US Patent 7620857 Controllable delay device

Two delay chains having in each case n series-connected unidirectional delay elements are provided for controllably delaying electrical signals between a circuit input and at least one circuit output. Each delay element is an active circuit with a fixed transit time. The input of the first delay element of the first chain is connected to the circuit input and the output of each delay element of the first delay chain is selectively connectable to the input of the (n−i+1)th delay element of the second delay chain via a respectively associated switch of a first group of switches, wherein i=1 . . . n is the ordinal number of the delay elements of the first delay chain. The output of the last delay element of the second chain is connected as a circuit output.