Communications Blockset

Sources of Delays

While some blocks are able to determine their current output value using only the current input value, other blocks need input values from multiple time steps to compute the current output value. In the latter situation, the block incurs a delay. An example of this case is when the Derepeat block must average five samples from a scalar signal. The block must delay computing the average until it has received all five samples.

In general, delays in your model might come from various sources:

• Digital demodulators
• Convolutional interleavers or deinterleavers
• Viterbi Decoder block
• Buffering, downsampling, derepeating, and similar signal operations
• Explicit delay blocks, such as Integer Delay and Variable Integer Delay
• Filters

The following discussions include some of these sources of delay.

Computing Delays

ADSL Demo Model