ANALOG TO DIGITAL CONVERSION AND VICE VERSA WITH DIGITAL CIRCUITORY VIEW.

1. A/D AND D/A CONVERTER
BY
SRIPATI MAHAPATRA

2. AMPLIFIER
An electronic amplifier is a device for increasing the power of a
signal. It does this by taking energy from a power supply and
controlling the output to match the input signal shape but with a
larger amplitude. In this sense, an amplifier may be considered as
modulating the output of the power supply
TYPES OF AMPLIFIER
Inverting Amplifier
Non-Inverting Amplifier

3. OP-AMP (Operational Amplifier)
An Operational Amplifier, or Op Amp, is a dual-input,
single-output amplifier that exhibits a high open-loop gain, high input
resistances, and a low output resistance. One of the inputs of an operational
amplifier amp is non-inverting while the other is inverting.
The output Vout of an operational amplifier without feedback (also known as
open-loop) is given by the formula: Vout = A(Vp-Vn) where A is the open-loop
gain of the op amp, Vp is the voltage at the non-inverting input, and Vn is the
voltage at the inverting input.

4. INVERTING AMPLIFIER
Amplifier whose output polarity is reversed as compared to its input;
such an amplifier obtains its negative feedback by a connection from
output to input, and with high gain is widely used as an operational
amplifier.
GAIN (Av) = -Rf/R1

5. NON-INVERTING AMPLIFIER
An operational amplifier in which the input signal is applied to the
ungrounded positive input terminal to give a gain greater than unity and
make the output voltage change in phase with the input voltage.
GAIN (Av) = 1+RF/R2

6. D/A CONVERTER
Weighted-register D/A converter
R-2R ladder D/A converter
Weighted-register D/A converter
The OP-Amp adder circuit is used to build a Weighted-register D/A
converter by selecting input register that are weighted in binary
progression.

7. Output Voltage (V0) = -RFV1/R1-RFV2/R2-RFV3/R3
V0 = -(RFV1/R1+RFV2/R2+RFV3/R3)
R=2R ladder D/A Converter
An R-2R Ladder is a simple and inexpensive way to perform digital-
to-analog conversion, using repetitive arrangements of precision resistor
networks in a ladder-like configuration.
As its name implies, the R-2R network consists of resistors with only two values,
R and 2R (10K and 20K, respectively, in the circuit shown). The input SN to bit
N is '1' if it is connected to a voltage VR and '0' if it is grounded.

8. Analog to Digital Converter
An analog-to-digital converter (abbreviated ADC, A/D or A to D) is a
device that converts a continuous quantity to a discrete digital number. Or A device
that converts continuously varying analog signals from instruments and sensors
that monitor conditions, such as sound, movement and temperature into binary
code for the computer. The A/D converter may be contained on a single chip or can
be one circuit within a chip.

9. TYPES
Counting A/D Converter
Dual slope A/D converter
Parallel A/D Converter
A/D Converter using voltage for frequency conversion
A/D Converter using voltage to time conversion