What is propagation delay?

Propagation delay is the amount of time required for a signal to be received after it has been sent; it is caused by the time it takes for the signal to travel through a medium.

What is propagation delay of flip-flop?

The propagation delay of the flip flops means a small delay occurs between the clock edge and the flip flop output, Q, becoming valid. This is the called the propagation delay of the flip flop and is denoted TFF in the diagram below.

What is propagation delay in combinational logic circuits?

The propagation delay of a combinational circuit is the sum of the propagation delays through each element on the critical path. The contamination delay is the sum of the contamination delays through each element on the short path.

Why does propagation delay happen?

Propagation delay typically refers to the rise time or fall time in logic gates. This is the time it takes for a logic gate to change its output state based on a change in the input state. It occurs due to inherent capacitance in the logic gate.

What affects propagation delay?

Factors that affect propagation delay are: the way it is measured, the amount of overdrive, the supply voltage, the output driver supply voltage, capacitive loading, the common mode voltage, the configuration (inverting or non-inverting), the edge on which one measures (rising or falling) and temperature.

What is the formula for propagation delay?

Propagation delay is equal to d / s where d is the distance and s is the wave propagation speed. In wireless communication, s=c, i.e. the speed of light.

What is propagation and transmission delay?

Propagation delay is how long it takes one bit to travel from one end of the “wire” to the other (it’s proportional to the length of the wire, crudely). Transmission delay is how long it takes to get all the bits into the wire in the first place (it’s packet_length/data_rate).

How can propagation delay be reduced?

Steps to reduce the gate/propagation delay:

  1. Minimize no. of transistors through the propagation path.
  2. Minimize capacitive (C) effect through propagation path, since cap. ‘C’ makes delay=R*C.
  3. By limiting the ‘transitions’ through ‘layers’ as much as possible.
  4. By reducing the capacitive effects at the output.

How can propagation delay be increased?

Increases in output load capacitance, often from placing increased fan-out loads on a wire, will also increase propagation delay.

Is propagation delay constant or variable?

Which of these delays are constant and which are variable? 16. The delay components are processing delays, transmission delays, propagation delays, and queuing delays. All of these delays are fixed, except for the queuing delays, which are variable.