Simple and Mini FM Receiver

This is a very simple and mini fm radio receiver with good performances that works great even if the sensitivity is not too high. The working principle of this fm receiver may seem a little unusual. It is made of an oscillator (T2 and T3) that is synchronized with the received frequency of T1. This transistor works as a broadband preamplifier in VHF range.

Mini FM Receiver Circuit Diagram :

The oscillator is adjusted between 87 … 108 MHz with C5. Because of the synchronization, the oscillator output will have the same frequency deviation as the received signal from the fm antenna. This deviations are caused by the broadcasted audio informations. The frequency modulated signal show up on P1 + R5. Low pass filter R6/C6 extracts the audio signal and then is amplifier by T4 … T6 and transmitted at the output through C9 capacitor.

The coil details are presented in the fm receiver circuit diagram. The radio receiver is adjusted on different stations with the help of C5. P1 potentiometer is adjusted untill the best reception is obtained. If we attach an audio amplifier and a speaker then this fm receiver can be made very compact as a pocket radio.

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FM Receiver based on CXA1019

Its a high quality FM receiver circuit based on IC CXA1019 . CXA1019 is a monolithic silicon bipolar radio FM / AM receiver IC for Sony. Built in circuitry within the CXA1019 includes RF amplifier, mixer, oscillator, amplifier, quadrature detection circuit, tuning LED driver control electronic volume, FM detector, etc. HF section is only used in this circuit. The IC can be powered by a figure between 3 to 7 V DC and can lead to an 8 ohm speaker

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TDA1072A for AM receiver circuit

This TDA1072A integrated AM receiver circuit performs the active and part of the filtering functions of an AM radio receiver. TDA1072A is intended for use in mains-fed home receivers and car radios. The circuit design can be used for oscillator frequencies up to 50 MHz and can handle r. f. signals up to 500 mV. R.F. radiation and sensitivity to interference are minimized by an almost symmetrical design. The voltage-controlled oscillator provides signals with extremely low distortion and high spectral purity over the whole frequency range even when tuning with variable capacitance diodes. When required, band switching diodes can easily be applied. Selectivity is obtained using a block filter before the i.f. amplifier. The figure of the circuit is shown by the figure below;

The feature of TDA1072A is;
The inputs protected against damage by static discharge. Gain-controlled r.f. stage. Separately buffered, voltage-controlled and temperature-compensated oscillator, designed for simple coils. Internal generation of a.g.c. voltage with possibility of second-order filtering. Buffered field strength indicator driver with short-circuit protection.

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