When testing a signal with an output impedance of 50Ω using a Pico oscilloscope, a 50Ω to 1MΩ direct terminal is required. Recently, during an on-site test with a client, I found that the waveform oscillated severely, as shown in Figure 1 (red box), making it impossible to conduct accurate data analysis. Figure 1 Severe … Read more
Click the blue text above to follow us The main reason for adding a 22Ω or 33Ω resistor in series when a microcontroller uses SPI to connect to a sensor or controller is to suppress reflections and ringing. 1 Principle of Reflection and Source Matching In high-speed digital signal transmission, when the signal driver (such … Read more
For more experience sharing, follow RF Engineer When a microcontroller or FPGA sends SPI control signals to a phase-locked loop chip, it often requires a series connection of a 22 ohm or 33 ohm resistor. What is the reason for this? Impedance discontinuities can cause electromagnetic wave reflections, which in turn lead to signal distortion. … Read more