r13 ica lab 2015 manual

IC APPLICATIONS LAB ELECTRONICS & COMMUNICATION ENGINEERING

NARAYANA ENGINEERING COLLEGE ::NELLORE

1

INDEX

S.No Date Name of Experiment Sign Grade



2

CIRCUIT DIAGRAM:

+Vcc

-Vcc

+Vcc

-Vcc

+Vcc

-Vcc

+V

cc

-V

cc

O/P Vo1

-

++3

2

67

4

OP3 TL081C

R2 2k

R3 1k

O/P Vo2

-

++3

2

6

74

OP2 TL081C

R2 2k

R1 1k

O/P V03

+

Input signal (1Volts)

-

++3

2

6

74

OP1 TL081CV2 10V1 10

FIG: Negative Feedback Amplifiers

MODEL WAVEFORMS:

Time (s)

0.00 250.00n 500.00n 750.00n 1.00u

Input signal (Volts)

-1.00

1.00

Output

-1.00

1.00

Fig: Slew rate Measurement at High Frequency for Unity Gain Amplifier



3

EXPERIMENT NO: DATE:

NEGATIVE FEEDBACK AMPLIFIER

AIM:

To Study the Negative feedback Amplifier by Designing the Following amplifiers

a) A unity gain amplifier

b) A non-inverting amplifier with gain of A

c) A inverting amplifier with gain of A

APPARATUS:

S.NO TYPE NAME OF

EQUIPMENT/COMPONENT RANGE QUANTITY

1 Op-Amp IC TL081C - 1

2 Resistors - 1kohms 4

3 Function generator - 0-30MHz 1

4 Regulated power supply - 0-30V(dual) 1

5 IC bread board trainer - 1

6 CATHODE RAY OSCILLOSCOPE - 0-30MHz 1

7 Patch cards and CRO probes - As required

THEORY: An OP-Amp can be used in negative feedback mode to build unity gain amplifiers, non-

inverting amplifiers and inverting amplifiers. While an ideal OP-Amp is assumed to have infinite

open-loop gain and infinite bandwidth, real OP-Amps have finite numbers for these parameters.

Therefore, it is important to understand some limitations of real OP-Amps, such as finite Gain

Bandwidth Product (GB). Similarly, the slew rate and saturation limits of an operational amplifier are

equally important.

An OP-Amp can be considered as a Voltage Controlled Voltage Source (VCVS) with the

voltage gain tending towards infinity. For finite output voltage, the input voltage is practically zero.

This is the basic theory of OP-Amp in the negative feedback configuration.

APPLICATIONS:

Amplifying bioelectric potentials (ECG,EEG,EMG,EGG) and piezoelectric with high output

impedance.

Amplifying sensor output signals (temperature sensors, humidity sensors, pressure

sensors(etc).



4

FREQUENCY RESPONSE:

Frequency (Hz)

10 100 1k 10k 100k 1M 10M

O/P V03

-20.00

10.00

O/P Vo1

-20.00

0.00

O/P Vo2

-20.00

10.00

Fig: Frequency Response of Negative feedback Amplifiers

TABULAR COLOUMS:

Table 1.1:Slew rate:

S.No. Input Frequency Peak to Peak Amplitude of output (Vpp)

1

2

3

4

5

6

Table:1.2:Frequency Response:

S.No. Input Frequency Gain A=Vo/Vi Magnitude variation

1

2

3

4

5

6

7

8

9

10

CALCULATIONS:



5

PROCEDURE:

1. Connect the circuit as per circuit diagram

2. Transient Response:

a. Apply a Square wave of fixed magnitude as an input signal

b. Change the input frequency and study the peak to peak amplitude of the output.

c. Calculate slew rate of amplifiers.

3. Frequency Response:

a. Apply a sine wave of fixed amplitude as a input signal

b. Obtain the gain bandwidth product of individual amplifiers.

4. Calculate the gain in dB for wide range of frequencies for all the three configurations of op-amp

5. Plot the Transient and frequency response of op-amp for all the three configurations

PRECAUTIONS:

1. Avoid Loose connections. 2. Check the Power supply and connections before switch ON

VIVA QUESTIONS:

1. Explain the need for unity gain amplifier?

2. Advantages of Op-Amp based amplifiers as compare to BJT Amplifiers

3. Mention the Applications for Inverting and Non Inverting Amplifiers?

4. Give Your inference on the frequency response of the amplifier?

5. Give the significance of gain-bandwidth product?

RESULT:



6

CIRCUIT DIAGRAM:

Fig: Instrumentation Amplifier

-Vcc +Vcc

+Vcc

-Vcc -Vcc

+Vcc

+Vcc

-Vcc

V1 10

O/P

V2 10

-

+ + 3

2 6

7

4 OP TL081C

-

+ +

3

2 6

7

4 OP1 TL081C

R2 1k

R1 1k

R1 1k

+ I/P V1 Sine/Square Wave 1v

-

+ + 3

2 6

7

4 OP2 TL081C

R3 1k RG 10k

R3 1k

R2 1k

+ I/P V2 Sine/Sqare wave

Vo1

Vo2

Vo3



7


INSTRUMENTATION AMPLIFIER

AIM: To design an Instrumentation amplifier of a differential mode gain of A by using an

Operational Amplifier

APPARATUS: S.NO TYPE NAME OF









THEORY:

Three Op-Amps instrumentation amplifiers are popular because they offer high input

resistance, adjustable differential gain, and high common mode rejection ratio (CMRR).

An instrumentation (or instrumentational) amplifier is a type of differential amplifier that

has been outfitted with input buffer amplifiers, which eliminate the need for input impedance

matching and thus make the amplifier particularly suitable for use in measurement and test

equipment. Additional characteristics include very low DC offset, low drift, low noise, very

high open-loop gain, very high common-mode rejection ratio, and very high input impedances.

Instrumentation amplifiers are used where great accuracy and stability of the circuit both short and

long-term are required.

The most commonly used instrumentation amplifier circuit is shown in the figure. The gain of

the circuit is

Applications:

which used in measuring instruments designed for achieving high accuracy and high stability.

Which used for amplifying low voltage, low frequency and higher output impedance signals.



8

MODEL WAVEFORMS:

Time (s)

0.00 1.00m 2.00m 3.00m 4.00m 5.00m

I/P V1 Sine/Square Wave 1v

-1.00

1.00

I/P V2 Sine/Sqare wave

-500.00m

500.00m

O/P

-2.00

2.00

Fig: Instrumentation Amplifier Response for different i/p Frequencies

TABULAR COLOUMS:

Table 2.1:Slew rate:

S.No. Input Frequency Peak to Peak Amplitude of output (Vpp)

1

2

3

4

5 6

Table:2.2Frequency Response:

S.No. Input Frequency Gain A=Vo/Vi Magnitude variation

1

2

3

4

5

6

7

8

9

10

CALCULATIONS:



9

PROCEDURE:











PRECAUTIONS:

1. Avoid Loose connections. 2. Check the Power supply and Switch ON after connections once verified.

VIVA QUESTIONS:

1. Explain the need for two stages in any instrumentation amplifier.

2. Why CMRR is high for instrumentation Amplifiers?

3. Give some examples for low voltage, low frequency and higher output impedance signals?

4. How does the tolerance of resistors affect the gain of the instrumentation amplifier?

RESULT:



10

CIRCUIT DIAGRAM:

+Vcc

-Vcc

+V

cc

-Vcc

R1 1

k

+ I/P Sine 10Vpp

R2 1k

O/P2:Square w ave-

++3

2

6

74

OP1 TL081C

V2 10V1 10

Fig: Schmitt Trigger

+Vcc

-Vcc

+V

cc

-Vcc

O/P2R 1k

C 1

u

O/P

1

R1 1

k

R2 1k

-

++3

2

6

74

OP1 TL081C

V2 10V1 10

Fig : Astable Multivibrator



11


ASTABLE MULTIVIBRATOR CHARCTERISTICS

AIM: To Study the characteristics of regenerative feedback system with extension to design an

Astable Multivibrator.





3 Capacitor 1uF 1






THEORY:

In electronics a Schmitt trigger is a comparator circuit with hysteresis implemented by

applying positive feedback to the noninverting input of a comparator or differential amplifier. It is an

active circuit which converts an analog input signal to a digital output signal. The circuit is named a

"trigger" because the output retains its value until the input changes sufficiently to trigger a change. In

the non-inverting configuration, when the input is higher than a chosen threshold, the output is high.

When the input is below a different (lower) chosen threshold the output is low, and when the input is

between the two levels the output retains its value. This dual threshold action is called hysteresis and

implies that the Schmitt trigger possesses memory and can act as a bistable circuit (latch or flip-flop).

There is a close relation between the two kinds of circuits: a Schmitt trigger can be converted into a

latch and a latch can be converted into a Schmitt trigger.

Schmitt trigger devices are typically used in signal conditioning applications to remove noise

from signals used in digital circuits, particularly mechanical switch bounce. They are also used

in closed loop negative feedback configurations to implement relaxation oscillators, used in function

generators and switching power supplies.

APPLICATIONS:

It can be used in signal generators and generation of timing signals?

It can be used in code generators and trigger circuit?



12

MODEL WAVEFORMS:

Time (s)

0.00 2.00m 4.00m 6.00m 8.00m

O/P2

-10.00

10.00

VG1

-10.00

10.00

Fig: Schmitt Trigger Output

Time (s)

0.00 10.00m 20.00m 30.00m 40.00m

Out

put

-8.00

-6.00

-4.00

-2.00

0.00

2.00

4.00

6.00

8.00

Fig:Astable Multivibrator Output

CALCULATIONS:



13

PROCEDURE:

1. Connect the Schmitt Trigger circuit as per circuit diagram

2. Apply sine wave as an input for Schmitt Trigger circuit

3. Observe the square wave across the output pin

4. Measure UTP and LTP and compare with theoretical values

5. Modify Schmitt trigger circuit as the Astable Multivibrator circuit

6. Observe the Triangular wave across the output pin

PRECAUTIONS:

1. Avoid Loose connections. 2. Check the Power supply Polarities and Switch ON after connections once verified.

VIVA QUESTIONS:

1. Discuss the difference between astable and b-stable multivibrator?

2. Discuss the frequency limitation of astable multivibrator.

3. Discuss the various applications of Bi-stable?

RESULT:



14

CIRCUIT DIAGRAM:

-Vcc

+V

cc

-Vcc

+Vcc

V1 10

O/P2:VCO

V2 10

-

++

3

2

6

74

OP2 TL081C

R2 10k

R3 1k

+

I/P Square w ave 1v 1kHz

C1 100n

Fig: Integrator Circuit



15


INTEGRATOR CIRCUIT CHARCTERISTICS

AIM: To design and study the characteristics of integrator circuit by using an opampTL081C

APPARATUS:

S.NO TYPE NAME OF




3 Capacitor 1uF 1






THEORY:

The operational amplifier integrator is an electronic integration circuit. Based on

the operational amplifier (op-amp), it performs the mathematical operation of integration with respect

to time; that is, its output voltage is proportional to the input voltage integrated over time.

The frequency responses of the practical and ideal integrator are shown in the above figure.

For both circuits, the crossover frequency , at which the gain is 0 dB, is given by:

The 3 dB cutoff frequency of the practical circuit is given by:

The practical integrator circuit is equivalent to an active first-order low-pass filter. The gain is

relatively constant up to the cutoff frequency and decreases by 20 dB per decade beyond it. The

integration operation occurs for frequencies in the range , provided that . This

condition can be achieved by appropriate choice of and time constants.

APPLICATIONS:

Used in functiongenerators, PI/PID Controllers.

Used in analog computers, analog to digital converters and wave shaping circuits.

Used as a charge amplifier.



16

MODEL WAVEFORMS:

TABULAR COLOUM:

S No I/P Voltage Frequency O/P Voltage

CALCULATIONS:



17

PROCEDURE:











PRECAUTIONS:


VIVA QUESTIONS:

1. Compare the output with that of ideal integrator.

2. How will you design a differentiator and mention its drawback?

3. Discuss the limitation of the output voltage of the integrator?

4. How will you obtain drift compensation in an inverting integrator?

RESULT:



18

CIRCUIT DIAGRAM:

+Vcc

-Vcc

+Vcc

-Vcc

+V

cc

-V

cc

R6

1k

C3 10u

C2

10

0n

R4 1k

R2 10k

R5 10k

R1 10k

-

++

3

2

6

74

OP1 TL081C

C1 100nR3 1k

+ I/P Sine Wave 1v

-

++

3

2

6

74

OP2 TL081C

V2 10

O/P

V1 10

Fig: II Order Butterworth Band Pass Filter



19


II ORDER BUTTER WORTH BAND PASS FILTER

CHARACTERISTICS AIM:

To design a second order Butterworth band-pass filter for the given higher and lower cutoff

frequencies by using an opampTL081C

APPARATUS:

S.NO TYPE NAME OF




3 Capacitor 1uF 3



6 IC bread board trainer - - 1



THEORY:

Bandpass is an adjective that describes a type of filter or filtering process; it is to be

distinguished from passband which refers to the actual portion of affected spectrum. Hence, one

might say "A dual bandpass filter has two passbands." A bandpass signal is a signal containing a band

of frequencies not adjacent to zero frequency, such as a signal that comes out of a bandpass filter.

An ideal bandpass filter would have a completely flat passband (e.g. with no gain/attenuation

throughout) and would completely attenuate all frequencies outside the passband. Additionally, the

transition out of the passband would have brickwall characteristics The bandwidth of the filter is

simply the difference between the upper and lower cutoff frequencies. The shape factor is the ratio of

bandwidths measured using two different attenuation values to determine the cutoff frequency, e.g., a

shape factor of 2:1 at 30/3 dB means the bandwidth measured between frequencies at 30 dB

attenuation is twice that measured between frequencies at 3 dB attenuation.

A band-pass filter can be characterised by its Q factor. The Q-factor is the inverse of the

fractional bandwidth. A high-Q filter will have a narrow passband and a low-Q filter will have a wide

passband. These are respectively referred to as narrow-band and wide-band filters.

APPLICATIONS:

Used in signal conditioning circuits for processing audio signals.

Used in measuring instruments.

Used in Radio receivers.



20

MODEL GRAPH:

Fig: II Order Butterworth Band Pass Filter frequency Response

OBSERVATIONS:

CALCULATIONS

Frequency(Hz) Output voltage(v) Gain(Vo/Vi) Magnitude in db



21

PROCEDURE:





3. Calculate the gain in dB for wide range of frequencies for the configuration of op-amp

4. Plot the frequency response of op-amp for configuration.

PRECAUTIONS:


VIVA QUESTIONS:

1. Discuss the effect of order of the filter on frequency response?

2. How will you vary Q factor of the frequency response.

3. Discuss the need for going to sallen key circuit.

4. Compare the performance of Butterworth filter with that of Chebyshev filter.

RESULT:



22

CIRCUIT DIAGRAM:

+Vcc

+V

cc

-Vcc-V

cc

C3

1u

C2 470n

R3

3.3

k

R2 6.6k R1 6.6k

C1 470n

V2 10Output : C.R.O

+

Input signal (1 Volts)

V1 10

-

++3

2

6

74

OP1 TL081C

FIG: Notch Filter



23


NOTCH FILTER CHARACTERISTICS

AIM:

To design a notch filter to eliminate the 50Hz power line frequency by using an op-amp

TL081C

APPARATUS:

S.NO TYPE NAME OF




3 Capacitor - 1uF 3






THEORY:

Operational amplifiers can be used to make notch filter circuits. Here shown a twin T notch

filter circuit.A notch filter is used to remove a particular frequency, having a notch where signals are

rejected. Often they are fixed frequency, but some are able to tune the notch frequency. Having a

fixed frequency, this operational amplifier, op amp, notch filter circuit may find applications such as

removing fixed frequency interference like mains hum, from audio circuits.

The twin T notch filter with variable Q is a simple circuit that can provide a good level of

rejection at the "notch" frequency. The variable Q function for the twin T notch filter is provided by

the potentiometer placed on the non-inverting input of the lower operational amplifier

The notch filter circuit can be very useful, and the adjustment facility for the Q can also be

very handy. The main drawback of the notch filter circuit is that as the level of Q is increased, the

depth of the null reduces. Despite this the notch filter circuit can be successfully incorporated into

many circuit applications

Applications:

Used for removing power supply interference.

Used for removing spur in RF Signals.



24

MODEL GRAPH:

Frequency (Hz)

10 100

Output

-50.00

0.00

Fig: Notch Filter Frequency Response

OBSERVATIONS:

CALCULATIONS

Frequency(Hz) Output voltage(v) Gain(Vo/Vi) Magnitude in db



25

PROCEDURE:





3. Calculate the gain in dB for wide range of frequencies for the configuration of op-amp

4. Plot the frequency response of op-amp for configuration.

PRECAUTIONS:


VIVA QUESTIONS:

1. Explain the effect of supply frequency interference while amplifying sensor signals?

2. Suggest a method for adjusting the Q factor of the frequency response of NOTCH filter?

3. What is the Purpose of going for Twin T notch filter circuit?

RESULT:



26

CIRCUIT DIAGRAM:

FIG:Self tuned filter based on a voltage controlled filter



27


SELF TUNED FILTER CHARACTISTICS

AIM: Design and test a high-Q Band pass self tuned filter for a given center frequency.

APPARATUS:

S.NO TYPE NAME OF



2 Universal Active Filter IC UAF42 - 1


4 Capacitor - 1uF 1





9 Patch cards and CRO probes - - As required

THEORY:

The self tuned filter is shown in figure. The universal active filter is follwed byanother

integrator with multiplier,Then the circuit becomes a voltage controlled filter or a voltage controlled

phase generator.This forms the basic circuit for self tuned filter.

The output of the self tuned filter for square wave inpit, including the control voltage

waveform. For varying input frequency the output phase will alays lock to the input phase with 90.

APPLICATIONS:

Used in Spectrum Analyzers.



28

FREQUENCY RESPONSE

Fig:Self tuned filter output

CALCULATIONS:



29

PROCEDURE:



a. Apply a square wave of fixed amplitude as a input signal

b. Obtain the output for 1kHz input frequency.

3. Measure the output amplitude at varying input frequency at fixed input amplitude.

4. Output amplitude should remain constant for varying input frequency within the lock

range of the system.

5. Plot the input and output waveforms on graph sheet.

PRECAUTIONS:


VIVA QUESTIONS:

1. Discuss the effect of the harmonics when a square wave is applied to the filter.

2. Determine the lock range of the self tuned filter.

RESULT:



30

CIRCUIT DIAGRAM:

+Vcc

-Vcc

+Vcc

+V

cc

-Vcc-V

cc

O/P 1:Sqrw av

C1 470n

R4 3

.3k

R2 3

.3k

R1 6.6k

-

++3

2

6

74

OP2 TL081C

V2 10O/P2:Tri Wav

V1 10

-

++3

2

6

74

OP1 TL081C

Fig:Function generator circuit



31


FUNCTION GENERATOR

AIM: To design and test a function generator that can generate square wave and triangular wave

output for a given frequency by using an opampTL081C

APPARATUS:

S.NO TYPE NAME OF




3 Capacitor 1uF 1






THEORY:

The feedback loop is made up of a two bit A/D converter(+ or V levels), also called

Schmitt trigger and an integrator. The circuit is also known as a function generator is shown in figure

1. And the output of the function generator is shown in figure 2.

Applications:

Used in testing, measuring instruments and radio receivers.

Used For obtain frequency response of devices and circuits.

Used for testing and servicing of electronic equipments.

Used in electronic musical instruments

Used for obtaining audiograms(threshold of audibility Vs frequency)



32

MODEL WAVEFORMS:

Time (s)

0.00 20.00m 40.00m 60.00m 80.00m

O/P 1

-10.00

10.00

O/P2

-10.00

10.00

Fig: Function Generator Output waveforms

CALCULATIONS:



33

PROCEDURE:


2. Observe the output across the opamp1 which is an square wave

3. The output of an op-amp 1 (ie square wave) is applied as an input for opamp2

4. Observe the output across the opamp2 which is an triangular wave

PRECAUTIONS:

1. Avoid Loose connections.

2. Check the Power supply and Switch ON after connections once verified.

VIVA QUESTIONS:

1. Discuss typical specifications of a general purpose function generator?

2. How can you obtain reasonably accurate sine wave from triangular wave?

3. Discuss the reason for higher distortion in sine wave produed by function generators?

4. What do you mean by Duty cycle and how can you vary the same in a function generator?

RESULT:



34

CIRCUIT DIAGRAM:

+Vcc

-Vcc

+Vcc

+V

cc -Vcc

-Vcc

+ VG1 500m

D2 1N4007

R5 220k

R3 10kD1 1N4007

O/P 1:Sqrw av

C1 2

2n

R4 2

2k

R2 2

2k

R1 22k

-

++

3

2

6

74

OP2 TL081C

V2 10O/P2:Tri Wav

V1 10

-

++3

2

6

74

OP1 TL081C

FIG: Voltage Controlled Oscillator



35


VOLTAGE CONTROLLED OSCILLATOR

AIM: Design and test voltage controlled oscillator for a given specification (voltage range and

frequency range)

APPARATUS:

S.NO TYPE NAME OF

EQUIPMENT / COMPONENT RANGE QUANTITY


2 Diodes - IN4007 2


4 Capacitor - 1uF 1






THEORY:

A voltage-controlled oscillator or VCO is an electronic oscillator whose oscillation

frequency is controlled by a voltage input. The applied input voltage determines the instantaneous

oscillation frequency. Consequently, modulating signals applied to control input may cause frequency

modulation (FM) or phase modulation (PM). A VCO may also be part of a phase-locked loop. VCOs

can be generally categorized into two groups based on the type of waveform produced: 1) harmonic

oscillators, and 2) relaxation oscillators.

Linear or harmonic oscillators generate a sinusoidal waveform. Harmonic oscillators in electronics

usually consist of a resonator with an amplifier that replaces the resonator losses (to prevent the

amplitude from decaying) and isolates the resonator from the output (so the load does not affect the

resonator). Some examples of harmonic oscillators are LC-tank oscillators and crystal oscillators. In a

voltage-controlled oscillator, a voltage input controls the resonant frequency.

Relaxation oscillators can generate a sawtooth or triangular waveform. They are commonly used in

monolithic integrated circuits (ICs). They can provide a wide range of operational frequencies with a

minimal number of external components. Relaxation oscillator VCOs can have three topologies: 1)

grounded-capacitor VCOs, 2) emitter-coupled VCOs, and 3) delay-based ring VCOs.The first two of

these types operate similarly. The time spent in each state depends on the rate of charge or discharge

of a capacitor. The delay-based ring VCO operates somewhat differently however. For this type, the

gain stages are connected in a ring. The output frequency is then a function of the delay in each stage.

APPLICATIONS:

Used in Phase Lock Loop Circuits. Used in Frequency modulation circuits. Used in Function generators. Used in Frequency Synthesizers of Communication equipments



36

MODEL WAVEFORMS:

Time (s)

0.00 100.00m 200.00m 300.00m 400.00m 500.00m

O/P 1

-10.00

10.00

O/P2

-10.00

10.00

VG1

-1.00

2.00

Fig: Output of the VCO

Table: Change in frequency as a function of control voltage

S.No Control Voltage (Vc) Change in Frequency

CALCULATIONS:



37

PROCEDURE:

1. Build the circuit as shown circuit diagram on ALSK Kit.

2. Observe the VCO output waveform

3. Plot the observed input ,Output waveforms.

PRECAUTIONS:


VIVA QUESTIONS:

1. Discuss the following characteristics of a voltage controlled oscillator? i)Tuning range ii)Tuning Gain iii)Phase noise

2. Compare the performances VCO based Harmonic Oscillators and Relaxation Oscillators

3. What are ther various methods adopted in controlling the frequency of Oscillation in VCOs

4. Discuss any one method of obtaining FM Demodulation using aVCO.

RESULT:



38

CIRCUIT DIAGRAM:

Fig: PLL Circuit



39


PHASE LOCKED LOOP

AIM: Design and test a PLL to get locked to a given frequency f. Measure the locking range of the

system and also measure the change in phase of the output signal as input frequency is varied within

the lock range.

APPARATUS:

S.NO TYPE NAME EQUIPMENT

/ COMPONENT RANGE QUANTITY

1 Op-Amp IC TL081C, - 2

2 Analog Multiplier IC MPY634 - 2


4 Capacitor 1uF 2



7 ASLK trainer KIT - - 1



THEORY: A PLL is a feedback system that includes a VCO, phase detector, and low pass filter within its

loop. Its purpose is to force the VCO to replicate and track the frequency and phase at the input when

in lock. The PLL is a control system allowing one oscillator to track with another. It is possible to

have a phase offset between input and output, but when locked, the frequencies must exactly track.

The PLL output can be taken from either Vcont, the filtered (almost DC) VCO control voltage, or

from the output of the VCO depending on the application. The former provides a baseband output that

tracks the phase variation at the input. The VCO output can be used as a local oscillator or to generate

a clock signal for a digital system. Either phase or frequency can be used as the input or output

variables.

Of course, phase and frequency are interrelated by:

Applications:

There are many applications for the PLL,

VCO. In PLL applications, the VCO is treated as a linear, time-invariant system. Excess phase of the

VCO is the system output.

LOCK Range:Range of input signal frequencies over which the loop remains locked once it has

captured the input signal. This can be limited either by the phase detector or the VCO frequency

range.

Capture range: Range of input frequencies around the VCO center frequency onto which the loop

will lock when starting from an unlocked condition. Sometimes a frequency detector is added to the

phase detector to assist in initial acquisition of lock.



40

MODEL WAVEFORM:

Fig: Output of PLL

CALCULATIONS:



41

APPLICATIONS:

Used in tracking band pass filter for angle modulated signals Used in Frequency divider and frequency multiplier circuits. Used as Amplifiers for angle modulated signals Used in AM and FM Demodulators Used in Suppressed carrier recovery circuits

PROCEDURE :

1. Build the circuit on ASLK KIT as shown in circuit diagram.

2. Measure the lock range of the system and measure the change in the phase of the ouput

signal as input frequency is varied within the lock range.

3. Vary the input frequency and obtain the change in the control voltage.

4. Plot output wave forms on graph sheet.

PRECAUTIONS:

1. Avoid Loose connections. 2. Handle the ASLK KIT with carefully 3. Check the Power supply polarities and Switch ON after connections once verified.

VIVA QUESTIONS:

1. Draw the block diagram of a PLL based divider and multiplier and explain the functions performed by each block.

2. Distinguish between lock range and capture range, explain the method of estimating the same for a given PLL Circuit?

3. Discuss the differences between analog phase lock loop and digital phase lock loop.-

RESULT:



42

CIRCUIT DIAGRAM:

Fig: Automatic Gain control



43


AUTOMATIC GAIN CONTROL

AIM: Design and test an AGC system for a given peak amplitude of sine wave output.

APPARATUS:

S.NO TYPE NAME EQUIPMENT

/ COMPONENT RANGE QUANTITY

1 Op-Amp IC TL081C, - 1

2 Analog Multiplier IC MPY634 - 2


4 Capacitor 1uF 2






THEORY

Automatic Gain Control or AGC is a circuit design which maintain the same level of

amplification for sound or radio frequency. If the signal is too low the AGC circuit will increase

(amplify) the level and if is to high will lower it to maintain a constant level as possible. The

Automatic Gain Control principle is widely use in AM receivers and sometimes AGC is called an

compressor-expander because it acts just like one.

Simple AGC: It is implemented in the form of a circuit which extracts the dc offset voltage which is

present along with the demodulated message. This voltage is fed as degenerative or negative feedback

to the control the gain of super heterodyne receivers.

Delayed AGC: In simple AGC circuits even if the signal level received is low, the AGC circuit

operates and the overall gain of the receiver gets reduced. To avoid this situation, a delayed AGC

circuit is used. In this case AGC bias voltage is not applied to amplifiers, until signal strength has

reached a predetermined level after which AGC bias is applied like simple AGC.

APPLICATIONS:

Used in AM Receivers

Used as Voice Operated Gain Adjusting Device (VOGAD) in Radio Transmitters

Used in Telephone speech Receivers, Used in Radar Systems.



44

MODEL WAVEFORMS

Fig:Input-Output Characteristics of AGC/AVC

Table :Transfer Characteristics of AGC/AVC

S.No Input Voltage Output Voltage

CALCULATIONS:



45

PROCEDURE :


2. Apply the sine wave asinput signal from function generator.

3. Vary the input frequencys amplitude and obtain the change in the voltage.

4. Plot output wave forms on graph sheet.

PRECAUTIONS:

1. Avoid Loose connections. 2. The ASLK KIT ,handle with care. 3. Check the Power supply and Switch ON after connections once verified.

VIVA QUESTIONS:

1. Explain clearly the need for AGC in AM Receivers.

2. Draw the block diagram of feedback and feed forward AGC systems and explain the functions of each block

3. Discuss any one gain control mechanism present in biological systems.

4. How can you use AGC in a received signal strength indicator(RSSI)?

RESULT:



46

CIRCUIT DIAGRAM:

Vcc -Vcc

Vcc

-Vcc

-

++

U1 TLC081

V+ 15V1 15

Z1 1N5920

R1 10k

R2 10k

T1 BC108

Vout

R3 10k

R4

100-1000Ohms

6.2V Zener

Fig: LDO circuit



47


LOW DROP OUT REGULATOR

AIM: Design and test a low Dropout regulator using op-amps for a given voltage regulation

characteristic and compare the characteristics with TPS7250 IC.





3 Potentiometer - 100 to 1000Ohms 1

4 Capacitor - - -






THORY:

TPS40200 evaluation module included on Kit. Kit uses the TPS40200 non

synchronous buck converter to provide a resistor selected, 3.3v or 5v output that delivers up to 2.5A

from up to 16V input bus. The evaluation module operates from a single supply and uses the single P-

channel power FET and schottky diode to produce a low cost buck converter.

APPLICATIONS

Used in Power supply of all Electronic Instruments and Equipments

Used as Reference Power Supply in Comparators

Used in Emergency Power Supplies

Used in Current Sources



48

MODEL GRAPH:

Fig:Load regulation characteristics in LDO

Fig: Line Regulation characteristics in LDO

TABULAR COLOUS:

S.No Reference Voltage Output Voltage

1

2

3

Table: Variation of Load Regulation with Load Current in an LDO

S.No Reference Voltage Output Voltage

1

2

3

Table: Line Regulation in LDO

CALCULATIONS:



49

PROCEDURE :


2. Line Regulation:

a.Vary the input voltage from 5.5v to 11v in steps of 0.5v

b.Plot the output voltage as the function of the input voltage for a fixed output load

3. Load Regulation:

a. Vary the load such that load current varies and obtain the output voltage for a fixed

input voltage

4. Plot Line regulation and Load Regulation on graph sheet.

PRECAUTIONS:

1. Avoid Loose connections. 2. The ASLK KIT ,handle with care 3. Check the Power supply and Switch ON after connections once verified.

VIVA QUESTIONS:

1. Distinguish between Load Regulation and Line Regulation.

2. Mention Some of the other important parameters in selecting a LDO.

3. What is power supply rejection ratio(PSRR)

RESULT:



50

CIRCUIT DIAGRAM

+Vcc+

Vc

c

-Vcc

-V

cc

VF1

+I/P Triangular 5Vpp

Vref 1V 1

R1

10

0k

L1 1m

C1

1u

V2 10V1 10

-

++

3

2

6

74 OP1 TL081C

Fig:DC-DC Converter



51


DC-DC CONVERTOR

AIM: Design of a switched mode power supply that can provide a regulated output voltage for a

given input range using the TPS40200 IC

APPARATUS:

S.NO TYPE NAME OF


1 Op-Amp IC TL081C/TMS40200 - 1


3 Capacitor - 1uF 1

4 Inductor - 1mH 1



7 ASLK trainer KIT - 1



THEORY:

Function generator is the basic block for DC-DC converter. The triangular output of the

function generator with peak amplitude Vp and frequency F is fed to the comparator whose other

input is connected to the reference voltage Vref. The output of this comparator is the PWM (Pulse

width modulation) waveform whose duty cycle is given by

where T is time period of triangular wave and is equal to .1/F

This duty cycle is directly proportional to reference voltage Vref. If we connect the lossless

low-pass filter (LC filter) at the output of the comparator as shown in Figure , it is possible to get

stable DC voltage with high efficiency

APPLICATIONS:

Used is DSL/Cable Modems

Used in Distributed Power Systems.



52

MODEL WAVEFORM:

TABULAR COLOUMS:

CALCULATIONS:



53

PROCEDURE:

1. Build the Circuit as per shown circuit diagram.

2. Apply the triangular wave as an input to op-amp.

3. Observe the Transient response of the system

4. Plot the observed the response

PRECAUTIONS:

1. Avoid loose connections

2. Carefully Handle the ASLK Kit

3. Check the power supply Polarities and switch ON after Connections verified.

VIVA QUESTIONS:

1. Discuss the effect of varying the input voltage for a fixed regulated output voltage over the

duty cycle of PWM?

2. Draw the PWM Wave form?

RESULT:

r13 ica lab 2015 manual

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