (3 channel mode)
3.6 GSPS (1 channel mode)
Resolution: 12-bits
Type:  Texas Instruments ADC12D1800RF
Bandwidth: Up to 2.7 GHz
Connector:  SSMC
Type: Single ended, AC coupled into 50 ?, 2.0 dBm full scale 

D/A Converter

Quantity: 1 channel
Sampling Rate: up to 4.0 GSPS
Resolution: 12-bits
Type:  Euvis M653D
Bandwidth: Up to 4.0 GHz
Connector: SMA
Type: Single ended (differential as a build option), -4.0 dBm full scale 

Front Panel Trigger Inputs

Quantity: 2 via 4 SSMC Connectors
Type: 100 Ω differentially terminated, support for LVDS and LVPECL (build option)
Mode: Independent or common using ADC clock input 


Quantity: SSMC Connectors (ADC), SMA Connector (DAC)
Type: Single ended 50Ω terminated
Input Power Range (ADC): -6.0 dBm (min) to +14.0 dBm (max)
Input Power Range (DAC): +6.0 dBm (min) to +10.0 dBm (max)
Operating Modes: Independent or common using ADC clock input 

Network Interface

Front panel SFP for fiber or copper Gigabit Ethernet
VITA 41.6 P0 interface for 1000 BASE-KX Gigabit Ethernet
Onboard Gigabit Ethernet switch


DDR3 SDRAM (2 fully independent banks per FPGA)
Size: 1 GB per front end bank, 512 MB per back end bank
Bus Width: 64-bits per front end bank, 32-bits per back end bank
Speed: 400 MHz clock rate, 800 MT/s 

QDR II+ SRAM (2 fully independent banks for back end FPGA)
Size: 72 Mbits per bank (144 Mbits total)
Bus Width: 18-bits per bank
Speed: Up to 500 MHz clock rate 

Backplane I/O

VME Interface: A32:D32 master interface 
VXS Interface: P0 connector supports 8X high speed serial links
GPIO Interface: P2 connector 
Rear Transition Module (Optional): For rear access to the board, a Rear Transition Module is available that provides connections for GPIO connections, network access, PPS and trigger signals 

Front Panel I/O

Gigabit Ethernet via SFP+
CXP supporting 12 fiber optic at up to 6.4 Gb/s per link 


Standard ANSI / VITA 1.1-1997 (R2003) VMEbus board, 6U x  4HP, single 0.8” slot
Optional VXS P0 connector for backplane I/O 


+5V, +3.3V, ±12V from backplane. Power consumption is dependent on customer application. Power estimation model is provided as part of the Developers Kit.


Contact factory for additional performance details.