The document discusses baseband and modulated communication signals. It defines baseband signals as those that do not use modulation and transmit information in its original form within the baseband frequency range. Modulated signals use carrier waves to shift the information signal to higher frequencies suitable for transmission. The key types of modulation discussed are amplitude modulation (AM), which varies the amplitude of the carrier wave, and angle modulation including frequency modulation (FM) and phase modulation (PM), which vary the frequency or phase of the carrier. Common applications of baseband signals include telephony and digital data transmission over copper wires, while modulated signals are required for wireless transmission through free space using radio frequencies.

2.  BASEBAND COMMUNICATION:
 Communication that does not use modulation
(transmits information in its original form)
 No shift in the range of frequencies of the signal.
 The term baseband is used to designate the band of frequencies
of the signal delivered by the source
Telephony: Baseband is the audio band (band of voice signals) occupying
0 – 3.5kHz
Television: Baseband is the video band (band of video signals) occupying 0
– 4.3 MHz
Digital data/PCM (A-to-D conversion):Using bipolar signaling at a rate of
Rb pulses/sec, the baseband is 0 - Rb Hz

3.  Pulse modulated signals such as:
 PAM (Pulse Amplitude Modulation)
 PWM (Pulse Width Modulation)
 PPM (Pulse Position Modulation)
 PCM (Pulse Code Modulation)
Principle of PAM: (1) original signal, (2) PAM signal,
(a) amplitude of signal, (b) time
Despite the term modulation, the above signals are baseband coding
schemes and they yield baseband signals

4.  Baseband signals have sizable power at low frequencies
 Baseband signals cannot be transmitted over a radio link (free space)
 Baseband signals are suitable for transmission over copper (pair of
wires, coaxial cable) or glass (fiber).
 Examples:
 Local telephone communication
 Short-haul PCM communication (between local exchanges)

5.  Communication that uses modulation to shift the frequency
spectrum of a signal
 Modulation is used when it is impractical to propagate low-
frequency baseband signals over free space
 Modulation uses high frequency carriers to achieve simultaneous
transmission with no interference (multiplexing of various signals)
 AM, FM, PM, FSK, PSK, QAM

6.  Modulation is the process of varying one or more
properties of a high-frequency periodic waveform, called
the carrier signal, with a modulating signal which
typically contains information to be transmitted.
 The three key parameters of a periodic waveform are its
amplitude (volume), its phase (timing) and its
frequency (pitch).
 Modulation is the process of conveying a message
signal, for example a digital bit stream or an analog audio
signal, inside another signal that can be physically
transmitted.

7.  Modulation of a sine waveform is used to transform a
baseband message into a passband signal, for example low-
frequency audio signal into a radio-frequency signal (RF
signal)

8.  Short Operating Range – When a wave has a large frequency, the energy associated
with it will also be large. Thus low frequency signals have less power that does not
enable them to travel over long distances.
 Poor Radiation Efficiency – The radiation efficiency becomes very poor for low
frequency signals.
 Mutual Interference – If all audio frequencies are send continuously from different
sources, they would all get mixed up and cause erroneous interference air. If
modulation is done, each signal will occupy different frequency levels and can be
transmitted simultaneously without any error.
 Huge Antenna Requirement – For a effective signal transmission, the sending and
receiving antenna should be at least 1/4th
of the wave length of the signal. Thus, for
small frequencies, the antenna will have kilometres of length. But if the signal has the
range of MegaHertz frequency, then the antenna size would be less.
 The carrier wave cannot be used alone for transmission purposes. Since its
amplitude, frequency, and phase angle are constant with respect to some preference.

9.  The technique of superimposing the message
signal on the carrier is known as modulation.
 That is, modulation is the process by which a
parameter of one signal (carrier) is varied in
proportion to the second signal (message signal).
 Let m(t) = message (or information) signal
c(t) = carrier signal
s(t) = modulated signal (transmitted signal)
m(t) S(t)
Modulated signalModulator
c(t)

10.  The carrier c(t) is a pure sinusoidal signal generally given as
 Examination of c(t) indicate that there are 3 parameters which may be varied:
◦ Amplitude
◦ Frequency
◦ Phase
 These parameters can be varied in Analog or Digital form. When varied in digital
form, it is referred to as “Shifting and Keying”

11.  Analog Modulation
 The aim of analog modulation is to transfer an analog baseband signal, for
example an audio or TV signal, over an analog bandpass channel at a different
frequency (over a limited radio frequency band or cable TV network channel).
 Using the message signal to vary amplitude, frequency, phase leads to three
basic types of analog modulation schemes respectively known as
◦ Amplitude Modulation
◦ Frequency Modulation
◦ Phase Modulation
 These types of modulation are carrier/continuous wave modulation.
 Frequency and Phase Modulation are also known as Angle Modulation

13.  Amplitude Modulation (AM) is a technique used in electronic communication
for transmitting information using radio waves in which the amplitude of the carrier
wave is varied in accordance with the amplitude of the information signal.
 Amplitude Modulation is used whenever a shift in the frequency components of a
given signal is desired.
◦ E.g., transmitting voice signal (3 kHz) through electromagnetic wave requires that 3 kHz
be raised several orders of magnitude before transmission.
 If the two modulated signals are sinusoidal, the beat frequencies will be the sum
and the difference of the original frequencies.
 AM radio broadcast transmissions contain two signals of primary importance to
the user: the carrier signal and the audio signal, or the program signal.

14.  The carrier frequency is the frequency to which the radio receiver is tuned for
station selection.
 For example, the AM radio band (broadcast band) is legally designated from 535
to 1605 kHz.
 If your favorite local radio station broadcasts on 830 kHz, this means that the
carrier frequency being used for transmission is 830 kHz.
 The audio or program signal is riding on this carrier frequency.

15.  Amplitude Modulation (AM) is the oldest method of transmitting human
voice electronically.
 In an analog telephone conversation, the voice waves on both sides
are modulating the voltage of the direct current loop connected to
them by the telephone company.
 Amplitude Modulation (AM) is also widely used to alter a carrier wave
to transmit data.
 For example, in AM radio, the voltage (amplitude) of a carrier with a
fixed center frequency (the station’s channel) is varied (modulated) by
the analog audio signal.

16.  Amplitude Modulation Applications:
 AM radio Broadcasting
 TV picture (video)
 Two way radio
 Aircraft
 Amateur radio (SSB)
 Citizen’s band radio
 Military communication
 Digital data transmission
 Computer Modems (used in combination with phase modulation QAM)
 NIST Time Signals

19.  The amplitude of high-carrier signal is varied
according to the instantaneous amplitude of the
modulating message signal m(t).
Carrier Signal: or
Modulating Message Signal: or
The AM Signal:
cos(2 ) cos( )
( ) : cos(2 ) cos( )
( ) [ ( )]cos(2 )
c c
m m
AM c c
f t t
m t f t t
s t A m t f t
π ω
π ω
π= +

20.  Mathematical expression for AM: time domain
 expanding this produces:
 In the frequency domain this gives:
( ) (1 cos ) cosAM m cS t k t tω ω= +
( ) cos cos cosc cAM mS t t k t tω ω ω= +
[ ])cos()cos(coscos:using 2
1 BABABA ++−=
2 2( ) cos cos( ) cos( )c c c
k k
AM m mS t t t tω ω ω ω ω= + − + +
frequency
k/2
k/2
Carrier, A=1.
upper sideband
lower
sideband
Amplitude
fcfc-fm fc+fm

34. Suppose that Vmax value read from
the graticule of the oscilloscope is 4.6
divisions and Vmin is 0.7 divisions.
What will be the Modulation Index?

35. 4.6-0.7
4.6+0.7
m =
3.9
4.5
=
= 0.736

39. Modulation Index of AM SignalModulation Index of AM Signal

40. Modulation Index of AM SignalModulation Index of AM Signal

41. Modulation Index of AM SignalModulation Index of AM Signal

42.  When the modulation of the amplitude modulated signal exceeds
100% it results into overmodulation.
 At this point the carrier breaks up and intermodulation distortion
occurs leading to large levels of unwanted noise spreading out
either side of the carrier and beyond the normal bandwidth.
 If over-modulation occurs, the carrier becomes phase inverted and
this leads to sidebands spreading out either side of the carrier.

44. SIDEBANDS IN AM

49.  There are four kinds of Amplitude Modulation techniques namely;
 Conventional Amplitude Modulation
◦  Carrier + Upper Sideband + Lower Sideband
 Double Sideband Modulation (DSB) – Suppressed Carrier (SC)/Reduced Carrier
(RC)
◦  Upper Sideband + Lower Sideband
 Single Sideband Modulation (SSB)
◦  Only one Sideband (Upper or Lower)
 Vestigial Sideband (VSB)
◦  Upper Sideband + portions of the Lower Sideband

52. Modulation
• This type of modulation shifts the spectrum of m(t) to the carrier frequency.
If
)()( wMtm ⇔
[ ])()(
2
1
cos)( ccc wwMwwMtwtm −++⇔

53. 53
Demodulation
• The process of receiving the original signal from the modulated signal is
called demodulation.
• Demodulation is similar to modulation and can be performed by
multiplying the modulated signal again with the carrier signal
[ ])2cos()()(
2
12cos)()( t
c
wtmtmt
c
wtmte +==
[ ])2()2(
4
1)(
2
1)( cc
wwMwwMwMwE −+++=

54.  The method of recovering the baseband signal
wherein we use a carrier of exactly the same
frequency (or phase) as the carrier used for
modulation is called as synchronous detection or
coherent detection.

55. • MESSAGE SIGNAL =
• CARRIER SIGNAL =
• MODULATED SIGNAL =
DOUBLE SIDEBAND MODULATION SUPPRESSED CARRIER (DSB-SC)
)(cos)( ωω MtEtm mm ↔=
)(cos)( ωω CtEtC cc ↔=
ttEEtCtm cmcm ωω coscos)()( =
[ ]tt
EE
mcmc
cm
)cos()cos(
2
ωωωω −++
[ ])()(
2
cos)( mcmc
cm
c MM
EE
ttm ωωωωω −++↔
fπω 2= )cos(
2
1
)cos(
2
1
))(cos(cos YXYXYX −++=

56. DOUBLE SIDEBAND MODULATION SUPPRESSED CARRIER (DSB-SC)
ttm mωcos)( =
ttC cωcos)( =
)()( tCtm
[ ]tt
EE
mcmc
cm
)cos()cos(
2
ωωωω −++
MULTIPLIER
MODULATOR

58.  An example of message, carrier, and DSB-SC modulated signals

59. DOUBLE-SIDEBAND SUPPRESS CARRIER (DSB-SC)DOUBLE-SIDEBAND SUPPRESS CARRIER (DSB-SC)
)(ωM
MESSAGE
)(ωDSBM
MODULATED SIGNAL
(DSB-SC AM)
BANDWITH:
mmf ωπ =2mω−
mm fB =
cω mc ωω +mc ωω −cω mc ωω +mc ωω −
USBLSB
mB
0
0
mBmB
mBB 2=BW OF THE MODULATED SIGNAL IS:

60. DOUBLE-SIDEBAND SUPPRESS CARRIER (DSB-SC)DOUBLE-SIDEBAND SUPPRESS CARRIER (DSB-SC)
THE MODULATED CARRIER SPECTRUM CENTERED
AT fc IS COMPOSED OF AN UPPER SIDEBAND ABOVE
fc, (USB), AND A LOWER SIDEBAND BELOW fc, (LSB).
USBLSB
2 fm
[ ]tt
EE
mcmc
cm
)cos()cos(
2
ωωωω −++
MODULATED SIGNAL DOES NOT HAVE A COMPONENT AT fc, IN
THIS CASE THE SCHEME IS CALLED DSB-SC MODULATION

61.  The carrier component in full AM or DSB-LC does not convey any information.
Hence it may be removed or suppressed during the modulation process to attain
higher power efficiency.
 The trade off of achieving a higher power efficiency using DSB-SC is at the expense
of requiring a complex and expensive receiver due to the absence of carrier in order
to maintain transmitter/receiver synchronization.
Double Side Band Suppressed
Carrier
(DSB-SC) Modulation

62.  A device that performs modulation is known as a modulator
Multiplier Modulators
Modulation is achieved directly by multiplying m(t) with cosωct using
an analog multiplier whose output is proportional to the product of
two signals
The use of multipliers is generally undesirable for two main reasons: expensive
and have linearity problems

63.  Modulation is achieved by using nonlinear devices such as diodes
or a transistor.
Two nonlinear identical elements are used shown by boxes marked NL

64. These signals are passed through two exactly similar non–linear devices that scale the
input signals and add it to a scaled version of the square of their input signals.

65. The sum (or actually the different) of the outputs of the two non–linear devices
contains two terms that can be described as follows:

66.  Advantages:
- Lower power consumption
66
 Disadvantage:
- Complex detection
 Applications:
- Analogue TV systems: to transmit colour
information
- For transmitting stereo information in FM sound
broadcast at VHF

67. For DSB-SC a receiver must generate a carrier in frequency and phase
synchronism with the carrier at the transmitter.
Problem:
Transmitter and receiver may be located thousands of miles away, this calls
for a sophisticated receiver and could be costly.
Solution:
Transmit a carrier Acoswct along with the modulated signal m(t)coswct so no
need to generate a carrier at the receiver.

68. This type of modulation is called amplitude modulation and denoted by
and is given by:
)(tAMϕ
It has the Fourier spectrum
The spectrum of is the same as m(t) coswct plus two additional
impulses at
)(tAM
ϕ
cw±
•DSB-SC signal m(t) coswct and AM signal are identical with
A+m(t) as modulating signal instead of m(t)
•To sketch ,we sketch A+m(t) & -(A+m(t) ) and fill in between the
carrier frequency.
)(tAM
ϕ

69. As we sketch A+m(t) & -(A+m(t) ):
Consider two cases:
0)( ≥+ tmA and 0)( ≤+ tmA

70. For simple envelope detection for AM signal is:
A = 0, also satisfies the condition. In this case there is no need to add
carrier, because the envelope of DSB-SC signal m(t) coswct is m(t)
Such a DSB-SC signal can be detected by envelope detection
Assume for all t
Let mp is the peak amplitude (positive or negative) of m(t)
Then Hence the condition is equivalent to
Thus the minimum carrier amplitude required for the envelope
detection is mp

71. We define the modulation index as:µ
A = carrier
amplitude
mp = constant of
m(t)
As A is the carrier amplitude and there is no
upper bound on A,
This is the condition for the viability of demodulation of AM signal by an
envelope detector

72. This case is referred to as tone modulation because the
modulating signal is a pure sinusoid

73.  In AM, the carrier term does not carry any information, hence carrier
power is wasted.
The total power is the sum of carrier (wasted) power and the sideband
(usable) power.
Power efficiency is given by

74. Determine power efficiency η and the
percentage of total power carried
by the sidebands of the AM wave
for tone modulation when
a) µ= 0.5
b) µ= 0.3

76. Purpose :
 To reduce the bandwidth requirement of AM by
one-half.
 This is achieved by transmitting only the upper
sideband or the lower sideband of the DSB AM
signal.

79.  A DSB-SCDSB-SC AM signal required a channel bandwidth of
BBcc =2=2WW for transmission, where WW is the bandwidth of the
message signal.
 We reduce the bandwidth of the transmitted signal to that
of the baseband message signal m(t).
µ( ) ( )cos2 ( )sin 2c c c cu t A m t f t A m t f tπ π= m
the Hilbert transform of m(t)
lower sideband
upper sideband

80. )(M ω
0 B2πB2π−
cωcω−
SSB (Upper sideband)
→ω
→ω
→ω
0
0
cωcω−
)(SSB ωΦ
Baseband
DSB
SSB

81. HL(t)=1/2[sgn(f+fc)-sgn(f-fc)]
XDSB(f)=1/2AC[M(f+fc)+M(f-fc)]
XSSB(f)=1/4AC[M(f+fc) sgn(f+fc)]+M(f-fc)sgn(f+fc)]-
1/4AC[M(f+fc) sgn(f-fc) +[M(f-fc) sgn(f-fc)]
= 1/4AC[M(f+fc)+M(f-fc)]+ 1/4AC[M(f+fc) sgn(f+fc)]-
M(f-fc)sgn(f-fc)]
=1/2AC m(t)cosωct 1/4[M(f+fc)+M(f-fc)]

82. Hilbert Transform
(t) -jsgnf M(f)
m(t)e±j2Πfct
M(f fc)
m(t)e±2Πfct
-j M(f fc)sgn(f fc)
j-1
{1/4AC[M(f+fc)sgn(f+fc)]-M(f-fc)sgn(f-fc)]}
=-AC1/4j (t) e-j2Πfct
+ AC1/4j (t) e2Πfct
=1/2Acb (t)sin2Πfct
XSSB(f)=1/2AC m(t)cosωct+ 1/2Ac (t)sinωct

83.  Hilbert transform may be viewed as a linearlinear
filterfilter with impulse response
( ) 1/h t tπ=
and frequency responsefrequency response
, 0
( ) , 0
0, 0
j f
H f j f
f
− >

= <
 =
With phase shift
π/2

84. Generation of aGeneration of a
lower single-lower single-
sideband AM signalsideband AM signal
Generation of a single-Generation of a single-
sideband AM signal bysideband AM signal by
filtering one of thefiltering one of the
sidebands of a DSB-sidebands of a DSB-
SCAM signal.SCAM signal.

85. SSB Signals
◦ SSB signals offer four major benefits:
1. Spectrum space is conserved and allows more signals to
be transmitted in the same frequency range.
2. All power is channeled into a single sideband. This
produces a stronger signal that will carry farther and will
be more reliably received at greater distances.
3. Occupied bandwidth space is narrower and noise in the
signal is reduced.
4. There is less selective fading over long distances.

87.  Vestigial Sideband (VSB)  Upper Sideband + portions of the Lower Sideband
 A vestigial sideband is a sideband that has been only partly cutoff or suppressed.
 Television broadcasts (in analog video formats) use this method if the video is
transmitted in AM, due to large bandwidth used.
 It may also be used in digital transmission, such as the ATSC standardized 8-VSB.
 The video baseband signal used in TV in countries that use NTSC or ATSC has a
bandwidth of 6 MHz.
 To conserve bandwidth, SSB would be desirable, but the video signal has significant
low frequency content (avg brightness) and has rectangular synchronizing pulses. The
engineering compromise is VSB modulation.

94.  Vestigial Sideband Modulation
Instead of transmitting only one sideband as SSB,
VSB modulation transmits a partially suppressed
sideband and a vestige of the other sideband.
Vestigial Side Band Modulation
(VSB)

95. DSB-SC
- Less transmitted power than full AM and all the
transmitted power is useful.
- Requires a coherent carrier at the receiver; This results
in increased complexity in the detector(i.e.
synchroniser)
- Suited for point to point communication involving one
transmitter and one receiver which would justify the use
of increased receiver complexity.
Comparison of Amplitude Modulation
methods

96. SSB
- Good bandwidth utilization (message signal
bandwidth = modulated signal bandwidth)
- Good power efficiency
- Demodulation is harder as compared to full AM;
Exact filter design and coherent demodulation are
required
- Preferred in long distance transmission of voice
signals
Comparison of Amplitude Modulation
methods

97. VSB
- Offers a compromise between SSB and DSB-SC
- VSB is standard for transmission of TV and similar
signals
- Bandwidth saving can be significant if modulating
signals are of large bandwidth as in TV and wide
band data signals.
 For example with TV the bandwidth of the
modulating signal can extend up to 5.5MHz; with full
AM the bandwidth required is 11MHz
Comparison of Amplitude Modulation
methods

100.  For the purpose of synchronous demodulation, a
local carrier must be generated at the receiver.
 It should be in frequency and phase synchronism
with the incoming carrier.
 Any discrepancy in the frequency or phase of the
local carrier gives rise to distortion in the detector
output.

102. O/P is proportional to m(t) when δ is constant
O/P maximum when δ=0 and minimum when δ = ± π/2
Phase error δ may vary directly with time (variations in propagation path)
Gain factor Cos δ at the receiver varies randomly and is undesirable.
The output is an attenuated replica of the incoming signal and distorted
Δω is small, o/p of m(t) is multiplied by low frequency sinusoid
Amplitude varies from maximum to zero periodically at twice the period of beat
frequency Δω

103.  Useful device for synchronous demodulation of AM signals with
suppressed carrier or with a little carrier (the pilot)
 Track the phase and frequency of the carrier component of an
incoming signal
 Also used for demodulation of angle modulated signals under low
SNR conditions.
 Space vehicle to earth data links and where loss along the
transmission path is higher
 Commercial FM receivers

105.  Phase Detector
 Acts as comparator
 Produces a voltage proportional to the phase difference
between input and output signal
 Voltage becomes a control signal
The phase comparator generates an output voltage x(t)(relates toThe phase comparator generates an output voltage x(t)(relates to
the phase difference between of external signalthe phase difference between of external signal
and and VCO outputand and VCO output

106. •If the two frequencies are the same (with aIf the two frequencies are the same (with a
pre-defined phase difference) THENpre-defined phase difference) THEN x(t) = 0x(t) = 0
• If the two frequencies are not equal (withIf the two frequencies are not equal (with
various phase differences), THENvarious phase differences), THEN x(t) = 0x(t) = 0 andand
with frequency components about twicewith frequency components about twice
the input frequencythe input frequency

107.  Voltage Controlled Oscillator
An oscillator whose frequency can be controlled by an external voltage
Oscillator frequency varies linearly with input voltage
If VCO input voltage is eot, its o/p is a sinusoid of frequency ω given by
 Set tuning range
 Set noise margin
 Creates low noise clock oscillation

109. PLL LOCK RANGEPLL LOCK RANGE
• LOCK RANGELOCK RANGE IS DEFINED AS THE RANGE OFIS DEFINED AS THE RANGE OF
FREQUENCIES IN THE VICINITY OF THE VCO’sFREQUENCIES IN THE VICINITY OF THE VCO’s
NATURAL FREQUENCY (FREE-RUNNING FREQUENCY)NATURAL FREQUENCY (FREE-RUNNING FREQUENCY)
FOR WHICH THE PLL CAN MAINTAINFOR WHICH THE PLL CAN MAINTAIN LOCKLOCK WITHWITH
THE INPUT SIGNALTHE INPUT SIGNAL
• THE LOCK RANGE IS ALSO CALLED THETHE LOCK RANGE IS ALSO CALLED THE TRACKINGTRACKING
RANGERANGE
• THE LOCK RANGE IS A FUNCTION OF THE TRANSFERTHE LOCK RANGE IS A FUNCTION OF THE TRANSFER
FUNCTIONS OF THE PC, AMPLIFIER, AND VCOFUNCTIONS OF THE PC, AMPLIFIER, AND VCO

110. PLL LOCK RANGEPLL LOCK RANGE
• THETHE HOLD-IN RANGEHOLD-IN RANGE IS EQUAL TO HALF THE LOCKIS EQUAL TO HALF THE LOCK
RANGERANGE
• THE LOWEST FREQUENCY THAT THE PLL WILL TRACKTHE LOWEST FREQUENCY THAT THE PLL WILL TRACK
IS CALLED THEIS CALLED THE LOWER LOCK LIMITLOWER LOCK LIMIT
• THE HIGHEST FREQUENCY THAT THE PLL WILL TRACKTHE HIGHEST FREQUENCY THAT THE PLL WILL TRACK
IS CALLED THEIS CALLED THE UPPER LOCK LIMITUPPER LOCK LIMIT

111. PLL LOCK RANGEPLL LOCK RANGE

112. PLL CAPTURE RANGEPLL CAPTURE RANGE
• CAPTURE RANGECAPTURE RANGE IS DEFINED AS THE BAND OFIS DEFINED AS THE BAND OF
FREQUENCIES IN THE VICINITY OF fo WHERE THEFREQUENCIES IN THE VICINITY OF fo WHERE THE
PLL CAN ESTABLISH OR ACQUIRE LOCK WITH ANPLL CAN ESTABLISH OR ACQUIRE LOCK WITH AN
INPUT RANGE (ALSO CALLED THE ACQUISITIONINPUT RANGE (ALSO CALLED THE ACQUISITION
RANGE)RANGE)
• CAPTURE RANGE IS A FUNCTION OF THE BW OF THECAPTURE RANGE IS A FUNCTION OF THE BW OF THE
LPF ( LPF BW CAPTURE RANGE)LPF ( LPF BW CAPTURE RANGE)
• CAPTURE RANGE IS BETWEEN 1.1 AND 1.7 TIMES THECAPTURE RANGE IS BETWEEN 1.1 AND 1.7 TIMES THE
NATURAL FREQUENCY OF THE VCONATURAL FREQUENCY OF THE VCO

113. PLL CAPTURE RANGEPLL CAPTURE RANGE
• THE PULL-IN RANGETHE PULL-IN RANGE IS EQUAL TO HALF THEIS EQUAL TO HALF THE
CAPTURE RANGECAPTURE RANGE
• THE LOWEST FREQUENCY THAT THE PLL CAN LOCKTHE LOWEST FREQUENCY THAT THE PLL CAN LOCK
ONTO IS CALLED THE LOWER CAPTURE LIMITONTO IS CALLED THE LOWER CAPTURE LIMIT
• THE HIGHEST FREQUENCY THAT THE PLL CAN LOCKTHE HIGHEST FREQUENCY THAT THE PLL CAN LOCK
ONTO IS CALLED THE UPPER CAPTURE LIMITONTO IS CALLED THE UPPER CAPTURE LIMIT

114. Fall 2001ENZO PATERNO 114
PLL CAPTURE RANGEPLL CAPTURE RANGE

115. PLL LOCK/CAPTURE RANGEPLL LOCK/CAPTURE RANGE
LOCK RANGE > CAPTURE RANGELOCK RANGE > CAPTURE RANGE