SLAA871 January   2019 AFE7422 , AFE7444

 

  1.   AFE74xx as a single-chip wideband repeater using loopback mode
    1.     Trademarks
    2. 1 Introduction
    3. 2 Repeater Mode (RX-TX Loopback With SerDes Bypassed)
      1. 2.1 Overview of the AFE74xx Repeater Mode
      2. 2.2 Configuration of the AFE74xx as a Repeater
      3. 2.3 Programming the Repeater Mode
        1. 2.3.1 Hardware Setup
        2. 2.3.2 Software Setup and GUI Configuration
    4. 3 130-MHz Digital Repeater System Overview
      1. 3.1 Key System Specifications
    5. 4 System Overview
      1. 4.1 Block Diagram
      2. 4.2 Design Considerations
      3. 4.3 Highlighted Products
        1. 4.3.1 LMK04828
      4. 4.4 System Design Theory
    6. 5 Hardware and Testing
      1. 5.1 Measured Latency and Gain
        1. 5.1.1 Hardware
        2. 5.1.2 Test Setup and Results
      2. 5.2 Measured Linearity Performance
        1. 5.2.1 Hardware and Test Setup
        2. 5.2.2 Test Results
      3. 5.3 Measured Selectivity (Out-of-Band Jammer)
        1. 5.3.1 Hardware and Test Setup
        2. 5.3.2 Test Results
    7. 6 Terminology

2.1 Overview of the AFE74xx Repeater Mode

The AFE74xx support the internal loopback of the 20-bit digital stream from the receiver to the transmitter with the SerDes bypassed. This feature can be used in applications such as repeaters, where the digital output of the RX must be fed back to the input of TX. With this loopback feature, users do not have to physically connect the STX lanes to SRX lanes on their board (through FPGA or ASIC), and gives the following advantages:

  • No requirement to establish a link between the AFE and FPGA because the loopback is established within the device
  • Saves cost and board space because FPGA or ASIC is not required (if no baseband processing is required on the platform)
  • No need for external loopback between SRX and STX lanes; loopback is handled internally