.....

a total solution for

Educational Lab Trainers

ASK MOD. / DEMOD. KIT

BCT-12

B-4,Lotus C.H.S., Near P&MC. Bank, Plot No. 8,

Sector-7, Airoli, Navi Mumbai - 400 708.
Tel.: 022-65116548 / Telefax : 27694323
Email: sales@kitektechnologies.com
W e b s i t e : w w w. k i t e k t e c h n o l o g i e s . c o m
 ASK Modulation & Demodulation Kit

SPECIFICATION
1
ASK MODULATION & DEMODULATION KIT (MODEL:BCT-12)
D Clock Generator
- Selectable Data Generator using 74165.
- Programmable Cyclic 8-bit Word Generator
- Eight way DIP switch provided to create 8-bit word
D Carrier Generator
- Provides Sine waveform output using IC 8038.
- Frequency variable maximum up to 30 KHz.
- Amplitude variable up to Maximum 5V p-p
D Code Display
- Eight LED display to verify the input data
D On-board Block features
- ASK -modulator circuit using IC 4066
- ASK -Demodulator using IC TL084
- Block Description Screen printed on glassy epoxy PCB
D Interconnections
- All interconnections are made using 2mm banana Patch cords.
D Test points are provided to analyze signals at various points.
D All ICs are mounted on IC Sockets.
D Bare board Tested Glass Epoxy SMOBC PCB is used.
D In-Built Power Supply of ±12V/250mA with Power ON indication
D Attractive Wooden enclosures of Light weight Australian Pine Wood.
D Set of 2mm Patch cords for interconnections
D User’s Manual with sample experimental programs

1
ASK Modulation & Demodulation Kit

INTRODUCTION
2
In radio transmission, it is necessary to send audio signal (e.g. Music, speech etc.) from a
broad casting station over great distances to a receiver. This communication of audio
signal does not employ any wire and is sometimes called wireless. The audio signal
cannot be sent directly over the air for appreciable distance. Even if the audio signal is
converted into electrical signal, the later cannot be sent very far without employing large
amount of power. The energy of a wave is directly proportional to its frequency. At audio
frequencies (20Hz to 20 KHz) the signal power is quite small and radiation is not
practicable.
The radiation of electrical energy is practicable only at high frequencies e.g. above 20
KHz. The high frequency signals can be sent thousand of miles even with comparatively
small power. Therefore, if audio signal is to be transmitted properly, some means must be
devised which, will permit transmission to occur at high frequencies while it simultaneously
allows the carrying of audio signal. This is achieved by imposing electrical audio signal on
high frequency carrier. The resultant waves are known as modulated waves or radio waves
and the process is called modulation. At the radio receiver, the audio signal is extracted
from the modulated wave by the process called demodulation. The signal is then amplified
and reproduced into sound by the loudspeaker.

MODULATION
Modulation is a process of mixing a signal with a sinusoid to produce a new signal. This
new signal, conceivably, will have certain benefits of an un-modulated signal, especially
during transmission. If we look at a general function for a sinusoid:
ωt + ϕ )
f(t) = Asin(ω ————— eqn.A
we can see that this sinusoid has 3 parameters that can be altered, to affect the shape of
the graph. The first term, A, is called the magnitude, or amplitude of the sinusoid. The next
term, ω is known as the frequency, and the last term, ϕ is known as the phase angle. All 3
parameters can be altered to transmit data.
The sinusoidal signal that is used in the modulation is known as the carrier signal, or
simply “the carrier”. The signal that is being modulated is known as the “data signal”. It is
important to notice that a simple sinusoidal carrier contains no information of its own.
A high frequency carrier wave is used to carry the audio signal which is done by changing
some characteristic of carrier wave in accordance with the signal. Under such conditions,
the audio signal will be contained in the resultant wave. In modulation, some characteristic
of a carrier wave is changed in accordance with the intensity (i.e. Amplitude) of the signal.
The resultant wave is called modulated wave or radio wave and contains the audio signal.
Therefore, modulation permits the transmission to occur at high frequency while it simulta-
neously allows the carrying of the audio signals.

Types of Modulation
There are 3 different types of modulation: Amplitude modulation, Frequency modulation,
and Phase modulation. From the eqn.A we can see that there are three variable factors in
it and so modulation can be done to all this three parameters.

2
 ASK Modulation & Demodulation Kit

NEED FOR MODULATION

Modulation is extremely necessary in communication system due to the following reasons.

1. PRACTICAL ANTENNA LENGTH

In order to transmit a wave effectively, the length of the transmitting antenna should be
approximately equal to the wavelength of the wave.
8
Velocity 3 x 10
Now Wavelength = ——————— = ——————— meters
frequency frequency (Hz)

As the audio frequencies range from 20Hz to 20 KHz, therefore, if they are transmitted
directly into space, the length of the transmitting antenna required would be extremely
large. For instance, to radiate a frequency of 20 KHz directly into space, we would need an
8 3
antenna length of 3 x 10 \ 20 x 10 = 15,000 meters. This is too long antenna to be
constructed practically. For this reason, it is impracticable to radiate audio signal directly
into space. On the other hand, if a carrier wave say of 1000 KHz is used to carry the
signal, we need an antenna length of 300 meters only and this size can be easily
constructed.

2. OPERATING RANGE
The energy of a wave depends upon its frequency. The greater the frequency of the wave,
the greater is the energy possessed by it. As the audio signal frequencies are small,
therefore these cannot be transmitted over large distance if radiated directly into space.
The only practical solution is to modulate a high frequency carrier wave with audio signal
and permit the transmission to occur at this high frequency (i.e. carrier frequency).

3. WIRELESS COMMUNICATION
One desirable feature of radio transmission is that it should be carried without wires i.e.
radiated into space. At audio frequencies radiation is not practicable because the
efficiency of radiation is poor. However, efficient radiation of electrical energy is possible
at high frequencies (>20 KHz). For this reason, modulation is always done in
communication systems.

3
ASK Modulation & Demodulation Kit

CONCEPT OF AMPLITUDE SHIFT KEYING

3
Digital Communications became important with the expansion of the use of computers and
data processing and have continued to develop into a major industry providing the
interconnection of computer peripherals and transmission of data between distant sites.
Any digital modulation scheme uses a finite number of distinct signals to represent digital
data.

Introduction
There are three major classes of digital modulation techniques used for transmission of
digitally represented data:
™ Amplitude-shift keying (ASK)
™ Frequency-shift keying (FSK)
™ Phase-shift keying (PSK)
Amplitude-shift keying (ASK) is a form of modulation that represents digital data as
variations in the amplitude of a carrier wave.
The amplitude of an analog carrier signal varies in accordance with the bit stream
(modulating signal), keeping frequency and phase constant. The level of amplitude can be
used to represent binary logic 0s and 1s. We can think of a carrier signal as an ON or OFF
switch. In the modulated signal, logic 0 is represented by the absence of a carrier, thus
giving OFF/ON keying operation and hence the name given.
Like AM, ASK is also linear and sensitive to atmospheric noise, distortions, propagation
conditions on different routes in PSTN, etc. Both ASK modulation and demodulation pro-
cesses are relatively inexpensive. The ASK technique is also commonly used to transmit
digital data over optical fiber. For LED transmitters, binary 1 is represented by a short
pulse of light and binary 0 by the absence of light. Laser transmitters normally have a fixed
“bias” current that causes the device to emit a low light level. This low level represents
binary 0, while a higher-amplitude light wave represents binary 1.
In this method the amplitude of the carrier assumes one of the two amplitudes dependent
on the logic states of the input bit stream. A typical output waveform of an ASK modulator
is shown in the figure below. The frequency components are the USB and LSB with a
residual carrier frequency. The low amplitude carrier is allowed to be transmitted to ensure
that at the receiver the logic 1 and logic 0 conditions can be recognized uniquely.

4
 ASK Modulation & Demodulation Kit

Amplitude Shift Key Modulation

Encoding
The simplest and most common form of ASK operates as a switch, using the presence of
a carrier wave to indicate a binary one and its absence to indicate a binary zero. This type
of modulation is called on-off keying, and is used at radio frequencies to transmit Morse
code (referred to as continuous wave operation).
More sophisticated encoding schemes have been developed which represent data in groups
using additional amplitude levels. For instance, a four-level encoding scheme can
represent two bits with each shift in amplitude; an eight-level scheme can represent three
bits; and so on. These forms of amplitude-shift keying require a high signal-to-noise ratio
for their recovery, as by their nature much of the signal is transmitted at reduced power.

5
ASK Modulation & Demodulation Kit

Here is a diagram showing the ideal model for a transmission system using an ASK
modulation:

It can be divided into three blocks. The first one represents the transmitter, the second
one is a linear model of the effects of the channel, the third one shows the structure of the
receiver. The following notation is used:
D h t(t) is the carrier signal for the transmission
D h c(t) is the impulse response of the channel
D n(t) is the noise introduced by the channel
D h r(t) is the filter at the receiver
D L is the number of levels that are used for transmission
D T s is the time between the generation of two symbols
Different symbols are represented with different voltages. If the maximum allowed value
for the voltage is A, then all the possible values are in the range [-A, A] and they are given
by:

the difference between one voltage and the other is:

Considering the picture, the symbols v[n] are generated randomly by the source S, then
the impulse generator creates impulses with an area of v[n]. These impulses are sent to
the filter h to be sent through the channel. In other words, for each symbol a different
t
carrier wave is sent with the relative amplitude.
Out of the transmitter, the signal s(t) can be expressed in the form:

6
 ASK Modulation & Demodulation Kit

In the receiver, after the filtering through h (t) the signal is:
r

where we use the notation:

n (t) = n(t) * h (t)
r r

g(t) = h (t) * h (t) * h (t)

t c r

where * indicates the convolution between two signals. After the A/D conversion the signal
z[k] can be expressed in the form:

In this relationship, the second term represents the symbol to be extracted. The others are
unwanted: the first one is the effect of noise, the second one is due to the inter symbol
interference.
If the filters are chosen so that g(t) will satisfy the Nyquist ISI criterion, then there will be
no intersymbol interference and the value of the sum will be zero, so:
z[k] = n [k] + v[k]g[0]
r

the transmission will be affected only by noise.

Bandwidth Modification
Amplitude shift keying - ASK - in the context of digital communications is a modulation
process, which imparts to a sinusoid two or more discrete amplitude levels. These are
related to the number of levels adopted by the digital message. For a binary message
sequence there are two levels, one of which is typically zero. Thus the modulated wave-
form consists of bursts of a sinusoid. Figure 1 illustrates a binary ASK signal (lower),
together with the binary sequence which initiated it (upper). Neither signal has been band
limited.

Figure-1 : an ASK signal (below) and the message (above)

There are sharp discontinuities shown at the transition points. These result in the signal
having an unnecessarily wide bandwidth. Band limiting is generally introduced before
transmission, in which case these discontinuities would be ‘rounded off’. The band limiting
may be applied to the digital message, or the modulated signal itself.
The data rate is often made a sub-multiple of the carrier frequency. This has been done in
the waveform of Figure-1.

7
ASK Modulation & Demodulation Kit

One of the disadvantages of ASK, when compared with FSK and PSK, for example, is that
it has not got a constant envelope. This makes its processing (e.g., power amplification)
more difficult, since linearity becomes an important factor. However, it does make for ease
of demodulation with an envelope detector.
As already indicated, the sharp discontinuities in the ASK waveform of Figure 1 imply a
wide bandwidth. A significant reduction can be accepted before errors at the receiver
increase unacceptably. This can be brought about by band limiting (pulse shaping) the
message before modulation, or band limiting the ASK signal itself after generation.

Figure - 2

Figure-3 shows the signals present in a model of Figure 2, where the message has been
band limited. The shape, after band limiting, depends naturally enough upon the
amplitude and phase characteristics of the band limiting filter.

Figure-3 : original TTL message (lower), bandlimited message (center),

and ASK (above)

Modeling an ASK Generator

It is possible to model the rather basic generator shown in Figure 2. The switch can be
modeled by one half of a DUAL ANALOG SWITCH module. Being an analog switch, the
carrier frequency would need to be in the audio range. The TTL output from the SEQUENCE
GENERATOR is connected directly to the CONTROL input of the DUAL ANALOG SWITCH.
For a synchronous carrier and message use the 8.333 kHz TTL sample clock (filtered by a
TUNEABLE LPF) and the 2.083 kHz sinusoidal message from the MASTER SIGNALS
module.

8
 ASK Modulation & Demodulation Kit

If you need the TUNEABLE LPF for bandlimiting of the ASK, use the sinusoidal output
from an AUDIO OSCILLATOR as the carrier. For a synchronized message as above, tune
the oscillator close to 8.333 kHz, and lock it there with the sample clock connected to its
SYNCH input.

Intro to Demodulation
It is apparent from Figures 1 and 4 that the ASK signal has a well defined envelope. Thus
it is amenable to demodulation by an envelope detector.
With bandlimiting of the transmitted ASK neither of these demodulation methods
(envelope detection or synchronous demodulation) would recover the original binary
s e q u e n c e ; i n s t e a d , t h e i r o u t p u ts w o u l d b e a b a n d l i m i t e d v e r s i o n . T h u s f u r t h e r
processing - by some sort of decision-making circuitry for example - would be necessary.
Thus demodulation is a two-stage process:
1. recovery of the bandlimited bit stream
2. regeneration of the binary bit stream
Figure 4 illustrates.

Figure-4 : the two stages of the demodulation process

9
ASK Modulation & Demodulation Kit

Carrier Generator
BLOCK DESCRIPTION
4
In BCT – 12, The Carrier frequency of 30 KHz is generated using IC TL084 and IC 8038.
The TL084 series are low-cost, quad operational amplifiers with true differential inputs.
They have several distinct advantages over standard operational amplifier types in single
supply applications. It is specified over a temperature range from -40°C to +85°C. They
have finite differential inputs and remain in the linear mode with an input common – mode
voltage of 0V DC. Both NPN and PNP external current boost transistors can be used to
extend the power capability of the basic amplifiers. Application of this IC is in the circuits
of AC amplifiers, RC active filters, low frequency triangle, square wave and pulse wave-
form generation circuits, tachometers and low speed high voltage digital logic gates.

IC-8038
The XR-8038A is a precision waveform generator IC capable of producing sine, square,
triangular, saw tooth, and pulse waveforms, with a minimum number of external compo-
nents and adjustments. The XR-8038A allows the elimination of the external distortion
adjusting resistor which greatly improves the temperature drift of distortion, as well as
lowering external parts count. Its operating frequency can be selected over eight decades
of frequency, from 0.001Hz to 200kHz, by the choice of external R-C components. The
frequency of oscillation is highly stable over a wide range of temperature and supply volt-
age changes. Both full frequency sweeping as well as smaller frequency variations (FM)
can be accomplished with an external control voltage. Each of the three basic waveform
outputs, (i.e., sine, triangle and square) are simultaneously available from independent
output terminals. The XR-8038A monolithic waveform generator uses advanced process-
ing technology and Scotty-barrier diodes to enhance its frequency performance.

10
Kitek A~~~fu~n&D~o~fu~nM

Data Generator
In BCT -12, IC 555 generates Parallel clock and Serial clock. IC 74165 generates an 8-bit
serial DATA using this Parallel clock and Serial clock
The LM555 is a highly stable device for generating accurate time delays or oscillation.
Additional terminals are provided for triggering or resetting if desired. In the time delay
mode of operation, the time is precisely controlled by one external resistor and capacitor.
For astable operation as an oscillator,
the free running frequency and duty cycle are accurately controlled with two external re-
sistors and one capacitor. The circuit may be triggered and reset on falling waveforms,
and the output circuit can source or sink up to 200mA or drive TTL circuits.

- 8
GNU "Vex
'"
- J
2 1
TRIGGER DISCHARGE

3 6
OUTPUT THRESHOLD

4 5 CONTROL
RESET
VOLTAGE

LM555

The M74HC165 is a high speed CMOS 8 BIT PISO SHIFT REGISTER fabricated with
silicon gate C2MOS technology. This device contains eight clocked master slave RS flip-
flops connected as a shift register, with auxiliary gating to provide over-riding asynchro-
nous parallel entry. Parallel data enters when the shift/load input is low. The parallel data
can change while shiftlload is low, provided that the recommended set-up and hold times
are observed. For clocked operation, shiftlload must be high. The two clock input performs
identically; one can be used as a clock inhibit by applying a high signal; to permit this
operation clocking is accomplished through a 2-input nor gate. To avoid double clocking,
however, the inhibit signal should only go high while the clock is high. Otherwise the rising
inhibit signal will cause the same response as rising clock edge. All inputs are equipped
with protection circuits against static discharge and transient excess voltage.

(LOC II. CLOCI'lINli181T

"
c
PAR"'UE~ IC-74165 PARALlEL
'~PU1!) . INPUTS
\/1
e

GNC GH

11
ASK Modulation & Demodulation Kit

ASK Modulator
In BCT – 12, IC 4066 is the ASK Modulator. The data input is given at Pin No. 13 and the
carrier input is provided at Pin No. 1 of this IC. The modulated output is obtained at Pin
No. 2 of IC 4066
The HCF4066B is a monolithic integrated circuit fabricated in Metal Oxide Semiconductor
technology available in DIP and SOP packages. The HCF4066B is a QUAD BILATERAL
SWITCH intended for the transmission or multiplexing of analog or digital signals. It is pin
for pin compatible with HCF4016B, but exhibits a much lower ON resistance. In addition,
the ON resistance is relatively constant over the full input signal range. The HCF4066B
consists of four independent bilateral switches. A single control signal is required per switch.
Both the p and n device in a given switch are biased ON or OFF simultaneously by the
control signal. As shown in schematic diagram , the well of the n-channel device on each
switch is either tied to the input when the switch is ON or to VSS when the switch is OFF.

IC-4066

ASK De-modulator
In BCT – 12, The ASK De-modulation is done using IC TL084
The TL084 is a quadruple operational amplifier fabricated on a single monolithic chip. It is
specified over a temperature range from -40°C to +85°C. They have finite differential
inputs and remain in the linear mode with an input common – mode voltage of 0V DC. Both
NPN and PNP external current boost transistors can be used to extend the power
capability of the basic amplifiers. Application of this IC is in the circuits of AC amplifiers,
RC active filters, low frequency triangle, square wave and pulse waveform generation
circuits, tachometers and low speed high voltage digital logic gates.

IC-TL084

12
 ASK Modulation & Demodulation Kit

CODE Regenerator
In BCT – 12, The Code Regeneration is done using IC 74164 and IC 74374

The 74HC164 is a high speed CMOS 8 BIT SIPO SHIFT REGISTER fabricated in silicon
gate CMOS technology. It has the same high speed performance of LSTTL combined with
true CMOS low power consumption. The HC164 is an 8 bit shift register with serial data
entry and an output from each of the eight stages. Data is entered serially through one of
two inputs (A or B), either of these inputs can be used as an active high enable for data
entry through the other input. An unused input must be high, or both inputs connected
together. Each low-to-high transition on the clock input shifts data one place to the right
and enters into QA, the logic NAND of the two data inputs (/A. B), the data that existed
before the rising clock edge. A low level on the clear input overrides all other inputs and
clears the register asynchronously, forcing all Q outputs low. All inputs are equipped with
protection circuits against static discharge and transient excess voltage.

IC-74164

The 74F373 is an octal transparent latch coupled to eight 3-State output devices. The two
sections of the device are controlled independently by enable (E) and output enable (OE)
control gates. The data on the D inputs is transferred to the latch outputs when the enable
(E) input is high. The latch remains transparent to the data input while E is high, and
stores the data that is present one setup time before the high-to-low enable transition. The
3-State output buffers are designed to drive heavily loaded 3-State buses, MOS memo-
ries, or MOS microprocessors. The active low output enable (OE) controls all eight 3-State
buffers independent of the latch operation. When OE is low, latched or transparent data
appears at the output. When OE is high, the outputs are in high impedance “off” state,
which means they will neither drive nor load the bus. The 74F374 is an 8-bit edge trig-
gered register coupled to eight 3 - St a t e output b u ff e r s . The two
sections of the device are controlled independently by clock (CP) and output enable (OE)
control gates. The register is fully edge triggered. The state of the D input, one setup time
before the low-to-high clock transition is transferred to the corresponding flip-flop’s Q
output. The 3-State output buffers are designed to drive heavily loaded 3-State buses,

13
ASK Modulation & Demodulation Kit

MOS memories, or MOS microprocessors. The active low output enable (OE) controls all
eight 3-State buffers independent of the register operation. When OE is low, the data in
the register appears at the outputs. When OE is high, the outputs are in high impedance
“off” state, which means they will neither drive nor load the bus.

IC-74373

14
 CODE GENERATOR

D0 TO CRO D0
D1 TO CRO
D2
D3 DATA I/P
D1
D4
D5
D6 DATA D2

1 2 3 4 5 6 7 8
GENERATOR

TP4
D7

TP3
D3

ON

OFF
TP1
D4
PT1 ASK DEMOD

ASK
ASK

15
I/P
CODE DISPLAY

D5

MIN
ASK O/P ASK I/P ASK DMOD

MODULATOR
O/P D6

DEMODULATOR
TP2

ADJUST
CARRIER D7

FREQUENCY
PT3

MAX
EXPERIMENT

GENERATOR

BLOCK DIAGRAM - 1
CARRIER I/P

MIN
10K

TP1 : Test Point for Data Input

ADJUST
TP2 : Test Point for Carrier Input

AMPLITUDE
TP3 : Test Point for ASK Output MIN MAX BCT-12

MAX
TP4 : Test Point for ASK Demod Output
ASK MODULATION &
PT2 ADJUST
DEMODULATION TRAINER
AMPLITUDE SHIFT KEYING MODULATION & DEMODULATION.
5
ASK Modulation & Demodulation Kit
ASK Modulation & Demodulation Kit

AIM OF EXPERIMENT
TO STUDY AMPLITUDE SHIFT KEYING MODULATION & DEMODULATION.

CONCEPT
Digital communication system are system representing the information by the Binary
digits, 1 (one) & (zero). The principles of Digital communication of sampling, multiplexing,
encoding error control coding, data conditioning, carrier modulation etc. There are various
modulation techniques. This kit is for explaining the functions of Frequency shift keying
modulation & demodulation techniques.
In Frequency shift keying (FSK), modulation techniques, the modulated output shift
between two frequencies for all 1(one) & 0(zero) transition. The carrier frequency for FSK
modulation are greater then twice the modulating frequency. The FSK modulator is built
around the 2 to 1 multiplexer which switches between the two signals for all 1(one) to
0(zero) transitions.
FSK demodulator employs PLL logic for the recovery of data. The digital phase locked
loop forms the heart of this logic. The PLL center frequency the lock range are fixed. Thus
the phase detector output at the PLL directly gives the detected data.

PROCEDURE
1. Connect the AC Supply to the Kit
2. Make connections and settings as shown in Block Diagram - 1
3. Select the Data using the DIP switch Provided
4. Connect the DATA output from DATA GENERATOR BLOCK to the ‘DATA Input’ post of
ASK Modulator block
5. Connect one of CARRIER GENERATOR output from CARRIER GENERATOR BLOCK
to the CARRIER INPUT post of ASK Modulator block
6. Switch ON the power
7. Connect the ASK MOD O/P to the ASK MOD I/P of ASK DEMODULATOR section
8. Connect the ASK De-mod O/P to the ASK De-mod I/P of CODE DISPLAY section.
9. The data transmitted will be displayed in LED’S provided
10. Change the DATA I/P using DIP switch provided. Observe the ASK O/P changes ac-
cordingly.
11. Observe the following waveforms on oscilloscope.
a. Carrier Generator O/P.
b. DATA O/P
c. ASK Mod O/P at ASK Modulator.
d. ASK Demodulated signal at ASK DEMOD BLOCK.

16
 ASK Modulation & Demodulation Kit

Fig.-A (Carrier Signal)

Fig.-B (Sample Data)

17
ASK Modulation & Demodulation Kit

Fig.-C (ASK Mod. Output)

Fig.-D (ASK Mod. Output)

18
 ASK Modulation & Demodulation Kit

Fig.-E (ASK Demod. Output)

Fig.-F (ASK Demod. Output)

19
 Z2
R15 R17
R16 C7
AC GND

C3

R18
C6
D1
D3

D2
D4

8038
Tl084
74163
7404
4066
C4
Tl084
C5

10K TRIMP
7812 7912 7805 7905

74164
+ + + + + +

74374
74245
C11 C12 C13 C14 C15 C16

R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13
R14
Z1
74165

C2
10K TRIMP
C1 +
R19

POWER LED

CODE GENERATOR
ASK Modulation & Demodulation Kit

D0 D0
D1
D2
DATA I/P

20
D3 D1
D4 TP4
D5 TP3
D6 DATA D2
D7 GENERATOR
OFF ON D3
TP1
D4
PT1 ASK DEMOD

ASK
ASK

I/P
CODE DISPLAY

D5

MIN
ASK O/P ASK I/P ASK DMOD

MODULATOR
O/P D6
DEMODULATOR

100K TP2

ADJUST
CARRIER D7

FREQUENCY
PT3

MAX
GENERATOR
CARRIER I/P

MIN
10K
100K
TP1 : Test Point for Data Input

ADJUST
TP2 : Test Point for Carrier Input

AMPLITUDE
TP3 : Test Point for ASK Output MIN MAX BCT-12

MAX
TP4 : Test Point for ASK Demod Output
ASK MODULATION &
PT2 ADJUST
DEMODULATION TRAINER
 ASK Modulation & Demodulation Kit

Table of Contents

1 SPECIFICATION ..................................................................................... 1

2 INTRODUCTION .................................................................................. 2-3

3 CONCEPT OF TDM MODULATION .................................................... 4-9

4 BLOCK DESCRIPTION ................................................................... 10-14

5 EXPERIMENT .................................................................................. 15-19

BLOCK DIAGRAM ............................................................................... 20

21
i
 WARRANTY / CERTIFICATE

KITEK Technologies product are warranted against any defects in workmanship

and meterials. Any such failure will corrected free of cost or replaced within war-
ranty period. D e f e c t i v e p r o d u c ts i s o n K I T E K Te c h n o l o g i e s s o l e
judgement.

The warranty does not apply on any Improper or Inadequate Maintenance, Mishan-
dling, Incidental Damages, Transit Damages, Natural Disaster. There will be no
warranty on Acessories.

In the warranty period if the service is needed, purchaser should get in touch with
the authorised sales/service centers.

Customer Name :

Model No. :

Serial No. :

Date :

Distributor Name :

Warranty :

Seal & Signature