Communications Blockset

Computing Delays

Some models require you to know how long it takes for data in one portion of a model to influence a signal in another portion of a model. For example, when configuring an error rate calculator, you must indicate the delay between the transmitter and the receiver. If you miscalculate the delay, then the error rate calculator processes mismatched pairs of data and consequently returns a meaningless result.

This section illustrates the computation of delays in multirate models and in models where the total delay in a sequence of blocks comprises multiple delays from individual blocks. The section covers the following topics:

• Sources of Delays
• ADSL Demo Model
• Punctured Coding Model

Other References for Delays

Other parts of this documentation set also discuss delays. For information about delays in specific types of blocks, see

• Delays in Digital Modulation
• Delays of Convolutional Interleavers
• Viterbi Decoder block reference page
• Derepeat block reference page

For discussions of delays in simpler examples than the ones in this section, see

• Building a Frequency-Shift Keying Model in Getting Started with the Communications Blockset. (See Delays in the Model.)
• Example: A Rate 2/3 Feedforward Encoder
• Example: Soft-Decision Decoding. (See Delay in Received Data.)
• Example: Delays from Demodulation

Modeling Communication Systems

Sources of Delays