Introduction to Channel Tuning
There is a unique adjustment for every channel. Resonance is acquired with coil's distributed capacitance, stray and trimmer capacitors. The oscillator coil is generally constructed with an aluminium or brass screw as the core for fine tuning. Inductance reduces with aluminium or brass core due to eddy currents in the metal. The screw is turned through a plastic gear wheel that is engaged while the fine tuning control is pushed-in against the holdings springs. So, the frequency variation acquired is sufficient to tune in the next channel station.
A number of receivers use automatic frequency running (AFT) in which an automatic frequency control is applied to the local oscillator in the tuner.
VARIOUS SECTIONS OF A VHF TUNER
As displayed in diagram the tuner contains the following sub-sections
WORKING OF THE TUNER
The Tuner must comprise input impedance equivalent to the characteristic impedance of the antenna feeder for highest signal transfer to the tuner and to prevent reflections on the line. The balun matches the double wire ribbon feeder impedance of 300 ohms to the 75 ohm impedance of RF amplifier. It contains bifilar windings' two 150 ohm (Z0) quarter-wave sections on a ferrite core. As displayed in diagram, at one end the two quarter-wave lines are connected in parallel to provide 75 ohm impedance and at another end they are linked in series to give an impedance equal to 300 ohms. If a coaxial cable is employed to connect the antenna to RF amplifier a similar parallel arrangement can be employed on both sides of the balun to give the match. Either side of the balun can be employed for input with the reverse side for output.
The RF amplifier is prepares to give sufficient gain to weak - signals. It is necessary to keep a high signal-to-noise ratio at the mixer that produces lot of noise. The equal noise voltage at the input of the RF amplifier sets a limit to the least signal strength which should be received to prevent excessive snow effects. As described before RF amplifier besides giving gain to the selected channel signals
a. Stops radiation from the local oscillator and
b. Rejects image frequency signals.
The local oscillator produces an un modulated sinusoidal (Carrier Wave) voltage which is heterodyned in the mixer along with the incoming RF signal to influence frequency it translation to the IF band The local oscillator frequency is changed when a dissimilar channel is chosen to keep difference equal to the intermediate frequency among the tuned channel carrier frequency and the local oscillator frequency. The fine tuning control permits the oscillator frequency to be changed over a narrow range.
The task of this circuit is to convert the incoming RF signal frequencies from dissimilar channels into a common IF pass-band of the receiver. This is acquired in the mixer through heterodyning or beating the local oscillator frequency with the signal acquired from the RF amplifier. The mixer stage that combined with the local oscillator may be referred like a frequency converter.
Latest technology based Electrical Engineering Online Tutoring Assistance
Tutors, at the www.tutorsglobe.com, take pledge to provide full satisfaction and assurance in Channel Tuning homework help via online tutoring. Students are getting 100% satisfaction by online tutors across the globe. Here you can get homework help for Channel Tuning, project ideas and tutorials. We provide email based Channel Tuning homework help. You can join us to ask queries 24x7 with live, experienced and qualified online tutors specialized in Channel Tuning. Through Online Tutoring, you would be able to complete your homework or assignments at your home. Tutors at the TutorsGlobe are committed to provide the best quality online tutoring assistance for Electrical Engineering homework help and assignment help services. They use their experience, as they have solved thousands of the Electrical Engineering assignments, which may help you to solve your complex issues of Channel Tuning. TutorsGlobe assure for the best quality compliance to your homework. Compromise with quality is not in our dictionary. If we feel that we are not able to provide the homework help as per the deadline or given instruction by the student, we refund the money of the student without any delay.
www.tutorsglobe.com offers Programming Languages homework help, assignment help, case study, writing homework help, online tutoring assistance by computer science tutors.
Tropical and Temperate Flora and Fauna tutorial all along with the key concepts of Tropical and Temperate Regions, Tropical and Temperate Flora, Tropical and Temperate Fauna, Dispersal of Plants, Means of Dispersal of Animals and Principles of Animal Distribution
Introduction to Marginal Costing and Break Even Analysis - Marginal Costing is not a technique of costing such as job, batch or contract costing. It is actually a method of costing where only variable manufacturing costs are taking into account when determining the cost of goods that are sold and also for valuation of inventories.
tutorsglobe.com protein translation assignment help-homework help by online protein metabolism tutors
Magnetism as a Relativistic Phenomenon tutorial all along with the key concepts of Electric Charges As Seen By Different Observers In Different Frames of Reference, Electric and Magnetic Forces
tutorsglobe.com management of hazardous wastes assignment help-homework help by online waste management tutors
Avail quality driven Brand Management Assignment Help from qualified tutors at low prices and stand out among your classmates.
Infrared spectroscopy tutorial all along with the key concepts of Basic principles of infrared spectrometry, Types of molecular vibrations, Group frequencies, Instrumentation, Application
tutorsglobe.com negative interactions assignment help-homework help by online relationships among organisms tutors
Theory and lecture notes of Building Models all along with the key concepts of building models, essence of model-building, homework help, assignment help, understanding macroeconomics. Tutorsglobe offers homework help, assignment help and tutor’s assistance on Building Models.
Preparation of Esters-Aldehydes-Ketones tutorial all along with the key concepts of Preparation of esters, Concept of aldehydes and ketones, Physical properties, Chemical properties
Theory and lecture notes of Adaptive Expectations all along with the key concepts of adaptive expectations, Long Run under Adaptive Expectations, Static Expectations. Tutorsglobe offers homework help, assignment help and tutor’s assistance on Adaptive Expectations.
Presentation of VLF Results tutorial all along with the key concepts of Filtering, Displaying VLF data, VLF/EM comparisons, Natural and controlled-source audio-magnetotellurics, CSAMT practicalities
tutorsglobe.com memory assignment help-homework help by online co-ordination systems tutors
tutorsglobe offers you accounting assistance in classroom assignments, homework help, textbooks solutions, accounting course help, online tutoring, and problems solutions, accounting tutors are available for help 24x7.
1948803
Questions Asked
3689
Tutors
1468938
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!