The difference between frequency modulation and phase modulation is that with frequency modulation the angular frequency of the signal is modified while with the phase modulation, the phase angle of the signal is modified.

Frequency Modulation and Phase Modulation

Phase modulation and frequency modulation are related because changes in the phase of a signal result in corresponding changes in its frequency. When the phase of a signal is modulated, it causes variations in the frequency of the signal as well. Therefore, in practice, it is difficult to separate phase modulation from frequency modulation, especially in communication systems where both aspects are interconnected.

what is phase modulation

changing of the phase depending upon the modulated signal is said to be a phase modulation

Frequency modulation Phase modulation

i dont know ans. of this.

QAM is a combination of phase modulation & amplitude modulation.

For phase opposition disposition (POD) modulation all carrier waveforms above zero reference are in phase and are 180 out of phase with those below zero.

angle modulation is called non linear modulation because the information is stored in phase of the carrier signal

Frequency modulation and Phase modulation

A phase modulation

I think it is Frequency Modulation with Phase modulation which it the most bandwidth efficient

The reason it is called exponential (non-linear) modulation is that the information is encoded within the phase of carrier.

Advantage - 1. Phase modulation & demodulation is easy compared to Frequency modulation. 2. Phase modulator is used in determining velocity of moving target by extracting Doppler information. Doppler information needs stable carrier which is possible in phase modulation but not in frequency modulation. Disadvantage - 1. Phase ambiguity comes if we exceed its modulation index pi radian(180 degree). 2. we need frequency multiplier to increase phase modulation index.

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A phase-locked loop (PLL) can be used as a universal detector for Amplitude Modulation (AM) by utilizing its ability to track the phase and frequency of the incoming modulated signal. The PLL locks onto the carrier frequency of the AM signal, allowing it to demodulate the envelope variations caused by the modulation. By comparing the output of the PLL with the original carrier frequency, the modulation information can be extracted as the difference between the two signals. This makes the PLL an effective detector for demodulating AM signals across a wide range of frequencies and modulation depths.

Phase Shift Modulation

Advantages: it improves frequency stability.

phase modulation n demodulation is easy as compared to frequency modulation.

amplitude modulation is used

Some examples of applications of phase modulators are: * A phase modulator within a laser resonator of a single-frequency laser can be used for wavelength tuning, or for active mode locking (FM mode locking) of a laser. * A phase modulation of a beam with moderate modulation strength is often used in laser frequency stabilization schemes, e.g. with the Pound-Drever-Hall method. * Various kinds of interferometers and setups for spectroscopic measurements require phase modulators, often with a periodic drive signal. * Some metrology applications require frequency combs, generated by sending a single-frequency beam into a phase modulator. In that case, the phase modulation often needs to be strong in order to obtain a large number of optical sidebands. * In data transmitters of optical fiber communication systems, phase modulators can be used for encoding the transmitted information. An example is the method of phase shift keying. Source: http://www.rp-photonics.com/phase_modulators.html

Amplitude

Frequency

An analog or digital modulator can perform amplitude, frequency, and phase modulation. These modulators are commonly used in communication systems to modulate a carrier signal in order to transmit information.

It is a way to see differentences between items. Like: Cow is to barn as elephant is to zoo.

circuit of modulation PSK

Carrier signals that carry information by the process of frequency- or phase-modulation.

In a Michelson interferometer, phase modulation causes the interference fringes to shift along the detector. This shift changes the relative path length of the interfering beams, causing variations in the interference pattern amplitude. By analyzing these variations in intensity, the phase modulation can be detected as changes in the interferometer's output signal.

Tien Manh Nguyen has written:

'Phase-ambiguity resolution for QPSK modulation systems' -- subject(s): Ambiguity, Frequency synchronization, Modulation (Electronics), Phase shift keying, Signal reception, Space communication

This refers to the concept of modulation, where a carrier wave's strength or characteristics are modified to convey information. Modulation techniques include amplitude modulation (AM), frequency modulation (FM), and phase modulation (PM). These techniques are commonly used in telecommunications for transmitting signals over long distances.

Raju Pandey has written:

'Noncoherent detection of continuous phase modulation'

Since we can generate fm from phase modulation, thus both are related to each other

it causes over modulation .... that is the phase reversal of carrier signal ..... the modulated wave then exhibits envelope distortion which results in loss of data .....

The advantage of a binary phase-shift keying is that within a given bandwidth, modulation of higher orders allow to carry higher rates.

by maximizing the measurable differences between shifts in phase and amplitude

to maintain the constant frequency and the phase parameters at the output

The advantage of a binary phase-shift keying is that within a given bandwidth, modulation of higher orders allow to carry higher rates.

Charles Richard Abbey has written:

'Detection of phase-modulated signals using digital techniques' -- subject(s): Phase modulation

Rudolf Donocik has written:

'Theory of phase-controlled oscillations' -- subject(s): Linear operators, Nonlinear theories, Oscillations, Phase modulation

In signal processing, modulation means altering the wave form in some manner. This could include altering one of the three factors of a wave form. These are the amplitude, frequency, and phase.

I W. Turner has written:

'Digital modulation/demodulation using phase reversal keying'

Differential Phase shift key (DPSK)

Quadrature amplitude modulation (QAM)

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Three different modulating techniques are emploed to provide digital television (i.e. satellite, cable, UHF ) and these are known as DQPSK, QAM and COFDM. Each technique is a variation of phase modulation. QAM also takes advantage of amplitude as well as phase changes.

IF we use frequency modulation for transmitting video signal this can cause phase shifting .and eyes can percieve this distortion effect easly . and requires more bandwidth to send the signal .Color levels are adjusted by amplitude in TV .So it s more logic to use Amplitude modulation .

In older Microwave link systems they used basic FM or Phase Modulation, modern MW radio links use complex modulation protocols, i.e. 64 QAM, 256 QAM among several other modern modulation types which nowadays enable very large bandwidths and also enables a much more error free end to end signal. These new modulation techniques are also used by your computers Wi-Fi which also operate in the Microwave bands.

When modulated with a radio frequency signal, they will indeed carry information. As in fibre-optic cables. The modulation may be of the several commonly used types, amplitude, frequency, phase ... modulation.