What is the function of a discriminator in FM receiver?
discriminator-a circuit or device in which amplitude variations are de- rived from frequency or phase varia- tions. The circuit has many uses, but is popular as a detector in FM receivers. ahead of a discriminator or ratio detector to clip AM energy and generally clean up a noisy FM signal.
What is discriminator in FM receiver?
discriminator: The part of an FM receiver that extracts the desired signal from an incoming FM wave by changing frequency variations into amplitude variations. (
Which signal is provided by the discriminator used in FM stereo system?
The FOSTER-SEELEY DISCRIMINATOR is also known as the PHASE-SHIFT DISCRIMINATOR. It uses a double-tuned rf transformer to convert frequency variations in the received fm signal to amplitude variations. These amplitude variations are then rectified and filtered to provide a dc output voltage.
What is frequency discriminator?
A frequency discriminator is defined as a converter of frequency changes into amplitude changes. Discriminators are used in various applications, one of which is the direct demodulation of fre- quency modulated signals [1, 2]. Mixing a broad- band signal down to an intermediate frequency, can be a tedious job.
How does an FM discriminator work?
In any radio that is designed to receive frequency modulated signals there is some form of FM demodulator or detector. This circuit takes in frequency modulated RF signals and takes the modulation from the signal to output only the modulation that had been applied at the transmitter.
What is difference between AM and FM receiver?
In AM, a radio wave is known as the “carrier” or “carrier wave” is modulated in amplitude by the signal that is to be transmitted. In FM, a radio wave is known as the “carrier” or “carrier wave” is modulated in frequency by the signal that is to be transmitted.
How do FM receivers work?
A radio or FM receiver is an electronic device that receives radio waves and converts the information carried by them to a usable form. An antenna is used to catch the desired frequency waves. Of the radio waves, FM is the most popular one. Frequency modulation is widely used for FM radio broadcasting.
What is the basic principle of demodulating FM signal?
FM demodulation is a key process in the reception of a frequency modulated signal. Once the signal has been received, filtered and amplified, it is necessary to recover the original modulation from the carrier. It is this process that is called demodulation or detection.
What is if of superheterodyne FM receiver?
A superheterodyne receiver, often shortened to superhet, is a type of radio receiver that uses frequency mixing to convert a received signal to a fixed intermediate frequency (IF) which can be more conveniently processed than the original carrier frequency.
What are the advantages of AM over FM?
The advantages of AM radio are that it is relatively easy to detect with simple equipment, even if the signal is not very strong. The other advantage is that it has a narrower bandwidth than FM, and wider coverage compared with FM radio.
How to realign a limiter discriminator FM receiver?
The AM generator method for realigning limiter-discriminator receivers, described above, is summarized in Table 13-1. 13-3. Ratio-Detector Realignment The limiter stage is ordinarily omitted when the ratio detector is used, since the ratio detector does its own limiting.
Which is better A Fm ratio detector or discriminator?
Both types were widely used, but the FM ratio detector was the more common because it offered a better level of amplitude modulation rejection of amplitude modulation. This enabled the circuit to provide a greater level of noise immunity as most noise is amplitude noise.
What are the requirements for FM receiver realignment?
This last adjustment is the most critical of all those involved in FM- receiver realignment. To ensure its accuracy, the following two conditions must be satisfied: 1. The i-f signal must be exactly at the intermediate frequency specified for the receiver (10.7 mc is the common standard value).
Why are FM detector circuits not effective for realignment?
The Effect of FM Detector Circuits on FM-Receiver Realignment The reason certain AM realignment procedures are not effective for FM realignment is the fact thatlimiting,or the similar effect in a ratio detector, is part of the FM receiving process. 444 SEC. 13-2]REALIGNING FM RECEIVERS •445