As shown in the above, it is air bus ARINC429 specification requirements for transceiver chip input and output impedance

There are some doubt

(1) the figure description of input and output impedance is generally equivalent dc resistance or impedance of the transmission line theory? If is impedance of transmission line, the red block diagram B how demand is 12000 ohm resistor, how to match up and 75 ohms?

(2) for chip (scenario: it's on the PCB board) equivalent dc resistance of input and output, and how to test the equivalent resistance?

CodePudding user response:

1. The intrinsic characteristics of input and output impedance is the device, the ideal device output impedance is 0, the input impedance is + up, what you said and 75 Ω impedance matching, is actually the output impedance of the device and the matching between the transmission line is introduced of your box C, has reached the maximum power transfer (this is the characteristic impedance matching),
2. The measurement you can device output to meet resistance, change two groups corresponding resistance measured voltage value, can launch device impedance,

CodePudding user response:

Output impedance=output open circuit voltage/output short circuit current

CodePudding user response:

One is with frequency characteristics, one is dc characteristics

CodePudding user response:

1. The input impedance only refers to the equipment external impedance at the receiving end, generally larger;
2. The sender general impedance is low, such as less than 80; With close to matching the standard cable;
3. 75 Ω refers to the line impedance, is copper, insulation, shielding, coaxial of the way or double glue, not too much, nor too small, or transmission is bad,