I2L delay circuit with phase comparator and temperature compensator for maintaining a constant delay time

摘要

A delay circuit for delaying an FM video signal is disclosed. The delay circuit includes an input for supplying the FM video signal, an output for producing a delayed FM video signal, and a delay line connected between the input and output for delaying FM video signal. The delay line is defined by a plurality of I2Ls connected in cascade. The delay circuit further includes a phase comparator provided for comparing a phase between FM video signal at the input and the delayed FM video signal at the output and for producing a difference signal representing the phase difference. The difference signal is used for changing and injection current to be applied to the I2Ls such that the delay effected in the delay line is made substantially equal to the required delay.