Method and apparatus for remotely buffering test channels

An apparatus comprising:

• a circuit having branches from a common node;
• isolation buffers, each isolation buffer provided in one of the branches;
• and
• buffer bypass elements, each buffer bypass element provided between an input and output of one of the isolation buffers.

A method of measuring the delay of a buffer in a test circuit, the method comprising:

• providing a signal pulse through the buffer;
• measuring the signal pulse as reflected from a buffer bypass element provided between an input and output of the buffer;
• and
• determining the delay introduced by the buffer from the reflected signal pulse using a time domain reflectometer calculation.

A method of measuring the delay of a buffer in a test circuit, wherein the buffer is provided in a first transmission line, the method comprising:

• measuring delay of the first transmission line and the buffer;
• measuring delay of a second transmission line substantially similar to the first transmission line without a buffer;
• and
• calculating the delay through the buffer by determining a difference between a delay through the first transmission line with the buffer and the delay through the second transmission line.