SLLA573 May   2022 THVD8000

 

  1.   Trademarks
  2. 1Introduction
  3. 2Tests and Setup
    1. 2.1 Test 1: 4-Node Star Network Test
    2. 2.2 Test 2: 4-Node Terminated Star Network Test
    3. 2.3 Test 3: 4-Node Loaded and Terminated Star Network Test
    4. 2.4 Test 4: 4-Node Loaded and Terminated Star Network Test with Line Driver
  4. 3Summary

Test 3: 4-Node Loaded and Terminated Star Network Test

Although adding termination at each node works for the 4-node network, it is logical to wonder if it performs well with a system with many more nodes. To mimic the load of multiple nodes, a 3-Ω resistor represents the lumped load of 40 terminated nodes (Figure 2-7). The lumped load is placed near the transmitter to minimize the impact of long cable.

Figure 2-7 4-Node Loaded and Terminated Star Network

From the GUI and signal integrity check, the communication still works. To conserve space, the GUI looks the same as Figure 2-6 and is omitted for this test. However, it is noticeable that the amplitude of the received signal is significantly reduced (Figure 2-8) due to heavy load and is near the threshold of the THVD8000’s receiver. The small signal has poor signal-to-noise ratio that could create problems in noisy real-world environment.

GUID-20220209-SS0I-RBSR-HZFZ-BLDBPXB8NZTN-low.png Figure 2-8 Waveforms of the 4-Node Loaded and Terminated Star Network