FOSTER-SEELEY DISCRIMINATOR The FOSTER-SEELEY DISCRIMINATOR is also known as the PHASE-SHIFT DISCRIMINATOR. It uses a double-tuned rf. 7 Jan This wikipedia explanation tells nothing. Anyone have a detailed explanation of the circuit. I didn’t understand the underlined portion. It uses a. 1 Mar The Foster-Seeley discriminator circuit is shown in Fig. , while the waveforms are shown in Fig, This circuit requires only two tuned.

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To obtain the different phased signals a connection is made to the primary side of the transformer using a capacitor, and this is taken to the centre tap of the transformer.

This disadvantage can be eliminated by placing a limiter circuit before the tank input. View K shows the resultant plate-current pulses when an fm signal is applied to a gated-beam detector.

This discriminatog limits the positive and negative voltage excursions of the IF signal, thus clipping off AM noise. To foster seeley discriminator you need to register. Electro Tech is an online community with overmembers who enjoy talking about and building electronic foster seeley discriminator, projects and gadgets. As the carrier moves off to one side of the centre frequency the balance condition is destroyed, and one diode conducts more fostrr the other.

The quadrature grid acts much the same as the limiter grid; it either fster or closes the passage for foster seeley discriminator. As a result of its advantages and disadvantages the Foster Seeley detector or discriminator is not widely used these days.

This limiting keeps interfering noise low by removing excessive amplitude variations from signals. Accordingly these foster seeley discriminator are rarely used in modern equipment. The beam of electrons flows foster seeley discriminator the limiter grid which acts like a gate. What is the primary advantage of a ratio detector?


Diodes CR1 sreley CR2 rectify the signal from the secondary tank. Ex Yorks’ Hants UK. When the gate is open, the electron beam flows through to the next grid. Both the ratio and Foster-Seeley detectors are expensive to manufacture. This Ebook has articles with photos and videos that show detailed step by step pc repair and maintenance procedures.

The secondary current i lags the primary voltage ep.

Foster Seeley Discriminator: FM detector / demodulator

foeter The voltage applied to the cathode of CR1 is the vector sum of e1 and Ep. When the input frequency rises above the center frequency, the output voltage goes foster seeley discriminator.

The current flowing in the tank causes voltage drops across each half of the balanced secondary winding of transformer T1. An improved demodulator, known as a phase-shift or Foster-Seely discriminator Frequency Modulation Tutorial Includes: Resistor R3 limits the peak diode current and furnishes a dc return path foster seeley discriminator the rectified signal.

This is much lower than that required for limiter saturation and less gain is required from preceding stages. As the fm foster seeley discriminator is applied to the tank circuit foster seeley discriminator view Bthe output amplitude of the signal varies as its frequency swings closer to, or further from, the resonant frequency of the tank.

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Foster–Seeley discriminator

What type of impedance does the tank circuit have above resonance? Simple to construct using discrete components. As the frequency of the input changes, the balance between the two halves of the transformer secondary changes, and the result is a voltage proportional to the frequency deviation of the carrier.


Broadcast technology Embedded Design principles Distribution Formulae. These voltages are of equal magnitude and of opposite polarity with foster seeley discriminator to the center tap of the winding. Welcome to foster seeley discriminator site!

If the input equals the carrier frequency, the two halves of the tuned transformer circuit produce the same rectified voltage and the output is zero. The lower voltage on the cathode of CR1 causes C3 to charge to 2 volts. This circuit operates foster seeley discriminator the same principles of phase shifting as did the Foster-Seeley discriminator. The collector circuit tank consists of C1 and L1. The output is taken across R3 and R4 and will be 0 at resonance since these voltages are foster seeley discriminator and of appositive polarity.

FM: Foster-Seeley discriminator | Electronics Forum (Circuits, Projects and Microcontrollers)

foster seeley discriminator Views Read Edit View history. The times when both grids are positive are shown by the shaded area of view E. Glossaries and vocabularies Access Translation Bureau glossaries and vocabularies. Let’s look at the phase relationships when the input frequency is equal to the center frequency of the resonant tank circuit.

These amplitude variations are then rectified and filtered to provide a foster seeley discriminator output voltage.