SLAA870 February   2019 AFE7422 , AFE7444

 

  1.   Evaluating the frequency hopping capability of the AFE74xx
    1.     Trademarks
    2. 1 Introduction
    3. 2 Phase Coherency vs Phase Continuity
    4. 3 AFE74xx Architecture
      1. 3.1 AFE74xx Receivers: Multiband DDC
      2. 3.2 AFE74xx Transmitters: Multiband DUC
      3. 3.3 Numerically Controlled Oscillator (NCO)
        1. 3.3.1 Programming the NCO frequency
          1. 3.3.1.1 Example: Programming NCO to 1700MHz
        2. 3.3.2 Direct Digital Synthesis (DDS) Mode
    5. 4 Frequency Hopping Methods
      1. 4.1 Maintaining Phase Continuity
        1. 4.1.1 Phase Continuous Hop Time
          1. 4.1.1.1 Serial Peripheral Interface (SPI)
          2. 4.1.1.2 Test Setup
          3. 4.1.1.3 Software Configuration
          4. 4.1.1.4 Test Results
      2. 4.2 Maintaining Phase Coherency
        1. 4.2.1 TX NCO Hopping Using SPI
          1. 4.2.1.1 TX NCO Switch Using SPI Hop Time
            1. 4.2.1.1.1 Software Configuration
            2. 4.2.1.1.2 Test Results
          2. 4.2.1.2 AFE74xx DAC Settling Time
            1. 4.2.1.2.1 Hardware Setup
            2. 4.2.1.2.2 Software Configuration
            3. 4.2.1.2.3 Test Results
        2. 4.2.2 RX NCO Hopping Using the GPIO Pins
          1. 4.2.2.1 Test Setup
          2. 4.2.2.2 Software Configuration
          3. 4.2.2.3 Test Results
    6. 5 NCO Frequency Resolution Versus Hop Time
    7. 6 Fast Frequency Hopping With the Load and Switch
    8. 7 Register Addresses
    9. 8 References

AFE74xx Transmitters: Multiband DUC

As for the transmitter, each DAC in the AFE74xx contains a dual-band digital upconverter (DUC), also known as a multi-DUC, and each DUC contains two, independently programmed, back stage NCO accumulators. Figure 4 shows the basic block diagram of one TX_TOP (including two transmitters) in the AFE74xx, where the signal processing features of each of the two multi-DUCs is highlighted in the shadowed area.

afe7422-transmitter-block-diagram.gifFigure 4. Basic Block Diagram of AFE74xx Multi-DUC Architecture