Digital Electronics (ENEL3DE)

Understand basic measurement principles Look at a typical instrumentation system Usually some amplification of the sensor signal is needed

Wakerly doesn’t cover this section For the notes we used Rizzoni, (Principles and Applications of Electrical Engineering, Giorgio Rizzoni, 3rd, revised 4th or 5th edition) and Tocci/Widmer (Digital Systems – Principles & Applications, Ronald J Tocci & Neal S Widmer, 8th edition). Copies of Rizzoni are available in the library. The DAC circuit based on the inverting summer provided a useful hypothetical basis for discussion, but is not a practical circuit. Why? An 8-bit DAC has a...

We talked about the two binary states. We also talked about enabling outputs. Effectively this gives a third state called the off or high impedance state. We refer to this as tri-state logic Digital to analog conversion is the process of taking a value in digital code format (straight binary, BCD, etc.) and converting it into a voltage or current that is proportional to the digital value

We talked about the two binary states. We also talked about enabling outputs. Effectively this gives a third state called the off or high impedance state. We refer to this as tri-state logic Example: A 5-bit DAC has a current output such that a digital input of produces an output of 10 mA. What will Iout be for a digital input of 11101? Solution: Iout = 10 mA for an input of 2010 ⇒ K = 0.5 mA I’out = 0.5mA x 2910 = 14.5 mA

J-K FLIP FLOP

Counters are circuits or networks which count pulses. It is important to define a few terms used in describing various circuits or networks. A sequential circuit is said to be a Moore machine or Moore network if its output is a direct function of its present state only and not of its input.

A register is collection of binary storage cells capable of holding binary information. Since flip-flops are memory elements capable of storing binary information, so a group of flip-flops working together constitute a register. To form an n-bit register, n flip-flops are required. Registers comprise of flip-flops and may contain combinational circuits.

For more complex combinational problems with a larger number of inputs, one can resort to the use of a minimization algorithm, such as Quine-McCluskey. In practice however most designs are implemented using programmable Ics.

A prime implicant of a logic function is a normal product term that cannot be reduced further, obtained from the circled 1s. A minimal sum is a sum of prime implicants.