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RADIO RECEIVERS DESIGN

THIS RADIO RECEIVERS TUTORIALS SITE

This chapter covering receivers is pehaps one of the most interesting topics of all for newcomers. Receivers of all types tends to generate the most email enquiries.

We start out with the basics of radio receiver design then on to basic crystal radio sets, early radio receivers were mainly Tuned Radio Frequency TRF types both were designed for the reception of amplitude modulated AM signals. Later the superhetrodyne principle was established leading to rapid improvements in radio design and the use of higher frequencies.

One method of improving efficiency of the components used in a superhetrodyne receiver was the reflex receiver where both the audio and intermediate frequency stages were amplified simultaneously in a combined receiver stage. Further improvements in signal bandwidth efficiency led to the development of single sideband receivers SSB whilst still retaining the ability to receive continuous wave CW or as more widely known, morse code.

Later developments saw the advent of frequency modulation FM as a means of reducing noise interference as well as the transmitting of high quality audio.

BASICS OF RADIO RECEIVING SYSTEMS

Here we discuss the basics of radio transmission and reception to gain a broad overview of radio design.

CRYSTAL RADIO SET

Crystal Radio sets are the simplest system devised for the reception of amplitude modulated AM signals. Here is the basic crystal radio set. This basic old time radio uses no power other than that provided by the transmitting antenna from the radio station. Free power from the sky eh!. It truly is a marvel!. Some ham radio operators and other experimenters living in the vicinity of high powered AM Radio transmitters have used crystal radio sets to trickle charge batteries.

TUNED RADIO FREQUENCY or TRF SET

The TRF - tuned radio frequency - receiver was among the first designs available in the early days when means of amplification by valves became available. The basic principle was that all tuned radio frequency stages simultaneously tuned to the received frequency before detection and subsequent amplification of the audio signal.

SUPER-REGENERATIVE (REGEN) RECEIVER RADIO

A regenerative radio receiver is unsurpassed in comparable simplicity, weak signal reception, inherent noise-limiting and agc action and, freedom from overloading and spurious responses. The regenerative radio receiver or, even super-regenerative radio receiver or, "regen" if you prefer, is basically an oscillating detector receiver.

SUPERHETRODYNE RADIO RECEIVER

A superhetrodyne receiver works on the principle the receiver has a local oscillator called a variable frequency oscillator or V.F.O. which maintains a constant difference between itself and the received frequency resulting in a constant intermediate frequency.

AMPLITUDE MODULATION OR AM RADIO RECEIVER

A tutorial on the principles of AM radio receiver design. It is a complete three part electronic tutorial ranging from the very basics of radio design to the more sophisticated configurations used in short wave radio, ham radio or hobby electronics as a general purpose radio receiver.

FREQUENCY MODULATION OR FM RADIO RECEIVER

An a.m. receiver relies upon the original carrier signal (station frequency) having been amplitude modulated. This means the original amplitude (strength) varies at an audio rate. On the other an fm receiver has its transmitted signal varied at an audio rate while the amplitide component is over amplified and cut to remove an am component. This is a two part tutorial.

REFLEX RADIO RECEIVER

A reflex receiver is possibly only of value for curiosity or nostalgia purposes today but a very interesting concept really.

Principles of Transistor Circuits -
Introduction to design of amplifiers, receivers and digital circuits - S.W. Amos, M.R. James - 416 pages

From Book News, Inc.
New edition of a standard work useful as both an introduction for students and a handbook for practitioners, covering the basic elements of transistor circuit design. This ninth edition has been updated to cover the latest technology and applications, and many diagrams have been revised to bring them in line with current usage. Updated topics include thrystors, Darlington transistors, amplifiers, ring modulators, power supplies, optoelectronics and logic circuits. No bibliography. Book News, Inc.�, Portland, OR .

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