comprehensive viva voce ppt

Comprehensive Viva-Voce

Under the Guidance of Mr.R Kiran Rao, M.Tech Asst.Professor

Presented BySrishti.P

08E31C0489IVth Year, ECE-B

Contents

Analog Communication

Sampling Theorem

Pulse Amplitude Modulation

Pulse Position Modulation

Pulse Width Modulation

Pulse And Digital Circuits High Pass Filter

Low Pass Filter

Attenuator

Clampers

Contents

Electronic Devices And Circuits

Forces ,Fields ,Electric Potential, Intensity.

PN Junction

Different types of Diodes

Rectifiers

Cellular And Mobile Communication

Frequency Management

Set-up Channels

Channel Assignment

Handoff

Analog Communication

Sampling Theorem

“A continuous-time signal may be completely represented in finite samples and recovered back if the sampling frequency is fs> 2fm”

Pulse Amplitude Modulation

Demodulation of PAM

Pulse Position Modulation

Demodulation Of PPM

Pulse Width Modulation

Modulation OF PWM

Demodulation Of PWM

Comparison of PAM ,PPM,PWM

Pulse And Digital Circuits

HIGH PASS RC CIRCUIT

The circuit which attenuates low frequency signals and transmits only high frequency signals is called a high pass circuit.

Sinusoidal Input

Step Input

Ramp Input

Pulse Input

Square-Wave Input

LOW PASS RC CIRCUIT

A low pass RC circuit is a circuit, which transmits only low frequency signals and attenuates or stops high frequency signals.

Sinusoidal Input

Step Voltage Input

Pulse Input

Square Wave Input

ATTANUATORS

A circuit which reduces the amplitude of the input signal is called as the attenuator.

NON-LINEAR WAVE SHAPING

“The process where by the form of a sinusoidal or non-sinusoidal signal is altered by transmitting through a non-linear network is called as non-linear wave shaping”.

CLAMPER CIRCUITS

Clamping is a process of introducing a dc level into a signal.

NEGATIVE DIODE CLAMPER

POSITIVE CLAMPER

Voltage Doubler

Charged Particles

Electronic Devices and Circuits

Field Intensity E

The electric field intensity can be defined as the force per charge on the test charge.

Electric Potential Due to Point Charge

Electric Potential at a point P= work done in bringing a point charge from infinity to point P

Force and Motion in Magnetic Field

The PN junction

Formation of Depletion Layer

Forward Biasing of PN Junction Diode

Reverse Biasing of PN Junction Diode

HALF-WAVE RECTIFIER

FULL WAVE RECTIFIER ( FWR )

Cellular and Mobile CommunicationsFrequency Management

The function of frequency management is to divide the total number of available channels into subsets which can be assigned to each cell either in a fixed fashion or dynamically.

Numbering the channels and Grouping into subsets

• The total number of channels is 666 channels. A channel consists of two frequency channel bandwidths, one in the low band and one in the high band.

• The 666 channels are divided into two groups: block A system and block B system.

• Each block has 333 channels. The 42 set-up channels are assigned as follows: Channels 313-333 block A Channels 334-354 block B

• The number of voice channels for each system 312. Since there are 21 set-up channels for each system

Channel Assignment

In a fixed channel assignment there are two types of channels assigned: set up Channels and Voice Channels.

Set-up channels

There are 21 set-up channels assigned each cell in a K = 4, K=7,or K = 12 frequency-reuse pattern.

Voice channels

One way of dividing the total voice channels into 21 sets. The assignment of certain sets of voice channels in each cell site is based on causing minimum co-channel and adjacent-channel interference.

Fixed Channel Assignment

Adjacent-channel assignment

Channel sharing and borrowing

HANDOFF

Handoff Initiation

Intersystem handoff

Cell site handoff scheme

Dropped calls

The definition of a dropped call is after the call is established but before it is properly terminated. The definition of “the call is established” means that the call is setup completely by the setup channel

The perception of dropped call rate by the subscribers can be higher due to:

1. The subscriber unit not functioning properly (needs repair).

2. The user operating the portable unit in a vehicle (misused).

3. The user not knowing how to get the best reception from a portable unit

(needs education).