After that the pointer is moved up one value and the system waits for the next sample time. Since a value will wait in its location until the entire memory has been filled, the delay time is determined by the number of memory locations available. As in the analog delay, minor changes in the clock rate will fine tune the delay time. Large changes in the delay time can be made by using separate pointers for the read and write functions. When that is done, the delay time is determined by the difference between the two pointers.
Pitch changing There are some interesting tricks that can be done with a digital delay system.
For instance, suppose we stop the data writing process but continue to read. The output will be the same series of values over and over, and part of the signal will repeat endlessly. The result is the same as a short tape loop with a splice at the point where the writing stopped. Now if you adjust the clock rate, the pitch of the output signal will change, just as it would if you changed the speed of a tape recorder. The pitch will change any time you adjust the clock in a sampled system.