Multi-Channel Data Acquisition (Daisy Chain)

One problem facing a digitizing system consisting of more than one digitizer, where synchronicity is desired, is how to distribute the trigger signal. Regardless of method, the end goal is the same: to trigger all the channels at the same time. One naive solution many be to split the trigger signal and pass that to each digitizer through cables of equal length. However, this solution does not scale with the number of digitizers in the system—eventually the trigger signal is attenuated beyond the sensitivity of the analog input. Moreover, by attenuating the signal, the trigger edge is distorted and precision is lost. To address these issues this system features a daisy chain trigger mechanism. The idea is to pass the trigger signal from one device to the next . In order to keep track of the trigger point across all devices, the common time frame, the 10 MHz clock reference is distributed to all boards. Fig. 1 presents a block diagram of a system consisting of two chassis in a daisy chain configuration. The trigger timing precision is measured to 50 ps over large arrays.

Figure 1. Block diagram of the daisy chain trigger mechanism for a system consisting of 16 devices across two chassis.

Solution	ADQ35-INT X 2	DPS7-PCIe	DPS16-PCIe
Description	2 x ADQ35 Interleaved (20 GSPS) + GPU + PC	Industrial PC with 7 PCIe slots + ADQ3x + GPU + PC+ Disks	16 slots per chassi + ADQ3x + GPU + Disks
PC chassis	Rack mounted or tower	Rack mounted	Rack mounted or tower
PCIe expansion chassis	N/A	N/A	Bressner OSS-PCIe3-xxx Bressner OSS-PCIe4-xxx
GPU options	Nvidia Pro A400, A2000 or A4000	Nvidia Pro A400, A2000 or A4000	Nvidia Pro A400, A2000 or A4000
PC motherboard options	ASUS Pro WS WRX80E-SAGE SE WIFI, Supermicro MBD-H12SSL-I-O	ASUS Pro WS WRX80E-SAGE SE WIFI	Supermicro MBD-H12SSL-I-O
PC CPU options	AMD Ryzen Threadripper PRO 5955WX 4 GHz 73 MB, AMD Epyc 7282 - 16 Core, 2.80 GHz, 64 MB	AMD Ryzen Threadripper PRO 5955WX 4 GHz 73 MB	AMD Epyc 7282 - 16 Core, 2.80 GHz, 64 MB
SSD (disk) mounting options	Motherboard or PCIe expansion card	Motherboard or PCIe expansion card	Motherboard or PCIe expansion card
Number of disks	Multiple	Multiple	Multiple
Streaming per disk	6 Gbyte/s	6 Gbyte/s	6 Gbyte/s
Target applications	Wideband RF recording, pulse detection, mass spectrometry, LiDAR, radar, signals intelligence, automated test equipment, digital oscillioscope.	General data acquisition, automated test equipment, LiDAR, particle detection.	Multi-channel single-shot, Thomson scattering, MIMO, synchrotron.
Digitizer Analog Performance
Sampling rate (GSPS)	1 channel at 20 or 2 channels at 10	1 to 10 per channel	1 to 10 per channel
Resolution (bits)	12	12	12
Channel count	1 or 2 (software-selectable)	Up to 14 channels per system	Up to 32 channels per chassis
Bandwidth (GHz)	2.5, 9.0	1.0, 2.5, 9.0	1.0, 2.5, 9.0
Data Streaming and Processing
Throughput (Gbyte/s)	28	14 per slot	3.5 per slot
Duty cycle, continuous streaming	100% with 10-bit compression	100%	Not applicable
GPU	Nvidia Pro A400, A2000 or A4000	Nvidia Pro A400, A2000 or A4000	Nvidia Pro A400, A2000 or A4000
SSD (disk) performance	Up to 28 Gbyte/s streaming	Yes (Linux)	Yes (Linux)
Software and Firmware
Operating system	Linux	Linux, Windows	Linux, Windows
LIBADS	Linux	Linux, Windows	Linux, Windows
Software: design framework for GPU	Digitizer Studio, C, C++, Python, Cuda	Digitizer Studio, LabView, Matlab, C, C++, Python, Cuda	Digitizer Studio, LabView, Matlab, C, C++, Python, Cuda
Firmware	FWATD	All options avaliable	All options avaliable
Hardware Options and Synchronization
19" rack mount option	Yes	Yes	Yes
Master/Slave	N/A	N/A	Stack & Rack -> 32 slots
Timing & synchronization, daisy-chain	+/- 10 ps	+/- 10 ps	+/- 10 ps

Our 7-slot Industrial PC and 16-slot chassi support any ADQ3x product. You can choose any combination of ADQ3x products and set them to any sample rate you need.