The current envelope filter is an electronic component that prevents noisy signals from running inside the sheathed cable sheath, which can cause interference. Using a shear current filter, a ground loop that causes high buzzer and high frequency signals can be prevented.
Depending on the type, the current envelope filter can remove or fix hum on the audio equipment, the scanning frequency in the AV equipment and the unwanted common-mode signal in the coaxial cable.
Video Sheath current filter
Type
There are different types of current sheath filters. Different types have different characteristics and are used to combat various forms of sheathing.
Isolation of transformer
The transformer isolation is a transformer for analog and digital connections of low frequency audio or rarely for high frequencies in antenna cables between TV outlets and devices (tuner, VCR, TV, etc.). This filter then suppresses low-ground loop current currents on the coaxial sheath and coaxial core, which can result from several reasons at different potentials. They affect the signal due to their upper and lower frequency limits and therefore can not transmit DC. In addition, analog signals can experience nonlinear distortions, especially near the device's frequency limit.
Capacitive Capacitor
The spread of ripple current (low frequency) through the antenna cable can be prevented by the capacitive coupling of the two conductors. These elements are available as adapters called braid-breakers or ground breaker and have, both in signal and ground connections, coupling capacitors (with a capacitance of about 1 nF). They are generally only able to pass a frequency greater than about 50 MHz - ripple currents can not flow. Capasitive coupling adapter has an upper limit frequency of about 1 GHz, so UHF signals can pass through. Passband about 50 MHz to 1 GHz makes this device useful for analog and digital television reception, and broadcast FM radio reception. Such ground breakers can not be used in commercial satellite receivers, since low frequency control signals and supply voltages for low noise block converters must be transferred.
Ferrite chokes
The current ferrite sheath filter consists of a ferrite arm around the line or bundle of wires. This is a common choked mode, high-frequency attenuation of common-mode noise on the cable.
They block to high frequencies general mode currents above about 50 MHz and affect the signal and ground connections not in terms of low frequency properties or protective functions. The ferrite sheat filter can not effectively reduce ground loop noise.
Cables for computer peripheral connections often have ferrite beads. The cable can be used to increase the inductance and repeatedly pass through the ferrite core.
The current ferrite sheathing filter can only work effectively if a common-mode signal can flow on the channel. This generally happens when a cable bundle or coaxial cable has ground connections at both ends to the grounded equipment.
To bundle the cable between two devices, but grounded on only one device, in general the ferrite sheath filter is not effective. With such an arrangement, the ferrite bead will only be effective to reduce the surge current wave. When used to remove standing waves, the current ferrite sheath filter should be placed on the current antinode, but not on the standing wave node.
Ferrite beads are available for different frequency ranges and power capacities.
Maps Sheath current filter
Apps
Filter transformer sheath filter is used in low frequency signal channels, where the ground loop otherwise can not be prevented. They are galvanized.
Capasitive coupling filters can be used to prevent loop hum in antennas and radio frequency cables. They also have a galvanic separation.
The current ferrite sheathing filter is used to suppress noise, eradicating sounds like radio frequency interference. They have no electrical insulation and can not prevent ground loops.
See also
- Current sheath
External links
- How to create a custom envelope filter. (Germany)
Source of the article : Wikipedia
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