JAJU446A December   2017  – January 2022

 

  1.   概要
  2.   Resources
  3.   特長
  4.   アプリケーション
  5.   5
  6. 1 System Description
    1. 1.1 Key System Specifications
  7. 2 System Overview
    1. 2.1 Block Diagram
    2. 2.2 System-Level Description
    3. 2.3 Highlighted Products
      1. 2.3.1 Analog Signal Chain
        1. 2.3.1.1 LMH5401
        2. 2.3.1.2 LHM6401
        3. 2.3.1.3 BUF802
      2. 2.3.2 Clock
        1. 2.3.2.1 LMK61E2
        2. 2.3.2.2 LMK04828
        3. 2.3.2.3 LMX2594
      3. 2.3.3 Power
        1. 2.3.3.1 TPS82130
        2. 2.3.3.2 TPS7A84
    4. 2.4 System Design Theory
      1. 2.4.1 High-Speed, Low-Phase Noise Clock Generation
      2. 2.4.2 Channel-to-Channel Skew
      3. 2.4.3 Deterministic Latency
        1. 2.4.3.1 Importance of Deterministic Latency
      4. 2.4.4 Analog Front End
      5. 2.4.5 Multichannel System Power Requirement
      6. 2.4.6 Hardware Programming
  8. 3 Circuit Design
    1. 3.1 Analog Input Front End
      1. 3.1.1 High-Input Impedance Buffer Implementation Using the BUF802
    2. 3.2 High-Speed Multichannel Clocking
    3. 3.3 Power Supply Section
      1. 3.3.1 DC-DC
        1. 3.3.1.1 How to Set 2.1-V Output Voltage
      2. 3.3.2 LDOs
  9. 4 Host Interface
  10. 5 Hardware Functional Block
  11. 6 Getting Started Application GUI
  12. 7 Testing and Results
    1. 7.1 Test Setup and Test Plan
    2.     44
    3. 7.2 SNR Measurement Test
    4. 7.3 Channel-to-Channel Skew Measurement Test
    5. 7.4 Performance Test Result
    6. 7.5 Multichannel Skew Measurement
    7. 7.6 49
  13. 8 Design Files
    1. 8.1 Schematics
    2. 8.2 Bill of Materials
    3. 8.3 Altium Project
    4. 8.4 Gerber Files
    5. 8.5 Assembly Drawings
  14. 9 Software Files
  15. 10Related Documentation
    1. 10.1 Trademarks
  16. 11About the Authors
    1. 11.1 Acknowledgment
  17. 12Revision History

2.4 System Design Theory

Channel-to-channel delay is critical in multichannel systems. Applications such as high-speed data acquisition, phase-array radar, and test and measurement require simultaneous measurement of high-frequency signals over many channels. The sampling clocks for the channels must be synchronized to achieve a low skew between the channels.

Achieve synchronous sampling by using proprietary trigger and clock distribution systems within digitizers; do note, however, that this implementation supports a limited number of channels and is not suitable for large-scale multichannel systems.

The distribution of a common high-stability, low-frequency clock reference to all the possible modules and instruments to achieve synchronous sampling across a number of channels presents a major technical challenge at high frequencies. For example, the backplane type of interface busses and connectors may not be suitable for high-frequency signals. A clock pulse deteriorates significantly beyond 100 MHz and introduces jitter. The use of a high-frequency coaxial cable leads to a complex and costly system.