The Compensation of Delay Distortion in Video Delay Lines

Delay distortion in ordinary solenoidal delay lines is primarily caused by the decay of solenoid inductance resulting from a reduced magnetic coupling at the higher frequencies. An analysis of the phase characteristic of delay lines which employ solenoid bridging capacitances to compensate for this inductance variation is presented. The relations necessary for determining the delay distortion and effective bandwidth corresponding to any amount of compensation are given. The analysis is verified by observations on several experimental lines, wherein the bridging capacities are obtained by means of isolated metal patches placed in proximity to the solenoid.