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 the function of 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.
What is the use of limiter and discriminator in FM receiver?
The limiter removes the noise in the received signal and gives a constant amplitude signal. This circuit is required when a phase discriminator is used to demodulate an FM signal. The output of the limiter is now applied to the FM discriminator, which recovers the modulating signal.
What is a radio discriminator?
The Discriminator output from a scanner is the raw, unfiltered signal that a scanner produces before it is sent to the audio stage for output through the speaker — also called the “baseband audio.” This discriminator source is required for applications such as Trunker, T4Win, UniTrunker, and DSD.
What is a frequency discriminator stage in a FM receiver?
In order to convert that signal back to regular audio the receiver needs something that can discriminate (or detect) the changes in frequency. Thus, the circuit that detects the FM signals is called a Frequency Discriminator (or sometimes Frequency Detector).
What discriminator means?
Definition of discriminator
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: one that discriminates especially : a circuit that can be adjusted to accept or reject signals of different characteristics (such as amplitude or frequency)
What is the frequency of discriminator?
Normalized sensitivity of the frequency discriminators (measured for 1 kHz modulation frequency) as a function of the carrier frequency detuning.
What is discriminator in analog communication?
The following figure shows the block diagram of FM demodulator using frequency discrimination method. This block diagram consists of the differentiator and the envelope detector. Differentiator is used to convert the FM wave into a combination of AM wave and FM wave.
What is a balanced discriminator?
Balanced Slope Detector (Balanced Frequency Discriminator) … As shown in the circuit diagram, the balanced slope detector consists of two slope detector circuits. The input transformer has a center tapped secondary. Hence, the input voltages to the two slope detectors are 180° out of phase.
What is selectivity of a receiver?
The selectivity of a radio receiver is the characteristic of the receiver which determines the extent to which the receiver is capable of distinguishing between a signal, that is a signal in a channel to which the radio receiver is tuned, and other signals, that is, signals in channels to which the receiver is not …
What is electronic discriminator?
[di′skrim·ə‚nād·ər] (electronics) A circuit in which magnitude and polarity of the output voltage depend on how an input signal differs from a standard or from another signal.
What is Armstrong method of FM generation?
From Wikipedia, the free encyclopedia. In 1933, Edwin H. Armstrong patented a method for generating frequency modulation of radio signals. The Armstrong method generates a double sideband suppressed carrier signal, phase shifts this signal, and then reinserts the carrier to produce a frequency modulated signal.
What do you mean by voltage discriminator how it works?
The discriminator (bias) makes it possible to prevent pulses below a certain height from being counted, thus reducing thermal and electronic noise from the counter.
What is the difference between ratio detector and foster Seeley discriminator circuit?
The ratio detector has the advantage over the Foster–Seeley discriminator that it does not respond to amplitude modulation (AM) signals, thus potentially saving a limiter stage, however, the output is only 50% of the output of a discriminator for the same input signal.
What are the disadvantages of Foster Seeley discriminator?
Disadvantages of Foster-Seeley FM discriminator:
Does not easily lend itself to being incorporated within an integrated circuit. High cost of transformer. Narrower bandwidth than the ratio detector.
How do you train a discriminator?
Steps to train a GAN
- Step 1: Define the problem. …
- Step 2: Define architecture of GAN. …
- Step 3: Train Discriminator on real data for n epochs. …
- Step 4: Generate fake inputs for generator and train discriminator on fake data. …
- Step 5: Train generator with the output of discriminator.
What is discriminator in mongoose?
Discriminators are a schema inheritance mechanism. They enable you to have multiple models with overlapping schemas on top of the same underlying MongoDB collection. … This function takes 3 parameters, a model name, a discriminator schema and an optional key (defaults to the model name).
What is meant by phase discriminator?
2. an electronic circuit that converts a frequency or phase modulation into an amplitude modulation for subsequent demodulation. 3. an electronic circuit that has an output voltage only when the amplitude of the input pulses exceeds a predetermined value.
How does FM demodulator work?
FM demodulation basics
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 balanced slope detector?
Balanced FM Slope Detector (Balanced Frequency Discriminator) … As shown in the circuit diagram, the balanced slope detector consists of two slope detector circuits. The input transformer has a center tapped secondary. Hence, the input voltages to the two slope detectors are 180° out of phase.
What is amplifier discriminator?
The AD8 amplifier-discriminator is a compact, low noise, high gain electronics module designed to be used in photomultiplier photon counting systems to generate TTL output pulses. … The slower output is intended to be used where it is required to eliminate photomultiplier afterpulses.
What is demodulation Tutorialspoint?
The process of extracting an original message signal from the modulated wave is known as detection or demodulation. The circuit, which demodulates the modulated wave is known as the demodulator. The following demodulators (detectors) are used for demodulating AM wave.
What is upper level discriminator?
Upper Level Discriminator.
A device for processing analogue electrical pulses generated from a photon detector. Pulses are transmitted only if they correspond to events of energy less than a certain threshold (the ULD setting or upper energy threshold).
What circuit is used for FM demodulation?
The FM demodulator is done with the help of a circuit called Phase Locked Loop (PLL). A PLL should have basic functional blocks like Voltage Controlled Oscillator (VCO), Phase comparator, Low Pass Filter (LPF) and Source follower.
What is Carson’s rule in FM?
Explanation: Carson’s rule states that the bandwidth required to transmit an angle modulated wave is twice the sum of the peak frequency deviation and highest modulating signal frequency.
Which instrument is necessary to align the FM detector in receiver circuit?
The Ratio detector or discriminator was widely used for FM demodulation before the introduction of integrated circuit demodulators and it is still found in some radios today. Ratio detector or discriminator was widely used for FM demodulation within radio sets using discrete components.
What is difference between specificity and selectivity?
The key difference between specificity and selectivity is that specificity is the ability to assess the exact component in a mixture, whereas selectivity is the ability to differentiate the components in a mixture from each other.
What is sensitivity of a receiver?
Receiver sensitivity is a measure of the minimum signal strength that a receiver can detect. … Receiver sensitivity is expressed in dBm. Since it represents how faint an input signal can be to be successfully received by the receiver, the lower the power level of the signal, the better.
How can you improve selectivity of a receiver?
Tweak the capacitors C2 and C7 to tune the receiver to the VHF band (65.8…73 MHz). Tweak the value of the resistor R1 to get maximum sensitivity of the receiver.
How does an FM ratio detector work?
The RATIO DETECTOR uses a double-tuned transformer to convert the instantaneous frequency variations of the fm input signal to instantaneous amplitude variations. These amplitude variations are then rectified to provide a dc output voltage which varies in amplitude and polarity with the input signal frequency.
What is direct and indirect method of FM generation?
The direct methods cannot be used for the broadcast applications. Thus, the alternative method i.e. indirect method called as the Armstrong method of FM generation is used. In this method the FM is obtained through phase modulation. A crystal oscillator can be used hence the frequency stability is very high.
What is the difference between direct and indirect methods of FM generation?
Direct FM. Indirect FM. In direct FM, as the information signal s received the instantaneous frequency is directly varied with the information signal. … In Indirect FM the signal is not received directly and the frequency does not vary with the signal.
What are the two methods of FM generation?
The following two methods generate WBFM wave.
- Direct method.
- Indirect method.
What is a pulse discriminator?
[′pəls di‚skrim·ə‚nād·ər] (electronics) A discriminator circuit that responds only to a pulse having a particular duration or amplitude.
What is limiter circuit?
In electronics, a limiter is a circuit that allows signals below a specified input power or level to pass unaffected while attenuating (lowering) the peaks of stronger signals that exceed this threshold. … Limiting is any process by which the amplitude of a signal is prevented from exceeding a predetermined value.
What is the advantages of ratio detector?
Advantages of the ratio FM detector
Simple to construct using discrete components. Offers good level of performance and reasonable linearity. Provides a good level of immunity to amplitude noise . Ratio detector has wider bandwidth than Foster Seeley discriminator.
What is discriminator loss?
Discriminator Loss
— Generative Adversarial Networks, 2014. Described mathematically, the discriminator seeks to maximize the average of the log probability for real images and the log of the inverted probabilities of fake images.
How does the discriminator improve its ability to detect fakes?
Essentially, the discriminator tells the generator how it should tweak each pixel so that the image can be more realistic. Let’s say the generator created an image and the discriminator thinks the image has a 0.29 (29%) probability of being a real image.
Why do we alternate between training the generator and training the discriminator?
Typically, we alternate between training the discriminator and the generator for one or more epochs. … As the generator improves with training, the discriminator performance gets worse because the discriminator fails to distinguish between real and fake.