The video isolation choke presents a simple transmission line to the signal, so that its signal amplitude capability is essentially unlimited, and its bandwidth extends from DC to that frequency where line losses become excessive. Isolation increases with increasing noise frequency. The choke provides protection against moderate levels of 60 Hz hum, and protection against very high levels of RF noise. Its hum isolation is greater than the choke. It can sustain very high noise voltages without degradation.
Isolation decreases with increasing noise frequency.
A choke can be added inline to increase protection from high frequency noise. Signal amplitude at low frequencies is limited by core saturation. The choke is primarily used in Broadcast TV because it passes the DC component of the signal. Both transformer and choke can pass camera control signals. Models are available for tight space requirements, and for many different special circumstances.