Method and apparatus for dynamically controlling the timing of signals in automatic test systems

Apparatus for delaying an electrical signal comprising:

• a first transmission line having M taps along its length, where M is an integer greater than one;
• a first multiplexer having M input terminals, each connected to a different one of the M taps, the M taps dividing the first transmission line into M-1 segments, wherein the M taps are positioned to delay an electrical signal passing along the first transmission line by a first predetermined delay interval between successive taps, the first multiplexer providing a first delayed signal at a first multiplexer output terminal;
• a second transmission line having N taps along its length, where N is an integer greater than one, the second transmission line being connected to receive the first delayed signal from the first multiplexer output terminal;
• a second multiplexer having N input terminals, each connected to a different one of the N taps, the N taps dividing the second transmission line into N-1 segments, wherein the N taps are positioned to delay an electrical signal passing along the second transmission line by a second predetermined delay interval between successive taps, the second multiplexer providing a second delayed signal at a second multiplexer output terminal;
• and
• wherein the delay of the N-1 segments combined is greater than the delay of a single segment of the first transmission line.

Apparatus for delaying an electrical signal comprising:

• first means for delaying signals by a preselected interval, the first means connected to receive the electrical signal and delay it for up to a predetermined delay interval to provide a first delayed signal;
• N serially connected delay elements, where N is an integer, coupled to receive the first delayed signal and further delay it by transmitting the first delayed signal through a predetermined number of the N delay elements and supply it to an output terminal;
• and
• wherein the first means comprises ramp generating means and the delay elements comprise gate means.

Apparatus connected between an input terminal and an output terminal for delaying an electrical signal supplied to the input terminal before supplying it to the output terminal, the apparatus comprising:

• a first delay line having a plurality of fine taps at intervals thereon, the fine taps dividing the first delay line into a series of fine segments, each segment providing a fine nominally predetermined delay interval, all of the series of fine segments of the first delay line together providing a total fine delay period;
• fine delay means connected to the input terminal to receive the electrical signal, connected to a first node, and connected to each of the fine taps, the fine delay means being operable to pass the electrical signal through a selected series of the fine segments to delay the electrical signal and thereby provide a first delayed signal at the first node;
• a second delay line having a plurality of coarse taps at intervals thereon, the coarse taps dividing the second delay line into a series of coarse segments, each segment providing a coarse nominally predetermined delay interval which is less than the total fine delay period;
• and
• coarse delay means connected to the first node to receive the first delayed signal, connected to the output terminal, and connected to each of the coarse taps, the coarse delay means being operable to pass the first delayed signal through a selected series of the coarse segments to delay the first delayed signal and thereby provide a second delayed signal to the output terminal.