The 1000 words of memory consisted of 100 channels of 10-word mercury delay line registers. It used ultrasonic delay line memory. The probe is directed into an optical delay line. There are six channels of 10-word mercury delay line registers as spares. These devices make use of delay line channels tens of centimeters in length. This setting is called differential delay line or vernier delay line. It also sent one of the signals through a short delay line. I think I'd had the new AMS delay line for about two weeks. A later version of the delay line used metal wires as the storage medium. The SAD-512 was a single delay line version. Thus, each symbol in the input codeword will be on distinct delay line. The same delay is caused by the delay line in the encoder. Built in 1949, the EDSAC used a mercury delay line memory. The Williams Tube was much faster than the delay line, but suffered from reliability problems. In operation, bubble memories are similar to delay line memory systems.