Mismatch
In high-frequency technology, mismatch refers to the case that the internal resistance of a signal source, the wave impedance of the cable and the terminating resistance of the line (e.g. receiver input, antenna, equivalent load ) do not match.
If the wave impedance does not match the terminating resistor, unwanted impulse reflections will occur. The correct value of the terminating resistor is determined by time domain reflectometry and can be corrected using a resonance transformer . At high frequencies ( high frequency ), plug-in connectors must also have a wave impedance that matches the cable to avoid mismatching and joints. In the event of a mismatch, there will be disruptive reflections .
With every interface , whether digital or analog, the output resistance of the source and the input resistance of the load form an adaptation damping . The damping factor for the voltage adjustment at the interface from the power amplifier to the loudspeaker is particularly important here .
The consequences of a mismatch can be:
- Loss of power or even destruction of RF transmitters due to reflected power
- Losses in signal transmission between antenna and receiver
- Distortion of the frequency response of a cable connection
- Runtime and data errors in digital cables due to changed edges and multiple reflections
- poor picture quality for television signals due to frequency response errors and multiple reflections
LF power amplifiers for loudspeakers do not work with power adjustment, but with voltage adjustment . You need to have the lowest possible source impedances of and less in order to dampen the natural oscillations of the 4 to 8 ohm speakers, especially at low frequencies.
See also
- Terminating resistor
- Impedance
- Impedance matching
- Performance adjustment
- Voltage adjustment
- Noise adjustment
- speaker
- Reflection (physics)