What is synchronous detection explain?

Synchronous detection preserves any phase information originally present in the modulating signal. With the exception of SECAM receivers, synchronous detection is a necessary component of any analog color television receiver, where it allows recovery of the phase information that conveys hue.

What is meant by synchronous demodulation?

For synchronous demodulation, a mixer is used. The incoming signal is fed into the signal input of the mixer, and a local oscillator signal on the same frequency as the carrier of the incoming signal is fed into the other.

What is synchronous amplitude modulation?

Synchronous detection is used for the detection or demodulation of Amplitude Modulation (AM). This form of modulation is still widely used for broadcasting on the long, medium and short wave bands despite the fact that there are more efficient forms of modulation that can be used today.

What signal must be present in an SSB demodulator?

SSB demodulation basics

In order to demodulate single sideband, SSB, it is necessary to reintroduce the carrier. To achieve this two main elements are required: Local oscillator: The local oscillator signal is needed to provide the locally produced carrier signal to re-introduce into the signal.

Communication Engineering - Demodulation of SSB-SC Signal (Coherent Detector)

What is SSB SC signal?

In radio communications, single-sideband modulation (SSB) or single-sideband suppressed-carrier modulation (SSB-SC) is a type of modulation used to transmit information, such as an audio signal, by radio waves. A refinement of amplitude modulation, it uses transmitter power and bandwidth more efficiently.

Which semiconductor device is used for detection of SSB waves?

A product detector is a type of demodulator used for AM and SSB signals, where the original carrier signal is removed by multiplying the received signal with a signal at the carrier frequency (or near to it).

What is synchronous or coherent detection why it is called coherent or synchronous?

Here, the same carrier signal (which is used for generating DSBSC signal) is used to detect the message signal. Hence, this process of detection is called as coherent or synchronous detection.

What are the methods for generating SSB SC signal?

There are three well known methods of SSB generation using analog techniques, namely the filter method, the phasing method, and Weaver's method.

What are the drawbacks of synchronous detector?

Explanation: Disadvantages of using synchronous detection of AM signal are that it needs an additional system for generation of carrier. The frequency of the locally generated carrier must be identical to that of transmitted carrier.

What is synchronous and asynchronous demodulation?

Synchronous demodulation is a method for extracting information from an AC carrier signal. Although asynchronous demodulation is used in Anser, synchronous demodulation illustrates basic concepts that are used in the asynchronous design.

What is coherent detection?

Coherent detection allows information to be encoded with two degrees of freedom, which increases the amount of information per channel. From: Optical Fiber Telecommunications VII, 2020.

What is asynchronous demodulator?

A receiver circuit includes an asynchronous demodulator having a demodulator input to receive a first signal and a demodulator output configured to provide a demodulated signal. The receiver circuit further includes a circuit, a multiplexer, and a synchronous demodulator.

What operates in synchronous detector?

A synchronous detector consists of a reference value mixed (multiplied) with a specific modulation frequency to generate a modulated stimulus signal that is fed to the system under test (SUT) (Fig. 1). The SUT output is again mixed with the same modulation frequency.

How would the sync detector help the sensor circuit?

Introduction. Synchronous detectors can extract small signals, buried in the noise floor, to measure properties such as very small resistance, light absorption or reflection against bright backgrounds, or strain in the presence of high noise levels. In many systems, the noise increases as the frequency approaches zero.

How does envelope detector work?

An envelope detector (sometimes called a peak detector) is an electronic circuit that takes a (relatively) high-frequency amplitude modulated signal as input and provides an output, which is the demodulated envelope of the original signal.

What are the different types of methods in SSB SC modulation?

We can generate SSBSC wave using the following two methods.

• Frequency discrimination method.
• Phase discrimination method.

Which method is practically used for SSB generation?

The two methods of SSB generation are (i) frequency discrimination method and (ii) the phase discrimination method. The frequency discrimination method of SSB generation given in figure 1, is based on suppressing one of the sidebands from the double-side-band suppressed carrier (DSB-SC) modulated waveform.

What is the signal bandwidth required in SSB SC?

Bandwidth of SSBSC Wave

We know that the DSBSC modulated wave contains two sidebands and its bandwidth is 2fm.

Is coherent and synchronous same?

If two synchronous signals have the same static phase they will be coherent.

Why is envelope detector not used in DSB-SC?

Generally an envelope detector can't be used to demodulate a DSB-SC. Demodulating a signal means to get back your original signal that was actually transmitted by any modulating techniques, or rather types. If the message is transmitted after modulating its amplitude, it's called amplitude modulation.

Is ask coherent or non-coherent?

ASK demodulation can be done in two ways. They are, Coherent detection (Synchronous demodulation) Noncoherent Detection (Asynchronous demodulation)

Can you use envelope detector for SSB SC demodulation?

Generally an envelope detector can't be used to demodulate a DSB-SC. Demodulating a signal means to get back your original signal that was actually transmitted by any modulating techniques, or rather types. If the message is transmitted after modulating its amplitude, it's called amplitude modulation.

Can you use envelope detector for SSB demodulation?

Hence, any of the coherent demodulation techniques applicable for DSB-SC signals can be used. It is evident that for a large carrier, the SSB+C can be demodulated by an envelope detector.

Why SSB signal is not used for broadcasting?

When carrier is shifted to bandpass, this one sided bandwidth becomes 9 MHz. This is nearly ten times as large as the total bandwidth occupied by all the channels of the AM radio. Use of SSB modulation would cut this in half but SSB is not used for video signals because of the complexity of the SSB receivers.