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GENERAL DESCRIPTION: The TDA1572 integrated AM receiver circuit performs all the active functions and part of the filtering required of an AM radio receiver. It is intended for use in mains-fed home receivers and car radios. The circuit can be used for oscillator frequencies up to 50 MHz and can handle RF signals up to 500 mV. RF radiation and sensitivity to interference are minimized by an almost symmetrical design. The controlled-voltage oscillator provides signals with extremely low distortion and high spectral purity over the whole frequency range, even when tuning with variable capacitance diodes. If required, band switching diodes can easily be applied. Selectivity is obtained using a block filter before the IF amplifier. Features: Inputs protected against damage by static discharge Gain-controlled RF stage Double balanced mixer Separately buffered, voltage-controlled and temperature-compensated oscillator, designed for simple coils Gain-controlled IF stage with wide AGC range Fu...

Tuned Radio Frequency (TRF) Receiver Circuit diagram. Super heterodyne receivers have been mass-produced since around 1924, but for reasons of cost did not become successful until the 1930s. Before the second world war other, simpler receiver technologies such as the TRF receiver and the regenerative receiver were still widespread. Tuned Radio Frequency (TRF) Receiver Circuit diagram :   Tuned Radio Frequency (TRF) Receiver Circuit Diagram The circuit described here is based on the old technology, but brought up-to-date a The most important part of the circuit is the input stage, where positive feedback is used to achieve good sensitivity and selectivity. The first stage is adjusted so that it is not quite at the point of oscillation. This increases the gain and the selectivity, giving a narrow bandwidth. To achieve this, the potentiometer connected to the drain of the FET must be adjusted very carefully: optimal performance of the receiver depends on its setting. In ideal condit...

a AM portable ​​radio receiver using ZN414 IC. The ZN414 ic has now been replaced by the MK484 which is identical in performance and pinout. Designed around the popular ZN414 IC this receiver covers the range of medium wave band of approximately 550 to 1600 KHz with the values ​​indicated. The condenser coil and tuning can be taken from an old MW radio to save time. The ZN414 IC, has been replaced by the MK484. The integrated circuit is a 3 pin, tuned circuit radio frequency, and incorporates several RF stages, automatic gain control and an AM detector. It's easy to overload and voltage of th IC is critical to success. In this circuit a small voltage regulator turns on the transistor BC108B, 1N4148 diodes four, 2k7 and 10k resistor and the resistance of pre 820R. The 10k pot control acts as a receptor selectivity for all, control the operating voltage for the ZN414 (or MK484). The audio amplifier is built on an investment of 741 op-amp amplifier circuit. Additional current pulse i...

Block diagram of FM transmitter and receiver and its explanation FM transmitter Frequency Modulation is the process in which the frequency of the carrier signal is varied by the modulating signal while the amplitude remains constant Using Reactance modulator direct method The FM transmitter has three basic sections. The exciter section contains the carrier oscillator, reactance modulator and the buffer amplifier. The frequency multiplier section, which features several frequency multipliers. The power output section, which includes a low- level power amplifier, the final power amplifier, and the impedance matching network to properly load the power section with the antenna impedance. The essential function of each circuit in the FM transmitter may be described as follows. The Exciter The function of the carrier oscillator is to generate a stable sine wave signal at the rest frequency, when no modulation is applied. It must be able to linearly change frequency when fully modulated, w...