Skip Navigation Links | Home | Technology | Multi-Channel Data Acquisition (Daisy Chain)

​Introduction

In today's fast-paced technological landscape, efficient multi-channel data acquisition is crucial for various applications, such as plasma temperature and density measurements in fusion reactors using Thompson scattering, beam position monitoring in particle accelerators, phased-array radar systems, and more. ​PCIe, ​PXIe, and MTCA.4 systems offer a robust solution for high-speed, multi-channel data acquisition, providing unparalleled performance and scalability. These systems enable synchronized data collection on hundreds of channels and additionally support high-speed data transfer rates to processing and/or storage units. Read more about our multi-channel system capabilities and products below.​

Multi-Channel System Clocking and Synchronization​​

In high-speed multi-channel data acquisition systems, precise clocking and synchronization are critical to ensure accurate and reliable data collection. Clocking refers to the timing signals that coordinate the sampling of data across multiple channels, while synchronization ensures that all channels capture data simultaneously, maintaining the integrity and coherence of the acquired signals.

Teledyne SP Devices' data acquisition boards, or digitizers, operate at Gigahertz (GHz) sampling frequencies, necessitating precise and robust clocking and synchronization mechanisms due to tight timing margins. To avoid phase misalignment, an external clock reference—typically 10 MHz—from a common source is distributed to all digitizers in the system, enabling phase-locked synchronized sampling. The digitizer's onboard phase-locked loop (PLL) minimizes clock jitter, achieving extremely low jitter in the range of 200 femtoseconds. This effectively eliminates timing discrepancies and phase shifts, preventing data corruption and analysis errors.

​ Learn more about clocking and synchronization in our multi-channel webinar

​​​

Figure 1. Daisy-chain synchronization in multi-channel system utilizing
Teledyne SP Devices' ADQ8-8C-PXIe digitizer.​​​​​​​​​​​​​​​​​​​​

The Importance of Triggering and Trigger Distribution​

Triggering is a fundamental aspect of multi-channel data acquisition systems, ensuring that data capture begins precisely when required by the application. A trigger signal initiates the data acquisition process, synchronizing the start of data collection across all channels. This is crucial for applications where timing accuracy is paramount, such as event detection, waveform analysis, and real-time monitoring.​

Trigger distribution involves disseminating the trigger signal to all digitizers within the system. At Gigahertz sampling rates, even slight timing discrepancies can lead to data corruption. Achieving picosecond-level accuracy in trigger distribution is essential to ensure synchronized data capture across all channels. One of the key challenges includes trigger jitter, or variations in signal timing, which can severely affect overall performance. Teledyne SP Devices' digitizers include built-in timestamp functionality to effectively resolve potential trigger misalignment caused by jitter.

 ​​​

Figure 2. All Teledyne SP Devices'​ digitizers feature a dedicated hardware trigger.
Here a multi-channel system based on the ADQ36-PXIe product. ​​​​​
Daisy-chain Triggering


Trigger distribution, even minor differences in cable length can cause unwanted timing discrepancies, resulting in trigger misalignment. Additionally, in high-channel count systems with many digitizers, the driving capability—or fan-out—of the common/shared trigger source is often limited. As more digitizers are added to the system, this attenuates the trigger signal level beyond the digitizer's sensitivity, causing the digitizer to miss the trigger event. These challenges limit the achievable channel count, which we address using our daisy-chain solution.

With daisy-chain triggering, only a single primary digitizer receives the external trigger. The system then propagates the trigger signal as a digital signal to the other digitizers. This approach addresses the fan-out issue and ensures very accurate trigger timing precision, better than 50 picoseconds in large systems. Daisy-chain triggering is supported ​by selected digitizer models and can be used with all form factors, including PCIe. An additional advantage for PXIe systems is that the clock reference and synchronization signals can be distributed through the backplane of the chassis, minimizing the use of cables.


 

Figure 3. Daisy-chain block diagram for PCIe (left) utilizing the TRIG, SYNC, and CLK front-panel connectors. PXIe daisy-chain example (right) utilizing the backplane.​​​​​​​​​​​​

The easiest way of evaluating the daisy-chain functionality is to use theDigitizer Studio software. Please watch the video below to learn more.​​​​


For additional technical details, please refer to the webinar below.

Data Transfer, Signal Processing, and Storage

Data acquisition boards efficiently capture and transfer large volumes of data from multiple channels to a host system for processing and/or storage. The boards leverage high-speed interfaces, such as PCIe, to ensure rapid and reliable data transfer. Maximum data transfer capability depends on the type of interface used, and also differs between digitizer models, but ranges up to 14 Gbyte/s streaming capability for a single digitizer.

In multi-channel systems, the aggregate system-level transfer capability is typically higher. However, understanding the underlying architecture and its capabilities and limitations is crucial. One example is the DPS16-PCIe system that supports a system-level transfer rate of 56 Gbyte/s, divided over 16 PCIe slots. Digitizers from Teledyne SP Devices also support so-called peer-to-peer streaming (P2P), allowing direct transfers between the digitizer and other components, such as a graphics processing unit (GPU). More information about P2P is available here.​

 ​​​

Figure 4. DPS16-PCIe offers 16 PCIe slots and supports a system-level
data transfer rate of 56 Gbyte/s.​​​​​​
 
 ​​

All digitizers feature onboard ​AMD field-programmable gate arrays (FPGAs) that can be reconfigured using either a firmware development kit for custom solutions, or optional stand-alone firmware packages that provide application-specific features and functions. FPGA pre-processing is ideal for real-time signal processing, reducing the raw data rate to match the link/interface capacity. Onboard FPGAs also offer a cost-efficient solution for multi-channel systems, potentially eliminating the need for additional processing units.​​​​​

​
However, in certain applications and for certain algorithms, GPUs offer signal processing advantages and software development is generally faster for these devices. That's why peer-to-peer streaming between digitizers and GPUs is a tremendous advantage. Multiple digitizers can even stream to a single GPU, for example, at rates up to 28 Gbyte/s as shown here. Teledyne SP Device's digitizers work with both Nvidia and AMD GPUs, on both Linux and Windows operating systems, and via both PCIe and PXIe interfaces.


 
 

Figure 5. PCIe system (left) with multiple digitizers and GPUs. PXIe system with ADQ7DC-PXIe and ADQ36-PXIe digitizers combined with GPU from RADX in a NI chassis.​​​​​​

Additionally, Solid State Drives (SSDs) play a crucial role in certain multi-channel data acquisition applications, offering high-speed and reliable data recording capabilities. SSDs are favored for their fast read/write speeds, which are essential for handling the large volumes of data generated by these systems. We provide storage solutions for both PCIe and PXIe systems as shown below.

 
 

Figure 6. PCIe system (left) with SSD streaming at 8 Gbyte/s and 8 Terabyte total storage. PXIe system (right) with ADQ36-PXIe, RADX GPUs, and Conduant SSDs in an ADLINK chassis.​

​Contact us for processing and/or storage inquiries​

​​PCI​e Solutions

PCIe multi-channel systems are an emerging trend in the data acquisition field, offering a cost-effective solution without compromising on performance. These systems provide scalability, reliability, and low-latency connectivity, making them an ideal choice for modern high-performance computing environments.

Our multi-channel systems seamlessly integrate with a vast ecosystem of third-party products, including GPUs and SSDs, offering flexible and scalable options for processing and storage. We offer several pre-defined systems with selectable options for motherboard, CPU, GPU, and more. If you are interested in custom systems, please don't hesitate to contact us.

View the video below for a brief overview of a 32-channel PCIe system and click the button below to view available products.


​


​View our multi-channel PCIe products here​

Contact us for custom PCIe configurations​​​

PXIe Solutions

PXIe, or PCI Express eXtensions for Instrumentation, is an advanced standard used in measurement and automation systems. It is similar to PCIe, but additionally offers advanced timing and trigger modules as well as backplane routing for clock and trigger distribution that helps minimize external cabling. Also, PXIe connectors are designed to be rattle-proof and moisture-proof, ensuring durability in various environments. These features make PXIe a powerful choice for high-channel-count and high-data-throughput applications.

Digitizers from Teledyne SP Devices are compatible with PXIe products and infrastructure from major vendors, such as NI, ADLINK, R​ADX, and Conduant. We assist customers in finding the most appropriate solutions for their needs and offer custom engineering services, including integration support and custom development. Our PXIe solutions are utilized by industrial OEM customers and major research facilities worldwide in applications such as particle physics, distributed fiber optic sensing, and more.

​Contact us to discuss PXIe system configurations

 ​​​

Figure 7. 192-channel PXIe system based on ADQ8-8X-PXIe.​​​​​​​​​​​​​​​​​​

MTCA.4 Solutions

MTCA.4, or Micro Telecommunications Computing Architecture 4, is an advanced standard designed for high-performance computing systems. It supports high-speed data transfer and processing and is highly modular, allowing for easy upgrades and maintenance with minimal disruption. Additionally, MTCA.4 systems can be configured for full redundancy, ensuring high reliability and availability in critical systems such as fusion reactors, particle accelerators, etc.​

The MicroTCA Carrier Hub (MCH) is central to MTCA.4 systems, providing platform management and remote access. Remote configuration and monitoring is enabled by the Remote Management Control Protocol (RMCP), and this is a crucial ability in, for example, radioacti​ve environments. Similarly to PXIe, Teledyne SP Devices' digitizers are used by large research facilities internationally, for example, for Thomson scattering measurements at the world's largest fusion stellarator facility Wendelstein 7-X hosted by the Max Planck Institute for Plasma Physics (IPP). Read more about the installation here and contact us below to discuss further.


​Contact us to discuss MTCA system configurations

 ​​​

Figure 8. ADQ7DC-MTCA offers 14 bits resolution and 10 GSPS sampling rate.​​​​​​​