How to determine if the impedance of FAKRA cable matches

How to determine if the impedance of FAKRA cable matches

To determine whether the impedance of FAKRA cables matches, the following methods can usually be used:

Using professional instruments for measurement

Using a network analyzer: A network analyzer is an instrument specifically designed to measure the characteristics of RF and microwave circuits. It can send signals of different frequencies to FAKRA cables and measure parameters such as reflection coefficient and transmission coefficient. Through these parameters, the characteristic impedance and actual impedance of the cable can be calculated to determine whether the impedance matches.

Using impedance analyzer: Impedance analyzer is mainly used to measure the impedance characteristics of electronic components or circuits. Connect the FAKRA cable to an impedance analyzer, which can directly measure the impedance values of the cable at different frequencies and compare them with the standard FAKRA cable impedance values. If the measured value is within the specified tolerance range, it is considered impedance matching; Otherwise, impedance mismatch.

Observe the quality of signal transmission

Checking signal integrity: When FAKRA cables are used to transmit high-speed signals (such as video and data signals), impedance matching can be determined by observing the integrity of the signal. If the impedance matching is good, the signal should have clear edges, stable amplitude, and correct logic levels during transmission. If the impedance does not match, the signal may exhibit phenomena such as reflection, oscillation, overshoot, and undershoot, resulting in signal distortion and affecting the normal operation of the equipment.

Detecting bit error rate: For data transmission systems, impedance matching can be evaluated by detecting the bit error rate. Under normal working conditions, if the bit error rate is low and within the allowable range of the system, it indicates that the signal transmission quality is good and the cable impedance matching may be good; If the error rate suddenly increases beyond the normal range, in addition to considering other factors, it may also be due to cable impedance mismatch leading to an increase in signal transmission errors.

Check the installation and connection of cables and connectors

Check the physical connection: Carefully inspect whether the connection between the FAKRA cable and the connector is firm and correct. Ensure that the connector is installed in place without any looseness, deformation, or damage. Poor connections may increase contact resistance, thereby disrupting the continuity of impedance and causing impedance mismatch.

Check cable layout: Check whether the cable laying method and layout meet the requirements. Avoid excessive bending, stretching, or compression of cables, as these situations may alter the structure of the cable and affect its characteristic impedance.