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Contents 

1- Short history of recording - - - - - - 3 

  In modern era - - - - - - 4 

2- Studio designing - - - - - - 5 

  Studio - - - - - - 5 

  Booth - - - - - - 5   Sound track  - - - - - - 5 

  FM studio - - - - - - 6 

  MCR (main control room) - - - - - - 6 

3- Radio broadcasting stations - - - - - - 7 

  AM - - - - - - 7 

  FM - - - - - - 8 

  SW (short wave) - - - - - - 8 

4- Transmission medium - - - - - - 9 5- Transmitter - - - - - - 10 

6- Satellite communications - - - - - - 11 

  Introduction - - - - - - 11 

  Basic elements - - - - - - 11 

  The satellite - - - - - - 11 

  The ground station - - - - - - 11 

  Various uses of satellite communication - - - 11 

7-  SINPO - - - - - -  12 

  S (signal strength) - - - - - - 12 

  I (interference) - - - - - - 12 

  N (noise) - - - - - - 12 

  P (propagation) - - - - - - 12 

  O (overall limit) - - - - - - 12 

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15 days Internship in the month of january, in

GROUP MEMBERS OF INTERNIES

Names Roll #

 

 

 

 

 

Remarks by internies

Approved by Azeemullah Hashmi, Engineer Manager.

Remarks by interni co-ordinator(s),

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SHORT HISTORY OF RECORDING 

In old age there is concept of recording, only people listen live. 1st recording is on the stone,

after this this is enhanced by on metal wire recording. The first wire recorder was

a Valdemar Poulsen Telegraphone of the late 1890s.

It is process by the electrical working into mechanical working to produce sound energy to

listen by peoples.

 A coil of wire(voice coil) is placed (inside the cone) in magnetic field produced by a strong

permanent magnet. The signal to converted is applied to the coil, so a magntic field is

produced due to electric current in the coil. The coil system and permanent magnetic field

interacts, so mechanical motion is produced and it causes the coil to move to&fro and it

touches the cone, therby reproducing sound from the electrical signal. 

A nominal speed of 24 inches per second (610 mm/s).

At 50 Hz of electricity. 

Magnetic tape is of Ferrous oxide FeO2. 

Making a typical one-hour spool of wire 7,200 feet (approx. 2200 m) long. 

Old equipments, 

HISTORY OF 

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IN MODERN ERA

Now a days in a modern era the technology is vast, now recording is on CD’s, DVD’s,

Computer data base, digital devices, softwares etc.

  When computer technology evolved to the state where this digital audio could be

recorded onto a hard disk the system came into its own.

  Only when personal computers and networks with central servers became powerful

enough to handle large amounts of audio (and pump it round a large building) did

digital audio really come into its own for broadcasting.

For more detail on wire recording,

Link: http://www.videointerchange.com/wire_recorder1.htm 

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STUDIO DESIGNING

Studio designing is an important part of radio station. In studios live and recorded programs

are made. There are different studios for different types of program. Commonly a studio

consist of three rooms:

Studio

Sound lock

Booth

1. Studio

Studio consists of sound proofing system so that echo effect can be neglected. This is

called acoustic treatment. It consist of table and chairs and several microphones. There is

also a speaker and a light showing that the program is ON AIR or not .People belonging toprogram sit here.

2. Booth

It has all the connections of microphones and speaker of the studio room and are

connected to a console. A console is a device which is used to control all the other devices.

There is a gramophone, cassette recorder, tape recorder, CD/DVD recorder, computer and

etc. These all are also connected with console. Console is also connected with

MCR(Master Control room) and with other studios. It is operated by an engineer.

3. Sound lock

It works as sound barrier between studio and booth.

DESIGNING OF 

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FM Studio

FM studios may have a single room studio in which all the items of a Studio and booth arepresent. Its operator and programmer is a single person known as RJ.

Master Control Room (MCR)

 All the studios in a radio station are connected to a room called master control room. This

room decides which studio should go ON AIR and which do not. It has all the studios input

and ouput pins. It works like a communicator between studios. MCR also consist of 

connections of transmitter and receiver. MCR decides which program should go ON AIR.

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RADIO BROADCASTING STATIONS

Radio broadcasting is a one-way wireless transmission over radio waves intended to reach

a wide audience. Stations can be linked in radio networksto broadcast a common radio

format, either in broadcast syndication or simulcast or both. Audio broadcasting also can be

done via cable radio, local wire television networks, satellite radio, and internet

radio via streaming media on the Internet. The signal types can be either analog

audio or digital audio. 

TV audio transmission frequency is 65 Mhz to 72 Mhz.

1- AM

In AM waves are travel with respect to the ground. The power in AM waves is 1kw to

10,000 kw. 

AM refers to amplitude modulation, a mode of broadcasting radio waves by varying

the amplitude.

AM is that its signal can be detected (turned into sound) with simple equipment. If a

signal is strong enough, not even a power source is needed.

AM radio transmitters can transmit audio frequencies up to 15 kHz. 

AM broadcast can meet or exceed the 15 kHz baseband bandwidth alloted

to FM stations without objectionable interference.

It generates audio signal on carrier by grounding the RF and pass by AM audio.

BROADCASTING 

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2- FM

FM refers to frequency modulation, and occurs on VHF airwaves in the frequency

range of 88 to 108 MHz. 

 But Japan uses the 76 to 90 MHz band. Russia has two bands, 65.9 to

74 MHz  FM stations are much more popular since higher sound fidelity

and stereo broadcasting became common in this format.

Bandwidth of 200 kHz is not needed to accommodate an audio signal — 20 kHz to

30 kHz is all that is necessary for a narrowband FM signal. The 200 kHz bandwidth

allowed room for ±75 kHz signal deviation from the assigned frequency.

FM power is 1 kw to 5 kw but coverage area is 60 km to 70 km.

FM generates audio signal at pre stage.

3- SW (SHORT WAVE)

Shortwave radio is radio communication using the upper MF (medium frequency) and all

of the HF (high frequency) portion of the radio spectrum, between 1,800 –30,000 kHz. 

Shortwave radio received its name because the wavelengths in this band are shorter 

than 200 m (1500 kHz) which marked the original upper limit.

The amateur radio 1.8 MHz – 2.0 MHz band (known as the "top band") is the lowest-

frequency band considered to be 'shortwave'.

Medium used for short wave is ionize sphere.

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TRANSMISSION MEDIUM

 A transmission medium is a material substance that can propagate energy waves. It is

classified by,

  Linear medium if different waves at any particular point in the medium canbe superposed. 

  Bounded medium if it is finite in extent, otherwise unbounded medium.

  Uniform medium or homogeneous medium if its physical properties are unchanged at

different points.

  Isotropic medium if its physical properties are the same in different directions.

There is also some bands or layers present that covering the whole world. It is used as

a medium for the transmission of waves.

The components used to maintain a cooling of the plant of dish or a device that

recieve a signals from satellite is

LNA Low Noise Amplifer teperature is -200o.

LNB Low Noise Boster teperature is -60o.

Field strength metre is used to find the power (mw) of signal of RF (radio frequency)

signal.

TRANSMISSION 

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TRANSMITTER

 A transmitter is a deivce used to a transmit the signal of FM, AM, short wave etc to the

channel.

Transmitter have requires some stages,

1- FM power 10 watts to 50 watts for exciter.

2- Intermediate power.

3- Power amplifer (vaccume tube used). Output is 1.5 kw to 5 kw.

Source of signal

Amplified signal output 

In transmitter first HPF (High Pass Filter) is used then LPF

(Low Pass Filter).

RF AMPLIFIER 1 RF AMPLIFIER 2 Detector Stage

449 kHz

Oscillato

 

RF AMPLIFIER 1 RF AMPLIFIER 2 Detector Stage

TRANSMITTERS 

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SATELLITE COMMUNICATIONS

Introduction

In 1962, the American telecommunications giant AT&T launched the world's first true

communications satellite, called Telstar. Since then, countless communications satelliteshave been placed into earth orbit, and the technology being applied to them is forever 

growing in sophistication.

Basic Elements

Satellite communications are comprised of 2 main components:

The Satellite

The satellite itself is also known as the space segment, and is composed of three separate

units, namely the fuel system, the satellite and telemetry controls, and the transponder. Theprimary role of a satellite is to reflect electronic signals. In the case of a telecom satellite,

the primary task is to receive signals from a ground station and send them down to another 

ground station located a considerable distance away from the first.

The Ground Station

This is the earth segment. The ground station's job is two-fold. In the case of an uplink, or 

transmitting

Station, terrestrial data in the form of baseband signals, is passed through a baseband

processor, an up converter, a high powered amplifier, and through a parabolic dish antenna

up to an orbiting satellite. In the case of a downlink, or receiving station, works in the

reverse fashion as the uplink, ultimately converting signals received through the parabolic

antenna to base band signal.

Various Uses of Satellite Communications

Traditional Telecommunications

Cellular 

Satellite Messaging for Commercial Jets

SATELLITES 

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What are the requirements for a satellite to be geostationary?

1. Its revolutionary direction must be same as that of the earth, i.e. from west to east.

2. The time period of satellite’s revolution must be same to the time period of the rotation of 

earth along its polar axis, which is equal to 24 hours.

3. The equatorial plane of earth must be coplanar with the orbital plane of the satellites

revolution.

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SINPO

SINPO is an acronym for Signal, Interference, Noise, Propagation and Overall response.

The code is used for an overall assessment of the quality of the whole radio transmission,

especially in reception reports written by shortwave listeners. Each letter of the code stands

for a specific factor of the signal, and each item is graded on a 1 to 5 scale (where 1 stands

for very bad and 5 for very good).

It stands for:

S (Signal strength) 

 An assessment of how well the signal stands out above the background receiver noise.

I (Interference)

 An assessment of how well it stands out above competing signals.

N (Noise) 

 An assessment of how well it stands out above static or man-made noise.

P (Propagation)

 A measure of propagation-related distortion such as fading or flutter.

O (Overall merit)

 A measure of the extent to which all these factors contributed to the overall intelligibility of 

the entire contact.

SINPO 

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 As an example of SINPO report,